Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0344329 (collapse)
 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the roles of eicosanoid mediators in acute systemic anaphylaxis in anesthetized sheep. Sheep were sensitized with dinitrophenylated Ascaris suum extract and were challenged with an intravenous injection of dinitrophenylated bovine serum albumin. During anaphylaxis, cyclooxygenase inhibitors eliminated the elevation of arterial plasma levels of thromboxane B2 and 6-ketoprostaglandin F 1 alpha but markedly elevated the levels of leukotriene E4 in lung lymph without significantly eliminating elevation of plasma levels of histamine. Most of the measured physiological abnormalities accompanying anaphylaxis were aggravated by cyclooxygenase blockade. Enhancement of this anaphylactic mediator response was associated with an accentuated and prolonged increase of airway pressure (P less than 0.05, compared with sensitized, antigen-challenged but otherwise untreated sheep), a more intense hypoxemia (P less than 0.0001), and leukopenia (P less than 0.001), changes that were largely eliminated by pretreating with the sulfidopeptide leukotriene (SPLT) antagonist FPL 55712, suggesting that the SPLTs were important mediators of these responses. In contrast, the prolonged, but less severe, systemic vascular collapse and the reduced pulmonary hypertension induced by cyclooxygenase inhibitors were not influenced by the SPLT antagonist. These results demonstrate that in sheep cyclooxygenase metabolites are mainly involved in the acute, but transient, systemic and pulmonary vascular response of systemic anaphylaxis, whereas SPLTs are primarily implicated in the airway and secondary cardiovascular response. SPLT may act either directly or by potentiating the release of and reactivity to histamine and other mediators. Our data therefore suggest that a combination of cyclooxygenase and lipoxygenase inhibition will be necessary to more effectively protect against the consequences of an anaphylactic reaction.
 ...
PMID:Leukotrienes, thromboxane A2, and prostaglandins during systemic anaphylaxis in sheep. 171 64

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.
 ...
PMID:Thresholds for transient cavitation produced by pulsed ultrasound in a controlled nuclei environment. 226 22

We attempted to ascertain the mechanism of portal hypertension and ascites complicating acute hepatitis in 66 patients who underwent transvenous liver biopsy and measurement of hepatic venous pressure gradient. Increase in hepatic venous pressure gradient was related to the severity of acute hepatitis, as indicated by the significant correlation between the values for hepatic venous pressure gradient and serum bilirubin, serum albumin or coagulation factor V, and by its higher value in patients with, than in patients without, encephalopathy. Hepatic venous pressure gradient was higher in patients with, than in patients without, ascites (12.5 +/- 3.4 vs. 8.4 +/- 3.6 mmHg, respectively; p less than 0.001). No ascites was clinically detectable in the patients in whom hepatic venous pressure gradient was below 6 mmHg. We tested the hypothesis that sinusoidal collapse due to liver cell dropout was a major factor in portal hypertension. Semiautomatic determination of the fractional area of sinusoidal collapse on chromotrope-stained sections and automatic measurement of Sirius red-stained collagen fiber density were performed. Hepatic venous pressure gradient significantly correlated with fractional sinusoidal collapse area (r = 0.61, p less than 0.001) and with Sirius red-stained collagen fiber density (r = 0.43, p less than 0.01). We conclude that portal hypertension in the course of acute hepatitis is related to the severity of liver damage and is a major factor in the development of ascites. Portal hypertension is mainly determined by intrahepatic vascular space being reduced by the collapse of sinusoids.
 ...
PMID:Portal hypertension and ascites in acute hepatitis: clinical, hemodynamic and histological correlations. 277 10

The effect of adriamycin aglycones on Ca2+ retention by isolated, preloaded rat heart mitochondria was assessed. After an initial lag, which decreased with increasing drug concentration, the 7-hydroxy-aglycone (5-20 microM) triggered Ca2+ release. Aglycone-induced Ca2+ release was correlated with Ca2+-dependent mitochondrial swelling, Ca2+-dependent collapse of the mitochondrial membrane potential, Ca2+-dependent oxidation of mitochondrial pyridine nucleotides, and a transition from the condensed to the orthodox configuration. Aglycone-induced Ca2+ release was inhibited by dibucaine, dithiothreitol, ATP, and bovine serum albumin. It can be concluded, therefore, that aglycone-induced Ca2+ release reflects the Ca2+-dependent increase in the permeability of the inner mitochondrial membrane to solutes of molecular weight less than 1000 which has been observed with other triggering agents [R. A. Haworth and D. R. Hunter, Archs Biochem. Biophys. 195, 460 (1979); I. Al-Nasser and M. Crompton, Biochem. J. 239, 19 (1986)]. In particular, the 7-hydroxy-aglycone decreased the amount of Ca2+ required to trigger the permeability increase. No effect of the aglycone on Ca2+ uptake could be discerned. 7-Deoxy-adriamycin aglycone, the more prominent biological metabolite of adriamycin, was similarly effective in inducing Ca2+ release, and both aglycones were substantially more effective than the parent drug. Adriamycin and related anthracyclines are potent antineoplastic agents, the clinical use of which is limited by severe cardiotoxicity. These results suggest that aglycone formation and the resultant disruption of both cellular Ca2+ homeostasis and metabolite compartmentation may mediate anthracycline cardiotoxicity.
 ...
PMID:Na+-independent release of Ca2+ from rat heart mitochondria. Induction by adriamycin aglycone. 334 98

The case notes and radiographs of 108 patients who had undergone compression screw fixation of trochanteric fractures of the femur were reviewed. Forty-seven patients had unstable comminuted fractures, and 20 of these had medial displacement osteotomies performed. In 40% of this group the operation was not a success in terms of extrusion of the screw through the femoral head, compared with 20% for the whole series of 108 patients. A number of parameters were studied in the search for a cause for the failure, and there was a correlation with a superior position of the screw initially, and a low serum albumin. Although the proximal fragment abutted the plate at the time of operation, the medial cortices of the proximal and distal fragments were often not in apposition, allowing the fracture to collapse into varus with resultant extrusion. Unless a stable configuration is achieved at the time of operation, reliance on the sliding component of these implants to allow for collapse at the fracture site will not necessarily produce this stability, and failure will ensue.
 ...
PMID:Sliding hip screws and medial displacement osteotomy. 335 55

We prepared ten dogs with intraperitoneal catheters to allow total nutritional support for 30 days by constant infusion of a solution containing 1.5% amino acid, 10% glucose, and 1% lipids at a rate of 4 ml/kg/hr. Seven dogs survived in apparent good health but with a 13.9 +/- 1.3% weight loss. There was no correlation between actual caloric input and percentage of weight loss. Serum albumin concentration fell to 2.6 +/- 0.3 gm/dl but other chemistries remained near normal. The peritoneum showed significant inflammatory reaction but this resolved by 30 days. Three dogs died in the first week from what appeared to be circulatory collapse from rapid fluid shifts. We conclude that a significant amount of nutrients can be delivered through the peritoneal cavity but whether total nutritional support is feasible remains to be proven.
 ...
PMID:Total nutritional support through the peritoneal cavity. 393 May 90

Experimental data on surface pressure-surface area hysteresis of mixed serum albumin/dipalmitoyl lecithin/sphingomyelin monolayers in the Langmuir trough are presented. Several possible physicochemical mechanisms of the hysteresis are discussed: Marangoni effect, surface pressure relaxations, bulk-to-surface diffusion interchange, and collapse. Depending on the concrete conditions each of these mechanisms can be important. Possible applications of these results to the alveolar dynamics are presented and discussed on the basis of the balloon model of the alveolus. The main conclusions of biological importance are that 1) the alveolar stability depends on the DPL/SM ratio as well as on the protein content. Under normal breathing conditions the surface pressure hysteresis is small and does not play a decisive role in the alveolar dynamics. 2) At large extent of compression the collapse predominates in determining the hysteretic behavior of the alveolar surface.
 ...
PMID:Surface pressure hysteresis of mixed lipid/protein monolayers: applications to the alveolar dynamics. 654 92

Patients requiring long term intensive care and/or prolonged ventilatory support, are frequently undergoing progressive malnutrition, occasionally complicated by a hypercatabolic state. Sepsis, fever and the requirements for postoperative healing will add further nutritional demands on such patients. In contrast to starvation, critically ill patients maintained on protein-free energy-deficient diet do not adapt to utilization of their lipid to provide energy needs. Mobilization of endogenous fat stores is reduced, and this reduction leads to increased gluconeogenesis from amino acids derived from muscle protein to meet the increased energy needs. Low serum albumin, possible low surfactant production, devitalization of the alveolo-capillary membrane and impaired immunocompetence could contribute to the development of pulmonary transudation, alveolar collapse, low compliance and pulmonary infection. Such sequelae of a protein-free energy-deficient diet would delay weaning patients off prolonged mechanical ventilation. Nutritional assessment, which may be determined serially, and means of nutritional support are outlined.
 ...
PMID:Nutritional support in long term intensive care with special reference to ventilator patients: a review. 678 7

Four groups of six nonimmune male rhesus monkeys were inoculated subcutaneously with formulations of dengue type 2 vaccine virus DEN-2/S-1. Group A received 1.9 x 10(4) plaque-forming units of vaccine in normal human serum albumin diluent. Group B received the same dose combined with a dengue type 2-immune human serum diluted 1:1,600, beyond its neutralization endpoint of 1:300, but having an immune enhancement titer of 250,000. Groups C and D received 10-fold dilutions of these respective formulations. No migration-inhibitory factor was found when peripheral blood mononuclear leukocytes obtained on day 68 post-immunization from monkeys of all experimental groups were tested. No viremia was detected in any of the monkeys when sera taken on postvaccination days 1 through 12 were inoculated into adult Toxorhynchites amboinensis mosquitoes and LLC-MK2 cells. By day 89, four of the six monkeys had seroconverted by the neutralization test in each of groups A, B, and C, and three of five monkeys in group D (one monkey died from cardiac collapse after anesthesia) had seroconverted. Immune enhancement of dengue virus infection is known to occur in humans and monkeys circulating heterologous flavivirus antibodies. In this study, there was no enhancing effect when antibody was mixed with dengue type 2 vaccine virus and injected subcutaneously.
 ...
PMID:Lack of greater seroconversion of rhesus monkeys after subcutaneous inoculation of dengue type 2 live-virus vaccine combined with infection-enhancing antibodies. 702 29

The addition of bovine serum albumin (BSA) to 25 +/- 5 nm diameter single bilayer phosphatidylcholine (PC) vesicles (SBV) (pH 3.5) gives rise to readily visible transient turbidity. Studies of this system, employing a series of techniques, including time-dependent turbidity changes, membrane filtration, centrifugation, Sepharose chromatography and freeze fracture electron microscopy demonstrated that the process involves aggregation and fusion of the vesicles. At least three distinct time-dependent steps have been characterized: (1) the rapid initial formation (in approx. 5 min) of large aggregates (responsible for the visible turbidity) composed of SBV interconnected by BSA in its F form. The formation of these aggregates may be reversed by raising the pH or adding excess BSA to the system at this stage; (2) spontaneous collapse of these large aggregates, in an irreversible step, to form a heterogeneous population of vesicles; (3) fusion produces as the final product of the process, a relatively homogeneous population of larger (50 +/- 10 nm diamter) vesicles. This system serves as a convenient and simple model system for the detailed study of protein-mediated aggregation and fusion of membranes at the molecular level.
 ...
PMID:A kinetic and structural study of two-step aggregation and fusion of neutral phospholipid vesicles promoted by serum albumin at low pH. 719 54


1 2 3 4 5 6 7 Next >>