Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012739 (disseminated intravascular coagulation)
 8,673 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastric parietal cells in primary culture have been tested to determine their utility as a model for the study of the role of intracellular calcium ([Ca2+]i) in the control of HCl secretion. Changes in [Ca2+]i were measured in single cells on a microscope stage using the cell-permeant form of the fluorescent calcium probe, fura-2. Simultaneous images of cell fluorescence and morphology were acquired using a digitized video image analysis system and two video cameras, one for low-light level fluorescence detection and one for high resolution DIC/transmitted light images. Both histamine and carbachol, which are known stimulants of HCl secretion, increased [Ca2+]i and stimulated dramatic changes in morphology in these cultured cells. Changes in morphology were accompanied by an increased uptake of the weak base, [14C]-aminopyrine (AP), and a shift from green to red fluorescence of another weak base, acridine orange. These results indicate that cultured parietal cells, maintained under controlled conditions on a microscope stage, retain viability and secretagogue responsiveness. Thus, this cellular model appears to be suitable for correlation of changes in [Ca2+]i and activation of HCl secretion.
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PMID:HCl secretion and [Ca2+]i in cultured parietal cells. 238 25

Methods for the study of axons involve whole nerve preparations, teased preparations of axons that are excised from their proximal and distal connections, and tissue culture models. As a complement to these, it would be advantageous to study separated, isolated axons in vivo, still in continuity with the end organ distally and the spinal cord central nervous system neuron proximally. This would allow the study of axon function, normal or pathological, in a close relationship to its biological environment. To achieve this, we have passed the surgically isolated sciatic nerve of a rat through a chamber specially designed for enzymatic dissociation. This was based on principles derived from a prior in vitro method for dissociating nerve into axons. The chamber has controlled temperature and flow and is on an inverted microscope stage, allowing observation of the process. We perfused the chamber with a calcium-free solution followed by a series of enzymes: collagenase, trypsin, and hyaluronidase. This dissociates that part of the extracellular matrix external to the Schwann cells, leaving free, myelinated axons with their Schwann cells. In this acute preparation, the axons continue to conduct action potentials for at least 8 hours. Furthermore, an in vitro study of the axon after the in vivo dissociation demonstrated that axonal transport was maintained in over 90% of the axons, directly visualized on an AVEC-DIC type of microscope system. Properties of axonal transport or active spike propagation can thus be studied individually in an in vivo axon preparation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Model for the study of individual mammalian axons in vivo, with anatomical continuity and function maintained. 241 87

Preparations yielding a high percentage of undamaged axons from fresh peripheral nerve or nerve root were made using an enzymatic dissociation regimen. The nerve was placed in a temperature-controlled chamber mounted over an inverted phase-contrast microscope. An oxygenated solution (Brimijoins) or modified Hank's solution was pumped through the chamber, first in a calcium-free form and then containing enzymes. The enzymes for dissociation were collagenase and trypsin, alternated. Enzymatic dissociation of the epineurium, perineurium and extracellular matrix was achieved. We supplemented the gentle agitation of a 10-roller peristaltic pump by periodically raising and lowering the fluid level in the chamber to provide a controlled mechanical agitation that promoted dissociation. A large percentage of the axons can be dissociated from the nerve, varying from approximately one-quarter to occasional complete dissociation. Action potentials were still conducted through dissociated axons, and axon transport was also still present, as documented by direct visualization using an AVEC-DIC type of microscope system. The axons had a better morphological appearance and displayed better transport than comparison preparations prepared by the usual mechanical teasing method, in our hands. The enzymatic method allows study of axons in an adult or developing mammal with regard to their electrical conduction and axon transport mechanisms. It should help to avoid a selection process for more hardy axons which may be imposed by traditional mechanical teasing methods. Mechanical stress was observed to cause widened Schmidt-Lanterman clefts, widened nodes, myelin bubbles, and other abnormal morphology as evidence of damage.
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PMID:A method for in vitro enzymatic dissociation of nerve roots and peripheral nerves from adult mammals. 241 9

In vivo fragmentation of the von Willebrand factor antigen (vWF:Ag) molecule has been demonstrated on radiocrossed immunoelectrophoresis (CIE) in the plasma from patients with disseminated intravascular coagulation, in factor VIII concentrates, and in normal serum. Experiments reported here show that polymorphonuclear (PMN) cells contain a non-calcium-dependent protease(s) that when released and incubated with vWF:Ag results in an additional vWF:Ag peak on radio-CIE. Production of fragments of vWF:Ag by incubation with PMN cells occurred in a time-dependent manner. The protease(s) responsible was inhibited by diisopropyl fluorophosphate, soybean trypsin inhibitor, and aprotinin, but not by benzamidine, azide, epicron, or hirudin. Citrate, EDTA, and leupeptin also had no effect on the PMN cell enzyme's activity, indicating that the enzyme(s) is not calcium dependent. The PMN cell enzyme responsible for vWF:Ag fragmentation is located intracellularly and released by freezethaw lysis or cell activation by calcium or the calcium ionophore A23187.
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PMID:Proteolytic cleavage of human von Willebrand factor induced by enzyme(s) released from polymorphonuclear cells. 242 5

The development of AVEC-DIC microscopy and the application of this method to the study of fast axonal transport in isolated axoplasm extruded from the giant axon of the squid Loligo pealei provides a new paradigm for analyzing the intracellular transport of membranous organelles. The size of the axon, the number of transported particles, and the absence of permeability barriers like the plasma membrane in this preparation permit many experiments that are difficult or impossible to perform using other model systems. The use and features of this preparation are described in detail and a number of properties are evaluated for the first time. The process of extrusion is characterized. Particle movement is evaluated both in the interior of extruded axoplasm and along individual fibrils that extend from the periphery of perfused axoplasm. The role of divalent cations, particularly Ca2+, and the effects of elevated Ca2+ on axoplasmic organization and transport are analyzed. A series of pharmacological agents and polypeptides that alter cytoskeletal organization are used to examine the role of microfilaments and microtubules in fast transport. Finally, the effects of depleting ATP and of adding ATP analogues are discussed. The extruded axoplasm preparation is shown to be an invaluable model system for biochemical and pharmacological analyses of the molecular mechanisms of intracellular transport.
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PMID:Video microscopy of fast axonal transport in extruded axoplasm: a new model for study of molecular mechanisms. 258 Jun 32

A new platelet aggregating protein (PAP) was purified from the plasma of a patient with acute thrombotic thrombocytopenic purpura (TTP) using A1 (OH)3 adsorption, PEG fractionation, DEAE cellulose chromatography, lentil lectin Sepharose 4B chromatography and gel filtration HPLC. The M. W. of this PAP was estimated to be 59,000. It induced the aggregation of washed platelets from normal subjects and the same patient after recovery. The antigenic material was present in 2 out of 6 other TTP patients but was absent in 7 normal subjects, two patients with DIC and two patients with ITP. The aggregation of washed platelets by PAP was concentration dependent and required energy metabolism, Ca2+ and fibrinogen. PAP was present in the plasma of a subset of TTP patients and was likely the cause of platelet thrombi in the microvessels in these patients.
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PMID:[Purification and some properties of platelet aggregating protein (PAP) from the plasma of a patient with thrombotic thrombocytopenic purpura]. 259 93

Patients with chronic myeloproliferative disorders (CMPD) frequently have abnormalities of plasma von Willebrand factor (vWf) multimers. The pathogenesis of this phenomenon is still unknown. In order to evaluate the possibility of ex vivo degradation of vWf during blood processing, we compared vWf antigen, ristocetin cofactor and the multimeric composition of vWf in plasmas obtained in the presence of trisodium citrate with or without calcium-dependent protease inhibitors (leupeptin, N-ethylmaleimide and Na2EDTA). The subjects included 20 patients with CMPD, 11 with other diseases and 8 normal subjects. In patients with CMPD and normal subjects, the values of vWf antigen, ristocetin cofactor, ristocetin cofactor/vWf antigen ratio and the relative amount of large multimers of vWf did not significantly differ from each other in plasma samples with and without protease inhibitors. In other diseases, especially in a patient with disseminated intravascular coagulation, a somewhat higher amount of large multimers were found in plasma with protease inhibitors than without inhibitors. These findings indicate that the ex vivo proteolysis during blood processing is negligible in patients with CMPD, and that the observed abnormalities in vWf is an in vivo phenomenon.
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PMID:Plasma von Willebrand factor proteolysis in patients with chronic myeloproliferative disorders: no possibility of ex vivo degradation by calcium-dependent proteases. 269 24

Selective reduction in multiple gestation refers to abortion of specific fetuses, either because of congenital defect of grand multiple gestation. Fetal indications for which selective termination has been reported are Down syndrome, microcephaly, hemophilia A, spina bifida, thalassemia major and Tay-Sachs disease. Grand multiple gestations, defined as 4 or more fetuses in a pregnancy, have been selectively terminated in cases of 4-9 fetuses. Most couples choose to reduce multiple gestations to twin pregnancies. Very short women with multiple gestation are particularly at risk. Methods used have included needle aspiration of amniotic fluid, cardiac puncture and aspiration, and intrathoracic injection of KC1 or calcium gluconate. Potassium chloride is preferred because it is rapid, so results can be determined immediately without having to repeat the procedure. It is preferable to time the termination at 11 weeks' gestation to lower the risk of disseminated intravascular coagulation, which can result from absorption of fetal tissue. Most gynecologists prefer to select for fundal implantations. The ethical alternatives of this type of termination are either to abort the entire pregnancy, or risk the life of the mother as well as the life and well-being of all the fetuses. Most women with multiple gestations are those with history of infertility, who have gone to greater expense and emotional investment to become pregnant. Legally, selective reduction is a type of 1st trimester abortion, subject to institutional experimental protocols and patient's informed consent.
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PMID:Selective reduction in multiple gestation. 273 40

We previously reported that calcium entry blockers (CEBs) protected against endotoxin-induced mortality in rats. In this investigation, the i.v. injection of endotoxin (ETX) in control awake male Wistar rats was found to produce pathophysiological changes indicative of disseminated intravascular coagulation (DIC). The latter included increased serum fibrin (ogen) degradation products (FDP), decreased plasma fibrinogen, reduced blood platelet count as well as microscopic findings of fibrin microthrombi in small blood vessels of visceral organs. Gross pathological examination revealed pronounced hemorrhagic congestion of the gastrointestinal tract and petechial and ecchymotic hemorrhages in other visceral organs. Pretreatment with the CEBs, nilvadipine (FR 34235) and nitrendipine, inhibited the elevation in serum FDP and decrease in plasma fibrinogen but did not prevent the thrombocytopenia produced by ETX. The gross pathological manifestations of DIC were also inhibited by pretreatment with the CEBs. The results suggest that the protective effect of CEBs against endotoxin-induced mortality in rats may be related to inhibition of DIC caused by the lipopolysaccharide.
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PMID:The effects of the calcium entry blockers, nilvadipine and nitrendipine, on endotoxin-induced disseminated intravascular coagulation. 279 86

Allen Video-enhanced contrast/differential interference contrast (AVEC-DIC) microscopy was used in conjunction with video intensification immunofluorescence microscopy to demonstrate that organelles and vesicle (particles) can move in either direction along microtubular linear elements in fibroblasts [Hayden et al., 1983]. Since it is not possible to determine the number of microtubules making up a linear element with light microscopy alone, AVEC-DIC microscopy was used in conjunction with whole-mount electron microscopy to show bidirectional transport along a single microtubule [Hayden and Allen, 1984]. These studies demonstrate that the structural polarity of the microtubule does not determine the direction of particle motion, and since dynein is an asymetric molecule, a simple microtubule-dynein-particle hypothesis cannot explain bidirectional transport along a single microtubule. Very little is known about regulation of particle transport in most cell types. Human embryonic lung fibroblasts grown on glass coverslips were serum-deprived for 24 hours and re-fed with serumless medium; the particle translocations/5 minutes were then determined. The cells were then re-fed with either serumless medium, serum-containing medium, or serumless medium containing some bioactive factor, and the particle translocations/5 minutes were again determined for the same cells. Medium containing 10% fetal bovine serum inhibited particle translocation by 51.8%. Of the bioactive factors tested, only vasopressin produced a significant reduction in particle translocations (38%). This suggests that protein kinase C or calcium/calmodulin kinase could be involved in regulating particle transport.
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PMID:Microtubule-associated organelle and vesicle transport in fibroblasts. 318 Feb 46


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