Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027947 (neutropenia)
 17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intravascular complement activation in rats following thermal injury or vascular infusion of cobra venom factor results in acute lung injury as determined morphologically and measured by increases in lung vascular permeability. The acute lung injury is associated with the early appearance of C5-derived chemotactic activity in the circulation coincident with the development of neutropenia. The lung injury is closely linked to availability of complement and neutrophils and can be prevented by systemic treatment of animals with a combination of superoxide dismutase and catalase, specific inhibitors of toxic oxygen metabolites. These data suggest that intravascular complement activation leads to activation of neutrophils and their intrapulmonary capillary sequestration, and subsequent acute lung injury, which is associated with production and release of oxygen-derived free radicals by C5a-activated blood neutrophils.
 ...
PMID:Lung injury secondary to chemotactic factor-induced leukocyte activation. 634 Apr 40

After 14 days' bone marrow maturation, neutrophil granulocytes reach the tissues where for 1-2 days they form the army whose phagocytic function was described by llya Metchnikoff in 1882. At that time, Paul Ehrlich was developing his neutrophil secretory theory which had less success until it returned with a vengeance in the last decade. Neutrophils are not only phagocytes. Above all they are cells that secrete bactericidal effectors and regulators (amplifiers and modulators) of the inflammatory focus. More and more sophisticated methods are being used to study phagocytosis, from the point of view both of the mechanism of chemotaxis and its role in inflammation and of the mediators of oxygen-dependent bactericidal action (superoxide anion, oxygenated water, hydroxyl radicals, myeloperoxidase, halogen ions and superoxide dismutase). In addition, the importance of oxygen-independent bactericidal mechanisms has been confirmed by the discovery of proteins such as BPI (Bactericidal Permeability Increasing Protein). Study of neutrophil dysfunction throws light on a number of neutrophil regulatory and effector mechanisms; it also proves useful in explaining the recurrent infections observed in some congenital disorders (chronic granulomatous disease, the "lazy leucocyte syndrome", the Chediak-Higashi syndrome, ichthyrosis , Job's syndrome...) or those associated with transitory neutrophil disorders (measles, severe bacterial infection...). Neutropenia induced by some antibiotics is easily demonstrated, but the interactions between these antibiotics and neutrophils are complex: phagocyte concentration of antibiotic, neutrophil inactivation of antibiotic, effect of antibiotic on microbe-leucocyte interaction such as an alteration in phagocytic and chemotactic response. The neutrophil is the first blood cell to arrive at the inflammatory focus; it is also at the centre of the response, next to the humoral mediators which both act upon it and which it itself secretes.
 ...
PMID:[Neutrophil functions and interactions in the inflammatory reaction]. 673 54

The fall in white blood cells (WBC) and arterial oxygen pressure that occurs during hemodialysis was investigated as a function of different dialysis membranes and different sterilization methods. 8 chronic hemodialysis patients were studied and each was dialyzed with three different membranes: cellulosic hollow fiber, polyacrylonitrile flat sheet and polymethylmethacrylate hollow fiber. Each dialyzer was studied with a dry sterilization method and after formalin treatment. Arterialized blood gas, bicarbonate and WBC were drawn at various intervals throughout dialysis. The effect of the sterilization method was minimal. Cellulosic membranes were shown to cause significantly more neutropenia (p less than 0.001) and hypoxemia (p less than 0.01) than the other two membranes. No significant differences was seen in pH, PCO2 and bicarbonate. The results indicate differences in biocompatibility between different membranes. Clinical implications are discussed.
 ...
PMID:Hemodialysis-associated neutropenia and hypoxemia: the effect of dialyzer membrane materials. 681 50

Acute thermal injury (70 degrees C, 30 sec) to rat skin results in progressive consumptive depletion of the complement system. Individual complement components (C3, C4, C6) each show reductions in hemolytic activity. Crossed immunoelectrophoresis analysis of serum from thermally injured rats reveals conversion of C3 compatible with activation of the complement system. During the first hour following thermal injury, C5a-related chemotactic activity appears in the serum and is temporally related to the development of neutropenia. Lung injury, as revealed by increases in lung permeability, develops progressively during a 6-hour period and parallels changes in complement levels. Morphologically, lung changes include leukoaggregates within pulmonary capillaries and the presence of intra-alveolar hemorrhage. Protection from lung injury following remote thermal injury to skin is afforded by depleting animals of complement or neutrophils, or by systemic treatment of animals with a combination of catalase and superoxide dismutase. Antihistamine drugs have no protective effect. These data suggest that acute thermal injury leads to systemic complement activation, neutrophil activation, and acute lung injury that is related to production of toxic oxygen products by activated blood neutrophils.
 ...
PMID:Oxygen radical dependent lung damage following thermal injury of rat skin. 684 28

Exposure of human blood polymorphonuclear leukocytes (PMN) to purified active plasma kallikrein resulted in PMN aggregation when kallikrein was present at concentrations ranging from 0.4 to 0.6 U/ml (0.18-0.27 microM). Kallikrein-induced PMN aggregation was not mediated through C5-derived peptides, because identical responses were observed whether or not kallikrein had been preincubated with an antibody to C5. Moreover, kallikrein was specific for aggregating PMN, because no aggregation was observed with Factor XII active fragments (23 nM), Factor XIa (0.6 U/ml or 15nM), thrombin (1.6 microM), plasmin (2 microM), porcine pancreatic elastase (2 microM), bovine pancreatic chymotrypsin (2 microM), or bradykinin (1 microM). Bovine pancreatic trypsin (2 microM) aggregated PMN, but to a lesser extent than kallikrein (0.18 microM). Kallikrein was a potent aggregant agent for PMN because similar responses were observed with kallikrein (0.5 U/ml or 0.23 microM) and an optimal dose (0.2 microM) of N-formyl-methionyl-leucyl-phenylalanine. In addition, PMN incubation with kallikrein resulted in stimulation of their oxidative metabolism as assessed by an increased oxygen uptake. Neutropenia and leukostasis observed in diseases associated with activation of the contact phase system may be the result of PMN aggregation by plasma kallikrein.
 ...
PMID:Purified human plasma kallikrein aggregates human blood neutrophils. 691 55

It has been suggested that neutrophil (PMN) specific granules are important in cell aggregation, locomotion, hydroxyl radical formation, and in extracellular functions such as the generation of complement-related inflammatory mediators (C5a) and the feedback regulation of myelopoiesis. In the current studies, a 9-yr-old boy with a history of recurrent infections and specific granule deficiency (absent lactoferrin, B-12 binding proteins, and characteristic specific granules on sucrose gradient centrifugation of cell homogenates) was studied to assess some of these concepts. In vivo, the patient had decreased PMN and monocyte accumulation into Rebuck skin windows but an expected febrile episode with an associated neutropenia (PMN margination) and neutrophilia (mobilization of marrow reserves) in response to intravenous endotoxin. In vitro, the patient's resting PMN showed increased ruffling, increased surface-to-volume ratio, and increased numbers of centriole-associated microtubules. His PMN showed a significant decrease in cell negative surface charge (which may relate to aggregation) in response to several stimuli and adhered better than normally to plastic. In addition, his PMN aggregated normally in response to the chemoattractant f-met-leu-phe, although the subsequent disaggregation normally seen with PMN did not occur with the patient's cells. Chemotaxis of the patient's PMN to several stimuli was abnormal, and specific saturable and displaceable binding of the chemoattractant f-met-leu-[3H]phe was decreased. Similarly, following incubation with secretagogues, there was a less than normal increase in f-met-leu-[3H]phe binding and an absence of the normal increases in PMN surface area. The patient's PMN bactericidal activity, stimulated oxygen metabolism (cytochrome-c reduction, chemiluminescence, and NBT reduction), and elicited changes in membrane potential were also abnormal. Studies assessing the mechanism for the abnormal monocyte accumulation into skin windows indicated the patient's monocyte chemotaxis was better than normal in vitro. However, the patient's PMN homogenates lacked a stimulus of monocyte locomotion and did not generate chemotactic activity normally from serum. Thus, the data indicate that specific granule constituents are not required for neutrophil margination in vivo or aggregation in vitro. However, the data support the concept that PMN-specific granules are important for PMN locomotion and oxidative metabolism. In addition, extracellular release of specific granule constituents appears to be important for amplification of the initial and subsequent phases of the inflammatory response.
 ...
PMID:Human neutrophil-specific granule deficiency: a model to assess the role of neutrophil-specific granules in the evolution of the inflammatory response. 704 47

Intravascular activation of the complement system with cobra venom factor results in acute lung injury, which has been quantitated by increases in lung vascular permeability. Cobra venom factor preparations devoid of phospholipase A2 activity retain full lung-damaging capacity. The lung injury is associated with the preceding appearance of chemotactic activity in the serum coincident with the development of a profound neutropenia. The chemotactic activity is immunochemically related to human C5a. Morphologic studies have revealed discontinuities in the endothelial cell lining of lung alveolar capillaries, damage and/or destruction of endothelial cells in these areas, plugging of pulmonary capillaries with neutrophils that are in direct contact with vascular basement membrane, the presence of fibrin in alveolar spaces and in areas adjacent to damaged endothelial cells, and intraalveolar hemorrhage. Lung injury is dramatically attenuated in animals that have been previously neutrophil depleted. Teh intravenous injection of superoxide dismutase or catalase also provides significant protection from the pulmonary damage. Very little protection from the pulmonary damage. Very little protection is afforded by pretreatment of rats with antihistamine. These studies suggest that intravascular activation of the complement system leads to neutrophil aggregation and activation, intrapulmonary capillary sequestration of neutrophils, and vascular injury, which may be related to production of toxic oxygen metabolites by complement-activated neutrophils.
 ...
PMID:Intravascular activation of complement and acute lung injury. Dependency on neutrophils and toxic oxygen metabolites. 706 50

L-selectin requirements in three models of acute lung injury in rats have been identified: systemic activation of complement after intravenous infusion of cobra venom factor (CVF) and intrapulmonary deposition of IgG or IgA immune complexes. In the CVF model of lung injury, treatment of rats with hamster monoclonal IgG anti-rat-L-selectin (HRL-1) induced significant neutropenia, necessitating the use of F(ab')2 fragments, which did not cause neutropenia. Treatment of rats with F(ab')2 anti-L-selectin (HRL-1) resulted in significant reductions in lung permeability and hemorrhage in the CVF model. Morphologically, this treatment abrogated adhesive interactions of neutrophils with the pulmonary vascular endothelium. In the IgG immune complex model of injury, the parameters of injury were significantly reduced as a result of treatment with HRL-1. In both models protection was associated with reductions in lung myeloperoxidase content. Treatment of rats with a F(ab')2 form of hamster monoclonal IgG non-blocking anti-L-rat selectin, HRL-2, failed to show protective effects in the CVF and IgG immune complex models of lung injury. In the IgA immune complex model of injury, which is neutrophil-independent and related to toxic products from pulmonary macrophages, no protective effects of anti-L-selectin (HRL-1) were found. Therefore, in neutrophil-dependent and oxygen radical mediated lung injury, L-selectin plays a requisite role in tissue recruitment of neutrophils. In the neutrophil-independent model of lung injury, no requirement for L-selectin appears to exist.
 ...
PMID:Requirements for L-selectin in neutrophil-mediated lung injury in rats. 750 37

A 61-year-old male with acute promyelocytic leukemia (APL) had been in complete remission for the previous 15 months, but his APL relapsed with neutropenia. Although promyelocytes in bone marrow were reduced after administration of 60 mg all-trans retinoic acid (ATRA) daily, myelocytes were predominant on the myelogram and neutropenia did not recover. By adding 75 micrograms of granulocyte colony-stimulating factor (G-CSF) daily, neutrophils accounted for 35.0-55.5% of the myelogram, and the peripheral neutrophil count rose dramatically. Such morphological differentiation of myeloid series was also ascertained in terms of their functions of both neutrophil alkaline phosphatase activity and active oxygen producing capacity. This case supports the concept that G-CSF accelerates ATRA-induced neutrophilic differentiation of blast cells in APL.
 ...
PMID:The combined effects of all-trans retinoic acid and granulocyte colony-stimulating factor as a differentiation induction therapy for acute promyelocytic leukemia. 750 72

It has been previously demonstrated that the administration of recombinant human granulocyte-colony stimulating factor (rhG-CSF) ameliorates the decrease of the polymorphonuclear neutrophils (PMNs) count after the cytotoxic chemotherapies, thereby reducing the infection complications associated with neutropenia. In this multi-center study, we studied the prophylaxtic effect of rhG-CSF administration on infection complications in patients with non-Hodgkin malignant lymphoma, who received cytotoxic chemotherapies (CHOP or ProMACE/CytaBOM). rhG-CSF administration reduced the frequency of infection complications, and there was no obvious difference in it's frequency between the CHOP-treated and the ProMACE/CytaBOM-treated groups when administered with rhG-CSF, thereby indicating that third generation therapy for NHL may be safely completed in Japanese in combination with rhG-CSF administration. Furthermore, we investigated both the in vitro and the in vivo effects of rhG-CSF on the function of PMNs in patients with NHL and healthy donors, and revealed that the administration of rhG-CSF for NHL patients receiving cytotoxic chemotherapy brought on an improvement of the production of active oxygen but did not affect serum levels of IFNs, IL-1-beta, and IL-6, inspite of a slight elevation of TNF-alpha. Consistent with these results, in vitro treatment of PMNs with rhG-CSF induced no significant production of these inflammatory cytokines and their mRNA expressions. Furthermore, rhG-CSF administration showed no significant effects in vivo on the expression of CD11a, CD11b and LECAM-1 on PMNs and integrins on platelets.
 ...
PMID:Effects of rhG-CSF on infection complications and impaired function of neutrophils secondary to chemotherapy for non-Hodgkin's lymphoma. Hokkaido Study Group of Malignant Lymphoma, and rhG-CSF, Japan. 754 Apr 62


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>