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At least 991 records · Page 55Linked to original sources
PubMed1998

Inhibition of bone resorption in vitro by a peptide containing the cadherin cell adhesion recognition sequence HAV is due to prevention of sealing zone formation.

Cadherins are transmembrane glycoproteins usually mediating homophilic calcium-dependent cell-cell adhesion in a variety of cells and species. All classical cadherins share common structural and functional properties, one of which is the cell adhesion recognition (CAR) sequence HAV (His-Ala-Val). In the present work we have studied the effects of the cadherin CAR sequence-containing hexapeptide AHAVSE on osteoclasts, the main bone resorbing cells in well-characterized pit formation assay. The primary attachment of osteoclasts to bone surface is not affected by the peptide, suggesting that it is not mediated by cadherins. However, treatment of osteoclast cultures with AHAVSE peptide decreased the number of resorption pits and the total resorbed area without affecting the mean size of resorption pits. Furthermore, we show rapid inactivation of osteoclasts with AHAVSE, which is seen as a decrease in the percentage of osteoclasts with actin rings. Double staining of pan-cadherin antibody with actin and vinculin localized cadherin-like molecule in the sealing zone area of osteoclasts. These results suggest that the tight attachment of osteoclasts to the bone surface in the sealing zone area may be mediated by cadherin-like molecules and that the decrease of resorption in AHAVSE-treated osteoclast cultures is due to prevention of sealing zone formation.

Actins↗
PubMed1985

Midbody sealing after cytokinesis in embryos of the sea urchin Arabacia punctulata.

Cytokinesis consists of a contractile phase followed by sealing of the connecting midbody to form two separated cells. To determine how soon the midbody sealed after cleavage furrow contraction, the fluorescent dye Lucifer Yellow CH(457.3 M.W.) was microinjected into cells at various intervals after cleavage had begun. Mitotic PtK2 cells were recorded with video-microscopy so that daughter cells in the epithelial sheet could be identified for several hours after cell division. One daughter cell of each pair followed was microinjected to determine whether the dye diffused into the other daughter cell. For intervals up to four hours after the beginning of cytokinesis, diffusion took place between daughter cells. After this time the dye did not spread between daughter cells. In sea urchin blastomeres of the first, second and third divisions, Lucifer Yellow passed between daughter blastomeres only during the first 15 min after cytokinesis. If one cell of a two-cell, four-cell or eight-cell embryo was microinjected more than 15 min after the last cleavage, the dye remained in the injected cell and was distributed to all progeny of that cell, resulting in blastulae that were eigher one-half, one-quarter or one-eighth fluorescent, respectively. Thus, although cleavage furrow contraction takes approximately the same amount of time in sea urchin blastomeres and PtK2 cells, the time of midbody sealing differs dramatically in the two cell types. Our results also indicate the importance of knowing the mitotic history of cells when injecting dyes into interphase cells for the purpose of detecting gap junctions.

Animals↗
PubMed1991

GTP gamma S causes contraction of skinned frog skeletal muscle via the DHP-sensitive Ca2+ channels of sealed T-tubules.

We have investigated the involvement of G-proteins in excitation-contraction coupling of fast-twitch skeletal muscle, using a fibre preparation designed to retain intact T-tubules and sarcoplasmic reticulum. The nonhydrolysable analogue of guanosine triphosphate, GTP gamma S (50-500 microM) caused a strong, transient isometric contraction in this preparation. Reduction of ethylene-bis(oxonitrilo)tetraacete (EGTA) in the sealed T-tubules from 5 mM to 0.1 mM lowered the threshold to GTP gamma S and removal of sodium reversibly raised it. The dihydropyridine (DHP) calcium channel antagonists nicardipine and nifedipine allowed a first contraction and then blocked subsequent GTP gamma S action. The phenylalkylamine methoxyverapamil (D-600) did likewise, reversibly, at 10 degrees C. The guanosine diphosphate analogue, GDP beta S, and procaine reversibly blocked the action of GTP gamma S; pertussis toxin also blocked it. Photolytic release of 40-100 microM GTP gamma S within 0.1 s from S-caged GTP gamma S caused contraction after a latent period of 0.3-20 s. We conclude that GTP gamma S can activate contraction in frog skeletal muscle via a route requiring both the integrity of the T-tubular DHP-sensitive calcium channel (DHPr) and the presence of sodium in the sealed T-tubules. We propose that in this preparation GTP gamma S activates a G-protein, which in turn activates the DHPr as a calcium channel and releases stored calcium from within the sealed T-tubule. Implications of these results for the excitation-contraction coupling mechanism in skeletal muscle are discussed.

Animals↗
PubMed1991

Inhibiting synthesis of extracellular matrix improves patch clamp seal formation.

The ability to form gigaohm seals is essential for patch-clamp studies. Cells with otherwise useful properties must be abandoned for electrophysiological studies if seal formation is not possible. We have found that by inhibiting the growth of extracellular matrix with beta-D-xyloside, the success of forming gigaohm seals increased from near 0% to near 100%. Treated cells remained viable and appeared morphologically similar to untreated cells. Prototype treatment protocols are given for the renin secreting cell line As4.1.

Animals↗
PubMed1994

Facilitated giga-seal formation with a just originated glass surface.

A simple technique of tip preparation in patch pipettes is described, which facilitates giga-seal formation. The pipettes were fabricated from thick-walled borosilicate glass tubing (external diameter 2.0 mm, internal diameter 0.5 mm) and the tips could be repeatedly broken in the bath. The pipette resistance correspondingly fell in steps of 3-20 M omega from about 80 M omega to about 2 M omega (double concentrated Tyrode). Scanning electron microscopy showed that the tip obtained after breaking was fairly plain. These broken tips were especially appropriate for patch-clamping. In cardiac myocytes in 11 out of 26 patches with Na+ channel activity, giga-seals developed spontaneously, i.e. without suction. In these patches the amplitude of the mean current with depolarizing pulses to -40 mV was significantly higher in comparison with patches formed under negative pressure. It is concluded that spontaneously sealed patches are most likely of planar configuration and the Na+ channel activity exceeds that in suction-induced patches.

Animals↗
PubMed2003

[Vacuum sealing of extensive wound healing disorders after kidney transplantation].

With the introduction of mycophenolate mofetil (MMF) in renal transplantation, acute rejection episodes diminished and short-term graft survival improved. Better graft outcome, however, is followed by several surgical complications attributed to MMF. Patients with risk factors (adiposity, diabetes mellitus, advanced age) show an increased rate of healing by second intention. We treated two patients with the vacuum sealing technique so that after 15 days a secondary suture became possible in each case. To date the vacuum sealing technique has been used mainly in traumatology, abdominal surgery, surgery for acute infections of soft tissue and bone, and problem wounds with reduced wound-healing capacity (chronic leg ulcer). This article presents two cases of successful application of the vacuum sealing technique in renal transplantation after prolonged wound healing.

Body Mass Index↗
PubMed2006

Incidence of vascular injuries after use of the Angio-Seal closure device following endovascular procedures in a single center.

INTRODUCTION: Percutaneous closure devices have been used to obtain rapid hemostasis and early mobilization of the patient after arterial catheterization. However, we observed challenging problems with the sealing procedure that require further surgical intervention. The present report is a retrospective analysis of the patterns of injury and the final outcome of four cases of femoral artery injury following the use of Angio-Seal. METHODS: During the last 24 months, in a group of 175 patients (131 men, 44 women; median age 68.4 years, range 47-81 years) underwent percutaneous closure after diagnostic (n = 53) or therapeutic (n = 122) endovascular procedures. Among them we observed four patients (three men, one woman; median age 65.2 +/- 10.8 years, range 47-75 years) who developed severe limiting claudication and required vascular repair of an iatrogenic vascular injury following deployment of the Angio-Seal. They had a femoral thrombosis due to narrowing/severe intimal dissection. RESULTS: All patients required operative intervention with removal of the device. We performed femoropopliteal thrombectomy and common femoral endarterectomy with patch angioplasty (n = 2), resection of the femoral bifurcation and reimplantation of the deep femoral artery (n = 1), and femoral bifurcation endarterectomy with direct arterial suture (n = 1). The median hospital stay was 6.5 +/- 3.8 days (range 4-12 days). Limb salvage was achieved in all of the surviving patients at a mean follow-up of 7 months (range 1-12 months). CONCLUSIONS: Vascular injuries are uncommon after use of the hemostasis closure device. When they occur, however, they are likely to require challenging surgical correction.

Aged↗
PubMedDate not supplied

Treatment of acute lower limb ischemia following the use of the Duett sealing device: report of three cases and review of the literature.

Three cases of local thrombolysis in the treatment of acute lower limb ischemia complicating the utilization of the Duett sealing device are presented. Routine usage of several vascular closure devices after cardiac catheterization and percutaneous coronary intervention (PCI) has been adopted in our institution during the last 3 years (September 1999 to April 2003). The Duett closure device has been used in 420 patients (post-coronary angiography, 359; post-PCI, 61). Three patients (0.7%) demonstrated acute leg ischemia used by inadvertent intravascular administration of the sealing material related to this device. All three were treated successfully by catheter-directed local thromolysis (tissue plasminogen activator 5 mg bolus followed initially by 1 mg/hr and consequently by 0.5-1.0 mg/hr depending upon the development of significant hematoma and lasting for 24 hr). In conclusion, interventional treatment using local thrombolysis should be the first-line treatment in acute lower limb ischemia complicating the utilization of the Duett sealing device.

Acute Disease↗
PubMed2001

Excimer laser-assisted recanalisation of femoral arterial stenosis or occlusion caused by the use of Angio-Seal.

The aim of this study was to demonstrate the effect of excimer laser and balloon angioplasty of femoral artery stenosis and occlusion after use of a haemostatic puncture closure device. A haemostatic puncture closure device (Angio-Seal) was used in 6000 patients after diagnostic or therapeutic artery catheterisation. In 34 of those patients symptoms of peripheral artery disease occurred. Sixteen of those 34 cases were transferred to our clinic for excimer laser angioplasty. All 16 patients presented with symptoms of acute peripheral artery disease within 1-14 days: superficial femoral artery (SFA) occlusions (4 cases); superficial femoral artery stenosis (3 cases); high-grade stenosis of the common femoral artery (CFA; 3 cases); high-grade stenosis of CFA; SFA and profund femoral artery (PFA; 3 cases); and occlusions of CFA, SFA and PFA (3 cases). Before any procedure was performed, informed consent was given by the patient, which included the use of the Angio-Seal closure device. Every patient who had to undergo recanalisation procedures gave additional informed consent which especially included the usage of the excimer laser for recanalisation. A measurement of the walking distance, ankle-brachial systolic pressure index (ABI) and diagnostic angiography was performed in 13 cases before and immediate after as well as 3 and 6 months after therapeutic percutaneous transluminal laser angioplasty followed by balloon angioplasty (PTLA/PTA). In 3 patients the risks of PTLA/PTA was considered too high; those patients underwent surgical repair. Angiographic and clinical improvement was achieved in 13 of 13 patients. The mean walking distance increased from 81 to > 400 m. The average ankle-brachial systolic pressure index (ABI) increased from 0.47 to 0.84. One patient developed a dissection of the SFA, and in 1 case a peripheral embolisation was seen. The PTLA/PTA technique is a successful therapeutic option for patients with femoral artery occlusion or high-grade stenosis after Angio-Seal application.

Angioplasty, Balloon, Laser-Assisted↗
PubMed2006

A longitudinal and cross-sectional analysis of total body oxygen store development in nursing harbor seals (Phoca vitulina).

This study compared the efficacy of longitudinal and cross-sectional sampling regimes for detecting developmental changes in total body oxygen (TBO(2)) stores that accompany behavioral development in free-ranging harbor seal pups. TBO(2) stores were estimated for pup (n = 146) and adult female (n = 20) harbor seals. Age related changes were compared between pups captured repeatedly during the lactation period (longitudinal dataset) and a second group of pups handled only once (cross-sectional dataset). At each handling, hematocrit, hemoglobin, red blood cell count, total plasma volume, blood volume, muscle myoglobin concentration, and blood and muscle oxygen stores were determined. Comparisons across age categories revealed newborn blood oxygen stores were initially elevated, declined to low values by early lactation, and increased through post-weaning. Muscle oxygen stores remained low and constant throughout lactation and only increased significantly post-weaning. Overall TBO(2)stores increased 17% during lactation, and weaned pups had TBO(2)stores that were 55% as large as those of adults. Thus, significant increases in TBO(2) stores must occur after weaning, as pups begin to forage independently. Results from the two sampling schemes did not differ, indicating that the logistically simpler cross-sectional design can be used to monitor physiological development in harbor seals.

Animals↗
PubMed2002

A new bipolar feedback-controlled sealing system for closure of the cystic duct and artery.

BACKGROUND: Bile leaks are serious complications after laparoscopic cholecystectomy. The aim of this study was to evaluate the feasibility of closure of the cystic duct with a new feedback-controlled bipolar sealing system (LigaSure). METHODS: Ten domestic pigs underwent open cholecystectomy with the cystic duct and artery dissected and sealed with the new bipolar sealing system (LigaSure). Four and 8 days postoperatively, 5 pigs each were sacrificed and the closure of the cystic duct was evaluated. The cystic stump and the common bile duct were excised for histological examination. RESULTS: None of the pigs had a bile leak or a biliary peritonitis. There were no signs of postoperative bleeding or inflammation in Calot's triangle. Histology showed total necrosis of the cystic duct in the first two pigs due to too much energy used. The remaining specimens showed a regularly scaling zone without necrosis in 7 cases, and in one case a partial necrosis in the mucosa only was found. CONCLUSION: Cystic artery and cystic duct closure with the new device may be an alternative to the clip. Further trials should evaluate the feasibility and safety of the new device in the clinical setting.

Animals↗
PubMed2004

Effect of Endo-GIA vascular staple size on laparoscopic vessel sealing in a porcine model.

BACKGROUND: Two sizes of endoscopic gastrointestinal anastomosis (Endo-GIA) staples are currently available for vascular control. The purpose of this study was to compare the Endo-GIA 30-2.0 mm with the Endo-GIA 30-2.5 mm vascular staple. METHODS: The renal blood vessels, aorta, and vena cava were divided laparoscopically using the Endo-GIA 30-2.0 and 30-2.5 mm in four pigs, respectively. The arterial and venous segments were harvested en bloc for ex vivo burst pressure studies. RESULTS: Both 2.0-mm and 2.5-mm staples achieved vessel sealing at supraphysiologic mean burst pressures (> or =310 mmHg). There were no statistical differences between mean burst pressures of vessels stapled by 2.0-mm compared to 2.5-mm staples. Both staples sealed arteries up to 17 mm and veins up to 22 mm in diameter. CONCLUSION: Endo-GIA 30-2.0 mm and 30-2.5 mm vascular staples are equivalent in sealing vessels at supraphysiologic mean burst pressures.

Anastomosis, Surgical↗
PubMed2004

Sealing effect of fibrin glue on the healing of gastrointestinal anastomoses: implications for the endoscopic treatment of leaks.

BACKGROUND: The adoption of advanced laparoscopic techniques for complex surgical procedures has raised the concern that the leak rate might be higher than for open surgery, particularly in the surgeon's early experience or in difficult cases. In this study, the sealing effect of fibrin glue on leaking gastrointestinal anastomoses was evaluated in an experimental swine model. METHODS: A standardized gastrojejunostomy was performed on 20 female pigs (mean weight, 47.7 +/- 5.7 kg). A leak was created on the anterior surface of the anastomosis. The animals were randomized to either fibrin glue or no treatment of the leak. Clinical conditions and vital signs, including body temperature, heart rate and, respiratory rate, were collected three times a day. Preoperative and postoperative complete and differential blood count and lactate dehydrogenase levels were determined. Postmortem analysis was performed when the animals were killed. RESULTS: Clinical signs of peritonitis developed in the control animals by the second or third postoperative day. Findings that confirmed the presence of an anastomotic leak at the postmortem examination were the presence of food or gastrojejunal juices in the abdominal cavity, a localized abscess, or a positive air leak test. Fibrin glue treatment prevented the development of peritonitis in all the animals. Complete sealing of the leak was observed on postoperative day 7 in all treated animals, except one in which an asymptomatic contained leak developed. The postoperative total white blood count was significantly increased in the untreated group (24.69 +/- 5.5 vs 12.74 +/- 3.7 10(3)/ul p < 0.001, paired t-test), as compared with the treated group (15. 55 +/- 2.4 vs 14.89 +/- 2.7 10(3)/ul; p = 0.24). CONCLUSION: In this study, fibrin glue showed reproducible sealing effects on leaking gastrojejunal anastomoses. Fibrin glue application may be a valuable approach for the treatment of gastrointestinal anastomotic leaks.

Animals↗
PubMed1988

Isolation of sealed plasma membrane vesicles from Phytophthora megasperma f. sp. glycinea. I. Characterization of proton pumping and ATPase activity.

Sealed vesicles were isolated from a plant pathogenic fungus Phytophthora megasperma f. sp. glycinea using a modification of a method previously developed for plant plasma membrane vesicle isolation. Vanadate-sensitive, proton pumping microsomal membrane vesicles were resolved on a linear sucrose density gradient and found to comigrate with a vanadate-sensitive ATPase. Both the proton pumping and ATPase activity of these vesicles had a pH optimum of 6.5 and demonstrated similar properties with respect to substrate specificity and inhibitor sensitivity. These properties were in agreement with previously published data on the Phytophthora plasma membrane ATPase. In contrast with previous reports there was no K+ stimulation of the plasma membrane ATPase and the Km for Mg:ATP (1:1 concentration ratio) was higher (2.5 mM). A comparison of anion (potassium salts) effects upon delta pH and delta psi formation in sealed Phytophthora plasma membrane vesicles revealed a correspondence between the relative ability of anions to stimulate proton transport and to reduce delta psi. The relative order for this effect was KCl greater than KBr much greater than KMes, KNO3, KClO3, K2SO4. This study presents a method for the isolation of sealed vesicles from Phytophthora hyphae. It also provides basic information on the plasma membrane H+-ATPase and its associated proton pumping activity.

Adenosine Triphosphatases↗
PubMed1986

Velocities and stress levels of axisymmetric, azimuthal flow within the toroidal rotary seal of the IBM 2997 continuous flow cell separator and the implications.

Continuous flow blood fraction separators are used to facilitate the removal of specific blood components for donation or for certain medical procedures. Problems with one such device, the IBM 2997 Blood Processor, have been noted in a number of independent investigations. A key feature of this particular unit is a ceramic rotary seal that allows the continuous separation by centrifugation to take place. The equation of motion for flow inside a split toroid cavity within the rotary seal has been solved numerically; velocities and shear stresses found numerically compare favorably with limiting case, analytical solutions. Predicted torque values as a function of rotation rate and fluid viscosity also served as an experimental check on the validity of the mathematical findings. Comparison of calculated shear stress levels and exposure times with known thresholds for cell damage shows that platelet and leukocyte losses may indeed be caused by the seal. Suggestions are made to improve performance of the IBM Blood Processor.

Blood Cells↗
PubMed1975

A study of posterior palatal seals with varying palatal forms.

A study was carried out to determine the depth and width of posterior palatal seals in different shapes of palates. Four different methods of developing the posterior palatal seal were utilized on each patient. The width of the posterior palatal seal area was compared with original models which were produced by plaster impressions.

Dental Impression Materials↗
PubMed1979

Clinical progress of sealed and unsealed caries. Part II: Standardized radiographs and clinical observations.

At the present time, a trend has been shown that the progress of sealed caries is markedly slowed by sealant therapy as compared to open lesions. This fact has been substantiated by depth measurements, viable bacterial counts, standardized radiographs, and clinical observations. The radiographic and clinical observations agreed with the previously reported two parameters in confirming that (1) sealed cavities showed little or no change in depth and (2) open lesions showed a significant increase in depth as compared to sealed lesions.

Child↗
PubMed1980

Posterior peripheral seal distortion related to height of the maxillary ridge.

A statistically significant positive relationship exists between ridge height of a cast and dimensional changes in the posterior peripheral seal region of its denture base. This dimensional change might be clinically insignificant, but it should not be ignored. The relationship between distortion of the denture base and composition of the denture teeth is not significant. The relationship of distortion of the denture base at the region of the posterior peripheral seal and variables of ridge height and tooth composition were studied. A positive relationship exists between ridge height and distortion, but no significant relationship was found between dimensional change and the use of porcelain or acrylic resin teeth. Using computer analysis, an equation, table, and curve were derived for values of expected dimensional change in the posterior peripheral seal region related to various ridge heights.

Acrylic Resins↗