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Lipid vesicles (liposomes) containing pH-sensitive fluorophores were used as probes for the study of liposome entry and intracellular fate. Pyranine [8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS)] was entrapped in the liposome aqueous core during preparation to provide a means of detecting internalization into living cells. HPTS is highly water soluble and shows a strong pH-dependent shift in its fluorescence excitation spectrum. Fluorescence emission (FEM) is slightly pH dependent with excitation (lambda EX) at 350-415 nm but highly pH dependent with lambda EX at 450 nm. Liposomes bearing a net negative charge bound rapidly to CV-1 cells and underwent endocytosis. One hour after liposome addition, high FEM with lambda EX at 413 nm and low FEM with lambda EX at 450 nm suggest that most cell-associated liposomes had been internalized and resided at a mean pH of approximately 6.6. Collapse of cellular H+ gradients with NH4Cl or monensin treatment rapidly and reversibly increased FEM with lambda EX at 450 nm. Direct examination by fluorescence microscopy corroborates the fluorometric data on internalization; over time, FEM remained high with lambda EX at 350-405 nm but decreased with lambda EX at 450-490 nm, showing that all lipid vesicles were internalized within 40 min at 37 degrees C. Acidification of intracellular liposomes increased over 3 h, reaching a minimum value of approximately pH 5.5. HPTS persisted within acidic cellular vesicles for 2-3 days, and cytoplasmic dye was observed infrequently, suggesting that liposome fusion with cellular membranes seldom occurs. Material delivered to the endocytic pathway via lipid vesicles labeled an assortment of intracellular organelles of varying motility and morphology, including dynamic tubular structures whose lumen is acidic.
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PMID:Endocytosis and intracellular fate of liposomes using pyranine as a probe. 216 72

Cor pulmonale is a common complication and frequent cause of death in COLD. No published records are as yet available on the prognostic ranking of two-dimensional echo-cardiography in this group of patients. In 79 of 85 (93%) consecutively echocardiographically examined COLD patients it was possible to effect apical imaging of the four-chamber view to assess the size of the right ventricle, as well as a subcostal imaging to analyse the respiratory performance of the vena cava inferior (vci). Among the exclusion criteria of this prospective series were a diseased condition of the left heart or other associated cardiac diseases. The patients were classified into two risk groups (RG 0 and RG 1) depending upon whether they had a normal-sized right ventricle or a complete inspiratory collapse of the vci, or not. In RG 1 the pO2 values were lower (56.8 +/- 9.2 vs 66.0 +/- 8.8 mmHg, p less than 0.0005) whereas the values for the respiratory passage resistance were higher (8.01 +/- 3.92 vs 6.22 +/- 2.87 cm H2O/l/s; p less than 0.025) than with RG 0, the values for the intrathoracic gas volume not being significantly different from each other. Fatal cardiopulmonary results were covered over a period of 2-48 months (median 24 months) to perform life table analyses according to Breslow and Mantel. Patients with an enlarged right ventricle or incomplete respiratory collapse of the vci have a lower survival rate (43.7% respectively 61.9%) than patients with a normal-size right ventricle or complete respiratory collapse of the vci (90.5% respectively 88%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Prognosis in cor pulmonale: predictive value of two-dimensional echocardiography]. 221 91

Perioperative hemodynamic changes of hemodialysed patients were investigated and the changes of emergency cases (group E, n = 8) were compared with those of scheduled ones (group S, n = 13). By preoperative hemodialysis (HD), the values of blood urea nitrogen, serum creatinine, serum potassium, serum bicarbonate, and hematocrit were adjusted within normal range in group E, with no significant difference from those of group S. On the other hand, concerning the effect of preoperative removal of body water by HD, cardio-thoracic ratio (CTR, 53.6 +/- 3.1%) and pulmonary artery diastolic pressure (PADP, 11.6 +/- 5.0 mmHg) of group E were significantly higher than those of group S (CTR = 46.9 +/- 4.5%, PADP = 7.8 +/- 3.0 mmHg), indicating that the removal of body water by preoperative HD might be less in group E. However, group E patients required more administration of fluid and pressor agents in order to maintain their blood pressure and/or cardiac output during operation. Although with less water removal preoperatively and more fluid intraoperatively, postoperative PADP was significantly reduced (8.3 +/- 3.0 mmHg) in group E, suggesting that the requirement of perioperative water is more in group E. We conclude that the safe perioperative hemodynamic management for emergency surgery of hemodialysed patients requires following points; (1) The excessive removal of body water by preoperative HD should be avoided. (2) Intraoperative fluid infusion should be adequate so that they do not fall into hemodynamic collapse.
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PMID:[Perioperative hemodynamic changes and management of hemodialysed patients]. 224 11

The influence of calcium ions on the electrophoretic properties of phospholipid stabilized emulsions containing various quantities of the sodium salts of oleic acid (SO), phosphatidic acid (SPA), phosphatidylinositol (SPI), and phosphatidylserine (SPS) was examined. The critical flocculation concentration of calcium corresponded to a critical zeta potential in all but one of the systems. Systems of approximately equal zeta potential in 0 mM Ca++ had different zeta potentials in dilute solutions of Ca++. A comparison of emulsions of similar polydispersity suggests that these differences may be largely related to differences in particle size and surface area of the emulsions. The influence of Ca++ on the monolayer properties of mixed films containing phosphatidylcholine (PC) with either SPA or SO was also examined at the air-water interface. Films containing PC with SPA were more expanded on a subphase containing calcium compared to a subphase with no calcium. In addition, the compression of films containing PC with SO demonstrated two collapse pressures while SPA was relatively more miscible in the film. This suggests that phase separation of interfacial lipids occurs more easily in systems containing PC and SO. These results may help to explain differences in the flocculation and coalescence of emulsions stabilized by lipid films of different composition.
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PMID:The influence of charged lipids on the flocculation and coalescence of oil-in-water emulsions. II: Electrophoretic properties and monolayer film studies. 225 Feb

To prevent their collapse, a certain amount of stiffness is generally required for prosthetic venous grafts, so EPTFE grafts have been used. However, the native vein is pliable without any stiffness. We developed a soft and pliable graft that can maintain patency of the lumen because of its compliance. Fresh porcine ureter was incubated in a ficin solution to remove cell components and noncollagenous proteins. One percent protamine sulfate solution was injected into the ureter lumen to impregnate the inner surface. The ureter was then crosslinked with a 1% glutaraldehyde solution, dipped into a 1% heparin solution for 5 hours, and rinsed with distilled water. This procedure made the ureter very soft and pliable, and also conferred antithrombogenicity to the graft by heparinization. The grafts were implanted into the posterior vena cavae of 20 dogs and were removed from 1 to 878 days after implantation. Eighteen grafts were patent, but two grafts were occluded at the anastomotic site at 218 and 107 days, respectively. As a control experiment, nonheparinized grafts were implanted into 15 dogs; all were occluded with fresh thrombi. All the patent grafts kept their original elasticity, which allowed them to heave in unison with the heartbeat, and were similar in appearance to the native vena cava. Heparinization was effective in preventing thrombus formation. These results indicate that this type of graft is an ideal prosthesis as a venous graft, having physiologic properties such as compliance and antithrombogenicity.
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PMID:Development of a soft, pliable, slow heparin release venous graft. 225 94

Transient cavitation is a discrete phenomenon that relies on the existence of stabilized nuclei, or pockets of gas within a host fluid, for its genesis. A convenient descriptor for assessing the likelihood of transient cavitation is the threshold pressure, or the minimum acoustic pressure necessary to initiate bubble growth and subsequent collapse. An automated experimental apparatus has been developed to determine thresholds for cavitation produced in a fluid by short tone bursts of ultrasound at 0.76, 0.99, and 2.30 MHz. A fluid jet was used to convect potential cavitation nuclei through the focal region of the insonifying transducer. Potential nuclei tested include 1-microns polystyrene spheres, microbubbles in the 1- to 10-microns range that are stabilized with human serum albumin, and whole blood constituents. Cavitation was detected by a passive acoustical technique that is sensitive to sound scattered from cavitation bubbles. Measurements of the transient cavitation threshold in water, in a fluid of higher viscosity, and in diluted whole blood are presented. These experimental measurements of cavitation thresholds elucidate the importance of ultrasound, host fluid, and nuclei parameters in determining these thresholds. These results are interpreted in the context of an approximate analytical theory for the prediction of the onset of cavitation.
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PMID:Thresholds for transient cavitation produced by pulsed ultrasound in a controlled nuclei environment. 226 22

1. The three typical cases reported above were syncopic patients of different types. Case 1 belonged to yin-depletion syndrome, case 2 pertained to yang-depletion syndrome, and case 3 Jue syndrome due to disturbance between qi and the blood induced by deficiency of qi and accumulation of phlegm. All of the three cases were satisfactorily cured with acupuncture and moxibustion though they did not respond to western medicines. 2. The rationale of acupuncture treatment for syncope includes: 1) Regulating yin and yang: For yin-depletion syndrome, reinforcing method is mainly adopted for nourishing water to promote reproduction of the body fluids and replenishing yin to restore yang; in case of yang-depletion syndrome, moxibustion and needle-warming methods are mainly used for recuperating the depleted yang to rescue the patient from collapse and for invigorating yang to restore yin. 2) Resuscitating the patient by regulating qi and the blood and dredging the channels to activate the circulation. After a successful resuscitation, the patient should be radically treated with appropriate herbal medicines so as to consolidate the therapeutic efficacy. 3. An emergency treatment for syncopal patients with acupuncture and moxibustion must be based on a conscientious differentiation of the signs and symptoms. The treatment should strictly follow the therapeutic principles: reinforce for the deficiency, reduce for the excess, cool the heat and warm the cold.
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PMID:Acupuncture treatment of syncope based on differentiation of signs and symptoms. 227 15

Between October 6, 1986 and September 17, 1987, 11 patients underwent insertion of mandibular dental prostheses by the same oral surgeon. Three patients suffered cardiac arrest during surgery and subsequently died. Two of the patients who died had received general anaesthetics and the other had intravenous sedation given by three different anaesthetists. All three patients arrested suddenly, developing profound cyanosis and electrical mechanical dissociation, underwent prolonged resuscitative efforts, and had marked hypoxaemia and hypercapnia, despite cardiopulmonary resuscitation. Two other patients had signs of injection of air but survived, one suffering cardiac collapse and the other sustaining massive subcutaneous emphysema. Air embolism was produced by inadvertent injection of a mixture of air and water, passing through the hollow dental drill, directly into the mandible to the facial and pterygoid plexus veins and thence to the superior vena cava and right atrium.
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PMID:Fatal air embolism during dental implant surgery: a report of three cases. 227 34

A combination of cimetidine, diphenhydramine, and ibuprofen has been shown to be an effective treatment in a porcine model of septic acute lung injury. The present study was designed to evaluate this therapy in a delayed treatment survival model. Three groups of animals were studied: a control group (C, n = 6) received a sham infusion of 0.9% saline; a septic group (Ps, n = 5) received a continuous infusion of live Pseudomonas aeruginosa organisms; and a treatment group (CID, n = 6) received P. aeruginosa plus cimetidine 150 mg, ibuprofen 12.5 mg/kg, and diphenhydramine 10 mg/kg given at 90 min after P. aeruginosa infusion, and hourly thereafter. Group Ps developed fulminant acute lung injury and hypodynamic septic shock. CID therapy ameliorated temporarily the progressive course of hypoxemia and increased extravascular lung water (EVLW), delayed the onset of cardiovascular deterioration, and improved significantly survival time. It was concluded that CID therapy given at 90 min after the onset of lethal continuous P. aeruginosa infusion improved significantly animal survival time by improving temporarily hypoxemia and increase in EVLW and delaying cardiovascular collapse.
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PMID:Increased survival time after delayed histamine and prostaglandin blockade in a porcine model of severe sepsis-induced lung injury. 230 57

The enzyme rhodanese (EC 2.8.1.1) could be reversibly refolded from urea in the presence of lauryl maltoside, beta-mercaptoethanol, and sodium thiosulfate. The unfolding/folding transition monitored using intrinsic fluorescence was resolved into two two-state transitions with midpoints at 3.6 and 5.0 M urea. The analysis assumed an intermediate with an emission maximum at 345 nm. Monitoring anisotropy of intrinsic fluorescence also gave an asymmetric transition. Activity followed one two-state transition centered at 3.6 M urea with no major change of secondary structure. Without thiosulfate or mercaptoethanol, there was one two-state transition at 5.0 M urea giving a species, in dilute urea, with a fluorescence maximum at 345 nm. This intermediate slowly relaxed toward 335 nm (t1/2 = 85 min) if only thiosulfate was absent but without regaining activity. Subsequent addition of thiosulfate led to a first-order recovery of activity (t1/2 = 75 min). Thus, a possible folding intermediate can be trapped which displays increased access of water and solutes to its fluorescent tryptophans. This intermediate conformer, which is flexible, has considerable secondary structure, is inactive, has exposed hydrophobic surfaces, and requires specific reducing conditions to regain full activity. Refolding probably involves an initial, rapid, hydrophobic collapse with acquisition of secondary structure to form the intermediate, followed by slower adjustment to the native global conformation. Final reactivation requires reduction localized at the active site.
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PMID:Stable intermediates can be trapped during the reversible refolding of urea-denatured rhodanese. 230 16


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