SEARCH · PubMed Health

Results for “Skeleton”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources

PubMed1984

Influence of the antimicrotubular agents, colchicine and vinblastin, on the uptake of americium by rat liver, kidneys, and skeleton.

The influence of pretreatment with colchicine and vinblastin sulfate, administered ip at dosages of 2.5 mumol/kg on the uptake of im or iv injected 241Am by rat liver, kidneys, and skeleton was investigated. Both agents reduced the nuclide uptake by liver and increased the 241Am contents in kidneys and skeleton. The effect was dependent on the time interval between pretreatment and nuclide injection as well as on the dose of the agents. The minimum effective dose was approximately 0.5 mumol/kg. A thousand times higher po dose of carbon tetrachloride was less effective than the highest colchicine dose. Lumicolchicine (2.5 mumol/kg) did not increase the 241Am skeleton and kidney contents and was less effective in reducing the hepatic content than colchicine or vinblastin. At the light microscopy level, livers of the rats appeared normal after the standard colchicine dose (1 mg/kg), but concentrations of four enzymes, which may indicate damage to the liver, were significantly raised.

Alanine Transaminase↗

PubMed1992

A model of spectrin as a concertina in the erythrocyte membrane skeleton.

To maintain its distinctive biconcave shape, the erythrocyte has a skeleton composed largely of the protein spectrin, which associates closely and exclusively with the cell membrane. Although the membrane skeleton forms through specific protein-protein interactions of defined stoichiometry, it has a flexible structure and organization due to the unusual molecular properties of spectrin. Here we describe these properties and propose a model to account for the extensibility of spectrin and for its organization in the skeleton.

Journal Article↗

PubMed1993

The membrane skeleton.

One important element that defines cell shape is the membrane skeleton. This filamentous network is closely apposed to the cytoplasmic face of the plasma membrane where it gives mechanical support to the membrane, provides specific attachment sites for cytoskeletal components and helps to organize some integral membrane proteins into domains. The membrane skeleton of erythrocytes has been studied extensively by biochemical and ultrastructural methods, but similar structures in other cell types are just beginning to be defined. In this review, David Pumplin and Robert Bloch draw attention to these nonerythroid skeletons and compare and contrast them with the erythrocyte model.

Journal Article↗

PubMed2006

Removal of C-ring from the CD-ring skeleton of 1alpha,25-dihydroxyvitamin D3 does not alter its target tissue metabolism significantly.

It is now well established that 1alpha,25(OH)2D3 is metabolized in its target tissues through the modifications of both side chain and A-ring. The C-24 oxidation pathway is the side chain modification pathway through which 1alpha,25(OH)2D3 is metabolized into calcitroic acid. The C-3 epimerization pathway is the A-ring modification pathway through which 1alpha,25(OH)2D3 is metabolized into 1alpha,25(OH)2-3-epi-D3. During the past two decades, a great number of vitamin D analogs were synthesized by altering the structure of both side chain and A-ring of 1alpha,25(OH)2D3 with the aim to generate novel vitamin D compounds that inhibit proliferation and induce differentiation of various types of normal and cancer cells without causing significant hypercalcemia. Previously, we used some of these analogs as molecular probes to examine how changes in 1alpha,25(OH)2D3 structure would affect its target tissue metabolism. Recently, several nonsteroidal analogs of 1alpha,25(OH)2D3 with unique biological activity profiles were synthesized. Two of the analogs, SL 117 and WU 515 lack the C-ring of the CD-ring skeleton of 1alpha,25(OH)2D3. SL 117 contains the same side chain as that of 1alpha,25(OH)2D3, while WU 515 contains an altered side chain with a 23-yne modification combined with hexafluorination at C-26 and C-27. Presently, it is unknown how the removal of C-ring from the CD-ring skeleton of 1alpha,25(OH)2D3 would affect its target tissue metabolism. In the present study, we compared the metabolic fate of SL 117 and WU 515 with that of 1alpha,25(OH)2D3 in both the isolated perfused rat kidney, which expresses only the C-24 oxidation pathway and rat osteosarcoma cells (UMR 106), which express both the C-24 oxidation and C-3 epimerization pathways. The results of our present study indicate that SL 117 is metabolized like 1alpha,25(OH)2D3, into polar metabolites via the C-24 oxidation pathway in both rat kidney and UMR 106 cells. As expected, WU 515 with altered side chain structure is not metabolized via the C-24 oxidation pathway. Unlike in rat kidney, both SL 117 and WU 515 are also metabolized into less polar metabolites in UMR 106 cells. These metabolites displayed GC and MS characteristics consistent with A-ring epimerization and were putatively assigned as C-3 epimers of SL 117 and WU 515. In summary, we report that removal of the C-ring from the CD-ring skeleton of 1alpha,25(OH)2D3 does not alter its target tissue metabolism significantly.

Animals↗

PubMed2004

Skeletonized radial artery graft with the St. Jude Medical Symmetry Bypass System (aortic connector system).

BACKGROUND: We report our initial experience with an automatic anastomotic device using skeletonized radial artery in patients requiring off-pump coronary artery bypass grafting (CABG). METHODS: St. Jude Medical, Inc, Symmetry Bypass System (aortic connector system [ACS]) (St Jude Medical, St. Paul, MN) was used in ten patients. Ten consecutive patients who underwent off-pump CABG and who received at least one radial artery graft proximal anastomosis using the ACS were evaluated. The radial artery (RA) was harvested in a skeletonized fashion and applied to the ACS in the same manner as applying saphenous vein graft. The creation of the anastomosis lasted no longer than a few seconds. RESULTS: Our attempt to use the ACS for proximal anastomosis of the RA was successful in all ten patients. Mean operating time was 3.2 +/- 0.6 minutes and an average of 3.0 +/- 0.9 bypass grafts (range, 2 to 5 grafts) were performed. There was no postoperative fatal complication. Postoperative angiographic control showed that all grafts were widely patent including grafts other than the RA. During the mean postoperative follow-up of 10.3 +/- 2.9 months, there was no cardiac-related event in any patient. CONCLUSIONS: The St. Jude Medical Symmetry aortic connector system allows the construction of uniform and widely patent anastomoses in RA graft and does not require aortic side biting. Skeletonization of the RA is a safe and effective technique for applying ACS in off-pump CABG using multiple arterial grafts.

Aged↗

PubMed2005

Skeletonized gastroepiploic artery as a composite graft for total arterial revascularization.

BACKGROUND: Despite the purported advantages of using a gastroepiploic artery graft during coronary artery bypass, insufficient potential flow capacity and vasospasm remain major concerns. We assessed the efficacy and results of using a skeletonized composite gastroepiploic artery graft in situations in which bilateral internal thoracic and radial arteries could not be used. METHODS: Between January 2000 and August 2002, 37 patients (25 men, 12 women; mean age, 59.9 years) underwent grafting with composite grafts using a skeletonized left internal thoracic artery plus the gastroepiploic artery. Coronary angiograms were performed in the immediate (median, 14 days, 36 patients) and early (median, 348 days, 32 patients) postoperative periods. Off-pump coronary artery bypass grafting was performed in all but 2 patients. RESULTS: There were no deaths. The respective postoperative patencies of the left internal thoracic artery and gastroepiploic artery were 36 of 37 (97.2%) and 73 of 75 (97.3%) at the immediate period, and 34 of 34 and 62 of 67 (92.5%) at the early period. During follow-up, only 1 patient required percutaneous intracoronary intervention for gastroepiploic artery occlusion. CONCLUSIONS: Skeletonized composite gastroepiploic artery grafts showed satisfactory clinical and angiographic results in situations in which bilateral internal thoracic and radial arteries could not be used. Although it needs longer follow-up, these early results demonstrated that the gastroepiploic artery may be a useful option in some situations of total arterial revascularization, used either as an in situ or as a composite graft.

Adult↗

PubMed2004

Genetic variations that regulate bone morphology in the male mouse skeleton do not define its susceptibility to mechanical unloading.

Genetics can substantially influence bone morphology and may define the skeleton's response to mechanical unloading. Recent data indicated that disuse produces different site-specific responses in the skeleton of genetically distinct adult female C3H/HeJ (C3H) and BALB/cByJ (BALB) mice; while disuse BALB mice had significantly less bone than age-matched controls in the distal and diaphyseal femur, the removal of weight bearing had a much smaller influence in C3H. Using adult male mice from these two inbred strains, the hypothesis was tested that interactions between genetic variations and anatomic location define bone morphology and its susceptibility to unloading. Four-month-old male BALB and C3H mice were either subjected to 21 days of hindlimb unloading or served as controls. Multiple cortical and trabecular regions within the distal and diaphyseal femur were analyzed by micro-computed tomography. C3H controls had significantly greater diaphyseal and metaphyseal cortical bone area (45% and 32%) and greater metaphyseal trabecular bone volume fraction (67%) than BALB controls, but epiphyseal trabecular bone volume fraction was similar between the two strains. Despite these substantial, site-specific differences in bone morphology, disuse induced similar changes in bone morphology in these two strains. Compared to controls, disuse BALB and C3H had significantly less metaphyseal (17% and 19%) and epiphyseal (10% and 13%) trabecular bone, while diaphyseal and metaphyseal cortical bone geometry was unaffected. These data indicate that the genetic variations that caused spatially nonuniform differences in trabecular and cortical bone morphology between the two strains had little influence on the susceptibility of a specific site to unloading. Cross-gender comparisons with previous data from female BALB and C3H mice further suggest strong interactions by which gender, genotype, and anatomical location define the response of the skeleton to the removal of weight bearing.

Animals↗

PubMed2005

Bone geometry and density in the skeleton of pre-pubertal gymnasts and school children.

We have studied the differences between the peripheral and axial skeleton of pre-pubertal gymnasts and controls. We hypothesised that compared to controls, gymnasts would have larger and stronger radius and tibia diaphyses with greater bone mineral content and larger cross-sectional muscle area. At the distal metaphyseal sites of the radius and tibia, gymnasts would have greater bone cross-sectional area and total and trabecular volumetric bone mineral density (vBMD). Differences between the lumbar spine, total body and body composition in gymnasts versus controls were also studied. Peripheral quantitative computed tomography (pQCT) was used to measure bone geometry, density and muscle of the peripheral skeleton; dual energy X-ray absorptiometry (DXA) for total body and axial measurements. Eighty-six pre-pubertal children, 44 gymnasts (mean age 9.0 years, range 5.4-11.9 years) and 42 controls (mean age 8.8 years, range 5.6-11.9 years) were studied. Eighty-four children were Caucasian, one child was mixed race, one Chinese. Data were adjusted for age, sex and height. Differences in the effect size between sexes were also tested. At the 50% radius diaphysis gymnasts had larger bones (9.2%, p = 0.0054) with greater cortical area (8.2%, p = 0.022) and stress strain index (surrogate measure of bone strength) than controls (13.6%, p = 0.015). The effect size was different between males and females for cortical thickness (p = 0.03). At the 65% tibia diaphysis, gymnasts had greater cortical area (5.3%, p = 0.057) and thickness (6.2%, p = 0.068) than controls; consequently, bone strength was 5.4% higher (p = 0.14). There were no significant differences in cortical volumetric bone mineral density (vBMD) at the radius or tibia diaphysis between the groups. There was a difference in effect size for tibia muscle cross-sectional area between the sexes (p = 0.035). At the distal radius and tibia total and trabecular vBMD was greater (Total: radius 17%, p < 0.0001, tibia: 5.7%, p = 0.0053; trabecular: radius 21%, p < 0.0001, tibia 4.5%, p = 0.11). Bone size was not different in gymnasts compared to controls Lumbar spine BMC (12.3%, p = 0.0007), areal bone mineral density (aBMD) (9.1%, p = 0.0006) and bone mineral apparent density (BMAD) (7.6%, p = 0.0047) were greater in gymnasts but vertebral size was not significantly different. Likewise, total body BMD (3.5%, p = 0.0057) and BMC (4.78%, p = 0.085) were greater in gymnasts but there were no differences in skeletal size. These data suggest site-specific differences in how the pre-pubertal skeleton develops in response to the repetitive loading it experiences when participating in regular gymnastics. At diaphyseal sites these differences are predominantly in the bone and muscle geometry and not density. Conversely, at trabecular sites, the differences are increased density rather than geometry. In conclusion, the present study has demonstrated skeletal differences between gymnasts and controls. These differences appear to be site and sex specific.

Absorptiometry, Photon↗

PubMed2004

Skeletonized bilateral internal mammary arteries for total arterial myocardial revascularization.

BACKGROUND: Bilateral internal mammary artery (IMA) grafting is associated with an improved long-term survival, low rates of recurrence of angina and late myocardial infarction. However, because of the inadequate length of the conduit, use of bilateral internal thoracic artery grafting occasionally is not suitable for complete revascularization. To overcome this limitation, extra length can be obtained by skeletonization of both IMAs. We decided to prospectively assess the safety of this technique. METHODS: One hundred patients with a mean age of 52.5 +/- 13.1 years underwent complete revascularization with skeletonized bilateral internal mammary arteries on cardiopulmonary bypass (CPB). The right internal mammary artery (RIMA) was used as a free graft connected to the in situ left IMA (LIMA) in 88 patients. A free LIMA was attached to in situ RIMA in 12 patients. The average number of grafts was 3.2 per patient (range: 2-4 grafts per patient). Mean left ventricular ejection fraction was 60% (range: 25-80%). RESULTS: No patient required reexploration for bleeding, and no patient died within 30 days after operation. On the basis of electrocardiographic changes, three patients sustained a perioperative myocardial infarction. One patient had a sternal wound infection. Mean follow-up was 24 months (range: 6-36 months). The actuarial survival rate was 99 +/- 1% at 3 years. No myocardial infarctions were reported during the follow-up. Three patients had recurrent angina with conduit occlusion diagnosed on coronary angiography. CONCLUSION: Complete myocardial revascularization with skeletonized bilateral internal mammary arteries is a safe and reliable technique with excellent early and mid-term results.

Journal Article↗

PubMed2004

Total arterial revascularization with composite skeletonized gastroepiploic artery graft in off-pump coronary artery bypass grafting.

BACKGROUND: Total arterial revascularization in coronary artery bypass grafting has recently become of great interest to many surgeons. At the same time, off-pump coronary bypass grafting has also become a popular procedure because of its low morbidity and mortality. Here we report our recent series of off-pump coronary bypass grafting performed with a grafting technique we developed by using the skeletonized gastroepiploic artery and the radial artery composite graft to achieve total arterial revascularization. METHODS: From September 2000 to April 2003, 98 patients underwent total arterial revascularization with the skeletonized gastroepiploic artery and radial artery composite graft on the beating heart. We used the gastroepiploic artery graft of choice in patients with a right coronary artery lesion. When multiple grafting was required in inferior, posterolateral, or lateral ventricular walls and the gastroepiploic artery graft was too short to cover these areas, we used the composite grafting technique. RESULTS: There were no in-hospital deaths and there was no severe morbidity among the study patients. Postoperative angiography showed graft occlusion at the anastomosis site between the gastroepiploic and radial arteries. The patency rate of the gastroepiploic arterial composite graft was 98.3% (118/120 distal anastomoses). CONCLUSIONS: A composite graft with the skeletonized gastroepiploic artery and the radial artery ensured sufficient caliber size and length for myocardial revascularization on inferior, posterolateral, and lateral ventricular walls. This composite graft can be used safely and effectively even in off-pump coronary bypass surgery with excellent early clinical and angiographic outcome in selected patients, although longer follow-up periods are necessary to draw definitive conclusions.

Aged↗

PubMed2003

Hard labour: bacterial infection of the skeleton.

The skeleton is the largest mammalian organ system, containing a myriad of blood vessels, tissue surfaces and bone cells for bacterial colonization. Although rock-like, the skeleton is a dynamic structure that is undergoing constant remodelling. This is the result of the opposing actions of two key cells: the osteoblast, which produces bone, and the osteoclast, a multinucleate cell that 'eats' bone. It is not generally realized that the most prevalent chronic bacterial diseases of Homo sapiens afflict the skeleton. Several pathogens, and members of the normal microbiota, have evolved specific cellular and molecular mechanisms for invading bone, including its cellular constituents. The host cellular pathways that are activated and lead to destruction or loss of the bone matrix will be described.

Animals↗

PubMed2005

Roles for fgf8 signaling in left-right patterning of the visceral organs and craniofacial skeleton.

Laterality is fundamental to the vertebrate body plan. Here, we investigate the roles of fgf8 signaling in LR patterning of the zebrafish embryo. We find that fgf8 is required for proper asymmetric development of the brain, heart and gut. When fgf8 is absent, nodal signaling is randomized in the lateral plate mesoderm, leading to aberrant LR orientation of the brain and visceral organs. We also show that fgf8 is necessary for proper symmetric development of the pharyngeal skeleton. Attenuated fgf8 signaling results in consistently biased LR asymmetric development of the pharyngeal arches and craniofacial skeleton. Approximately 1/3 of zebrafish ace/fgf8 mutants are missing Kupffer's vesicle (KV), a ciliated structure similar to Hensen's node. We correlate fgf8 deficient laterality defects in the brain and viscera with the absence of KV, supporting a role for KV in proper LR patterning of these structures. Strikingly, we also correlate asymmetric craniofacial development in ace/fgf8 mutants with the presence of KV, suggesting roles for KV in lateralization of the pharyngeal skeleton when fgf8 is absent. These data provide new insights into vertebrate laterality and offer the zebrafish ace/fgf8 mutant as a novel molecular tool to investigate tissue-specific molecular laterality mechanisms.

Animals↗

PubMed2006

Tgfbr2 regulates the maintenance of boundaries in the axial skeleton.

Previously, we showed that deletion of the TGF-beta type II receptor (Tgfbr2) in Type II Collagen (Col2a) expressing cells results in defects in the development of the axial skeleton. Defects included a reduction in size and alterations in the shape of specific vertebral elements. Anterior lateral and dorsal elements of the vertebrae were missing or irregularly shaped. Vertebral bodies were only mildly affected, but the intervertebral disc (IVD) was reduced or missing. In this manuscript, we show that alterations in the initiation or proliferation of cartilage are not detected in the axial skeleton. However, the expression domain of Fibromodulin (Fmod), a marker of the IVD, was reduced and the area of the future IVD contained peanut agglutinin (PNA) staining cartilage. Next, we show that the expression domains of Pax1 and Pax9, which are preferentially expressed in the caudal sclerotome, are expanded over the entire rostral to caudal length of the sclerotome segment. Dorsal-ventral patterning was not affected in these mice as accessed by expression of Pax1, Pax9, and Msx1. Proliferation was modestly reduced in the loose cells of the sclerotome. The results suggest that signaling through Tgfbr2 regulates the maintenance of boundaries in the sclerotome and developing axial skeleton.

Animals↗

PubMed2002

Effects of skeletonization on intraoperative flow and anastomosis diameter of internal thoracic arteries in coronary artery bypass grafting.

BACKGROUND: We examined the hypothesis that complete skeletonization of an internal thoracic artery (ITA) results in increased diameter of the graft for anastomosis and therefore improves graft flow in coronary artery bypass grafting. METHODS: We studied 65 consecutive patients who underwent coronary artery bypass grafting, in which the left ITA was anastomosed to the left anterior descending artery. The first 20 consecutive ITA were harvested as a pedicle (group P) and later 45 consecutive ITAs were harvested as an ultrasonically skeletonized graft (group S). Intraoperative ITA graft mean flows were obtained with a transit-time flowmeter. Three diameters of the ITA graft were measured quantitatively in postoperative angiograms performed 14 +/- 5 days after the coronary artery bypass grafting; D1, at the origin from the subclavian artery; D2, at the level of the second intercostal space; and D3, just proximal to the anastomosis. RESULTS: Intraoperative mean flow was significantly greater in group S than in group P (S: 42.6 +/- 29.1 mL/min versus P: 26.4 +/- 16.1 mL/min, p = 0.03). Although the diameters D1 and D2 were not significantly different between groups, D3 was significantly larger in group S than in group p (S: 1.77 +/- 0.28 mm versus P: 1.57 +/- 0.17 mm, p = 0.02). CONCLUSIONS: Compared with pedicle harvesting, complete skeletonization of ITA may make it possible to anastomose an ITA with a larger diameter in coronary artery bypass grafting, which leads to increased graft flow by decreasing vascular resistance.

Aged↗

PubMed1999

Bilateral internal mammary artery grafting: midterm results of pedicled versus skeletonized conduits.

BACKGROUND: To increase the number of anastomoses per patient, bilateral internal mammary arteries (BIMAs) were harvested with a skeletonized approach instead of a pedicled one. METHODS: One thousand one hundred forty-six patients underwent isolated myocardial revascularization using BIMAs, 304 receiving pedicled grafts (group A, October 1991 through May 1994) and 842 receiving skeletonized conduits (group B, June 1994 through June 1998). Group B had a higher incidence of patients with diabetes (223 versus 40, p < 0.001). RESULTS: The number of BIMA anastomoses per patient was significantly higher in group B (2.4 +/- 0.3 versus 2.1 +/- 0.4, p < 0.001), as well as the number of sequential grafts (288 versus 42, p < 0.001). Twenty-three patients (2.0%) died in the first 30 days after surgery, 5 in group A (1.6%) and 18 in group B (2.1%) (not significant). Postoperative complications were similar in both groups; the incidence of sternal wound healing problems was higher as a whole and with regard to diabetic patients (4 of 40 [10%] versus 5 of 223 [2.2%], p < 0.05) in group A. Seventy-one patients in group A and 133 (15.8%) in group B underwent a postoperative angiography. Patency rate was similar, both early (100% in group A versus 98.6% in group B, not significant) and late (98.6% in group A versus 98.4% in group B, not significant). CONCLUSIONS: The use of skeletonized BIMA conduits allowed us to increase the number of BIMA anastomoses per patient with a lower rate of sternal wound complications and angiographic results similar to those obtained with pedicled BIMA conduits.

Aged↗

PubMed1999

Routine use of bilateral skeletonized internal mammary arteries for myocardial revascularization.

BACKGROUND: Complete arterial myocardial revascularization without the use of saphenous veins grafts was primarily performed on selected patient populations such as the young and nondiabetic. In a recently developed surgical technique, the internal mammary artery is dissected gently as a longer skeletonized artery, providing greater versatility for complete arterial revascularization, without saphenous veins grafts. METHODS: We prospectively evaluated the impact of the routine use of double skeletonized internal mammary artery in 472 patients who underwent coronary artery bypass grafting between April 1996 and June 1997. Their average age was 65 years (30 to 87 years), 383 (83%) were men, and 89 (17%) women. One hundred sixty-nine (36%) of the patients were older than 70 years, and 145 (31%) were diabetic. The average number of grafts was 3.2 per patient (two to six grafts). RESULTS: Operative mortality was 1.7% (n = 8). The mortality of urgent and elective patients was 0.7% (3 of 410 patients), and that of emergency operations was 8.1% (5 of 62 patients; p < 0.01). There were three (0.6%) perioperative infarcts, and 6 patients (1.3%) sustained strokes. Sternal wound infection occurred in 8 patients (1.7%). Postoperative follow-up (1 to 25 months) was available in 462 patients (99%). Two-year actuarial survival was 96.8%, and 92% of the surviving patients are well and free of angina. Neither diabetes mellitus nor old age (>70 years) were significant independent predictors of any early or late untoward events. None of the 70 diabetic patients more than 65 years of age developed sternal wound infection. Chronic lung disease was found to be the only independent predictor for sternal infections. CONCLUSIONS: Routine use of bilateral skeletonized internal mammary artery is a safe replacement for the current myocardial revascularization technique even in the old and diabetic patients.

Adult↗

PubMed2002

Sustained activation of MEK1-ERK1/2 pathway in membrane skeleton occurs dependently on cell adhesion in megakaryocytic differentiation.

A human megakaryoblastic cell line, CMK, was treated with 12-o-tetradecanoylphorbol-13-acetate (TPA) for differentiation-induction. We examined TPA-induced activation of the MEK1-ERK1/2 pathway in the 100,000g Triton X-insoluble fraction of CMK cells as the membrane skeleton and researched the relation of the MEK1-ERK1/2 activation with integrin expression. We found that this activation was divided into two phases: the first activation occurred transiently in the membrane skeleton fraction of the suspended cell status and diminished after 1h; and the second sustained activation was maintained by cell adhesion. TPA-treated CMK cells revealed increased expression of integrins alphaIIb and beta3 only when the cell adhesion persisted, regardless of the difference of culture substratum. Sustained activation of the MEK1-ERK1/2 pathway is generated in the membrane skeleton by continuous cell adhesion and seems to be essential to TPA-induced megakaryocytic differentiation of CMK cells.

Butadienes↗

PubMed1994

Surface shape change during fusion of erythrocyte membranes is sensitive to membrane skeleton agents.

We previously reported that the induction of membrane fusion between pairs of erythrocyte ghosts is accompanied by the formation of a multipore fusion zone that undergoes an area expansion with condition-dependent characteristics. These characteristics allowed us to hypothesize substantial, if not major, involvement of the spectrin-based membrane skeleton in controlling this expansion. It was also found that the fusion zone, which first appears in phase optics as a flat diaphragm, has a lifetime that is also highly condition-dependent. We report here that 2,3-diphosphoglycerate, wheat germ agglutinin, diamide, and N-ethylmaleimide, all known to have binding sites primarily on skeleton components (including spectrin), have condition-dependent effects on specific components of the fusion zone diameter versus time expansion curve and the flat diaphragm lifetime. We also report a pH/ionic strength condition that causes a dramatic stabilization of flat diaphragms in a manner consistent with the known pH/ionic strength dependence of the spectrin calorimetric transition, thus further supporting the hypothesis of spectrin involvement. Our data suggest that the influence of the membrane skeleton on cell fusion is to restrain the rounding up that takes place after membrane fusion and that it may have variable, rather than fixed, mechanical properties. Data show that WGA, a known ligand for sialic acid, and DPG, a known metabolite, influences the flat diaphragm stability and late period expansion rates, raising the possibility that some of these mechanical properties are biologically regulated.

2,3-Diphosphoglycerate↗