Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During allergic disease, leucocytes infiltrate the affected tissues and release their mediators and cytokines. In this way, the local inflammatory process is induced and maintained. Basophilic granulocytes have been demonstrated in lung and sputum of allergic asthmatics, in nasal mucosa and secretion of allergic rhinitis patients, and in skin lesions of atopic dermatitis patients. The number of basophils correlates with the severity of the disease. Analysis of mediator profiles and cellular contents of lavages of nose, skin and lung during allergic late-phase reactions (LPR) have demonstrated histamine, but not tryptase or prostaglandin D2. The histamine-containing cells have been characterized as basophilic granulocytes. This indicates that infiltrating basophils but not mast cells are activated and release their inflammatory contents in the LPR. We are interested in the cellular mechanisms that determine the degranulation of basophils during LPR. Basophil activators, such as allergens and activated complement, are not present at these sites. However, cytokines that prime basophils but do not induce degranulation, such as interleukin-5 (IL-5) and granulocyte/macrophage colony-stimulating factor (GM-CSF), have been detected at sites of LPR. We have now observed that after emptying intracellular Ca2+ stores by means of the Ca2+ adenosine triphosphatase (ATPase) inhibitor, thapsigargin, basophils become extremely sensitive to stimuli that do not affect the Ca2+ stores themselves but that induce degranulation, such as the phorbolester, phorbol myristate acetate (PMA). The most interesting finding was that although both thapsigargin and IL-3, IL-5 or GM-CSF do not induce basophil degranulation by themselves, a 2 min preincubation of basophils with thapsigargin followed by addition of one of these cytokines resulted in extensive histamine release: IL-3 induced 71 +/- 7% histamine release (conc1/2max 6 pM), IL-5 induced 43 +/- 8% histamine release (conc1/2max 41 pM) and GM-CSF induced 57 +/- 10% histamine release (conc1/2max 140 pM). Interestingly, the effect of thapsigargin could be mimicked by platelet-activating factor (PAF) (range 10(-9) to 10(-6) M), although to a lesser extent. Our results indicate that basophil degranulation in tissues during late-phase reactions might be caused by a combination of mediators or cytokines depleting Ca2+ stores, as platelet-activating factor or thapsigargin do, concurrent with activation by interleukin-3, interleukin-5 or granulocyte/macrophage colony-stimulating factor. The response of the basophils towards these cytokines might also be influenced by cell adhesion events, such as binding of basophils via integrins. This is the subject of further study.
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PMID:The role of basophils in allergic disease. 887 Oct 57

The physicochemical properties of water enable it to act as a solvent for electrolytes, and to influence the molecular configuration and hence the function--enzymatic in particular--of polypeptide chains in biological systems. The association of water with electrolytes determines the osmotic regulation of cell volume and allows the establishment of the transmembrane ion concentration gradients that underlie nerve excitation and impulse conduction. Fluid in the central nervous system is distributed in the intracellular and extracellular spaces (ICS, ECS) of the brain parenchyma, the cerebrospinal fluid, and the vascular compartment--the brain capillaries and small arteries and veins. Regulated exchange of fluid between these various compartments occurs at the blood-brain barrier (BBB), and at the ventricular ependyma and choroid plexus, and, on the brain surface, at the pia mater. The normal BBB is relatively permeable to water, but considerably less so to ions, including the principal electrolytes Brain fluid regulation takes place within the context of systemic fluid volume control, which depends on the mutual interaction of osmo-, volume-, and pressure-receptors in the hypothalamus, heart and kidney, hormones such as vasopressin, renin-angiotensin, aldosterone, atriopeptins, and digitalis-like immunoreactive substance, and their respective sites of action. Evidence for specific transport capabilities of the cerebral capillary endothelium, for example high Na+K(+)-ATPase activity and the presence at the abluminal surface of a Na(+)--H+ antiporter, suggests that cerebral microvessels play a more active part in brain volume regulation and ion homoeostasis than do capillaries in other vascular beds. The normal brain ECS amounts to 12-19% of brain volume, and is markedly reduced in anoxia, ischaemia, metabolic poisoning, spreading depression, and conventional procedures for histological fixation. The asymmetrical distributions of Na+ K+ and Ca2+ between ICS and ECS underlie the roles of these cations in nerve excitation and conduction, and in signal transduction. The relatively large volume of the CSF, and extensive diffusional exchange of many substances between brain ECS and CSF, augment the ion-homeostasing capacity of the ECS. The choroid plexus, in addition to secreting CSF principally by biochemical mechanisms (there is an additional small component from the extracellular fluid), actively transports some substances from the blood (e.g. nucleotides and ascorbic acid), and actively removes others from the CSF. In contrast with CSF secretion, CSF reabsorption is principally a biomechanical process, passively dependent on the CSF-dural sinus pressure gradient. Pathological increases in intracranial water content imply development of an intracranial mass lesion. The additional water may be distributed diffusely within the brain parenchyma as brain oedema, as a cyst, or as increase in ventricular volume due to hydrocephalus. Brain oedema is classified on the basis of pathophysiology into four categories, vasogenic, cytotoxic, osmotic and hydrostatic. The clinical conditions in which brain oedema presents the greatest problems are tumour, ischaemia, and head injury. Peritumoural oedema is predominantly vasogenic and related to BBB dysfunction. Ischaemic oedema is initially cytotoxic, with a shift of Na+ and CI- ions from ECS to ICS, followed by osmotically obliged water, this shift can be detected by diffusion-weighted MRI. Later in the evolution of an ischaemic lesion the oedema becomes vasogenic, with disruption of the BBB. Recent imaging studies in patients with head injury suggest that the development of traumatic brain oedema may follow a biphasic time course similar to that of ischaemic oedema. Hydrocephalus is associated in the great majority of cases with an obstruction to the circulation or drainage of CSF, or, occasionally, with overproduction of CSF by a choroid plexus papilloma. In either case, the consequence is a ris
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PMID:The normal and pathological physiology of brain water. 907 71

We have successfully cultured choroid plexus epithelial cells from porcine brain in pure form by the addition of cytosine arabinoside to the culture medium which prevented growth of other contaminating cells. We characterized the cells in culture by the presence of desmoplakin, fibronectin, thrombospondin, and the zonula occludens protein ZO-1 in comparison to frozen fractions of the isolated choroid plexus tissue. The cells in culture express those marker proteins and moreover exhibit a polarized phenotype which was expected from the presence of tight junction strands that correlate to an electrical resistance of 120 Ohm.cm2 measured across the cell monolayer on a permeable support. Permeability studies with fluorescein-labeled dextrans also indicate a biochemical tightness. The polarity of the cells is demonstrated by the presence of microvilli and cilia on the surface of the cultured cells as well as by the laser scanning microscopic determination of the apical localization of the ZO-1-protein and the Na+K(+)-ATPase. Thrombospondin and fibronectin were found to be localized at the basolateral membrane side. The cells in culture secrete medium containing prealbumin predominantly into the apical compartment which demonstrates that they are able to release medium containing CSF-proteins and therefore verifies the usefulness of this in vitro model.
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PMID:Porcine choroid plexus cells in culture: expression of polarized phenotype, maintenance of barrier properties and apical secretion of CSF-components. 930 92

The Cl-/HCO3- exchanger (AE2 isoform) and the Na+/K(+)-ATPase at the choroid plexus are both thought to be involved in CSF secretion. However, both transport mechanisms are also postulated to have a role in CSF ion homeostasis raising questions as to which parameters control the expression of these transporters? Northern blots have been used to assess AE2 mRNA levels in rats subjected to alterations in blood pH or blood osmolality (a factor affecting CSF secretion). Six hours of alkalosis induced a 40% increase in AE2 mRNA (p < 0.01), suggesting that alterations in the expression of this transporter play a role in CSF pH homeostasis. In contrast, changes in osmolality did not affect AE2 mRNA. Western blots of Na+/K(+)-ATPase subunits were also examined to determine whether hypo and hyperkalemia affect protein levels of this transporter. There was a positive correlation between the plasma K+ concentration and both alpha 1- and beta 1 subunit protein levels suggesting a role for this transporter in CSF K+ homeostasis. As changes in plasma K+ and pH affect choroid plexus ion transporters but do not appear to alter CSF production, these results suggest the presence of compensatory mechanisms. Understanding of such mechanisms may facilitate therapeutic control of CSF production.
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PMID:Choroid plexus ion transporter expression and cerebrospinal fluid secretion. 941 46

This study was done to elucidate the mechanism of hypoglycorrhachia and elevated lactate concentrations leading to neuronal dysfunction in neonatal meningitis, and to determine the effects of induced hyperglycemia on these disturbances. Thirty-eight newborn piglets were divided into three groups: 12 in the control group (CG), 12 in the normoglycemic meningitis group (NG), and 14 in the hyperglycemic meningitis group (HG). Meningitis was induced by intracisternal injection of 108 cfu of Escherichia coli. Hyperglycemia (blood glucose 300-400 mg dl-1) was induced and maintained for 60 min before induction of meningitis and throughout the experiment using modified glucose clamp technique. CSF-to-blood glucose ratio decreased significantly in NG. In HG, baseline CSF-to-blood glucose ratio was lower than two other groups, but increased at 1 h after induction of meningitis. CSF lactate concentration was increased progressively in both meningitis groups, and positively correlated with CSF leukocyte numbers (r=0.41, p<0.001) and TNF-alpha level (r=0.43, p<0.001). Brain glucose concentration was significantly increased in HG and showed inverse correlation with CSF leukocyte numbers (r=-0.59, p<0.01). Brain lactate concentration was not significantly different among three groups and positively correlated with the CSF TNF-alpha level (r=0.51, p<0.05). Lipid peroxidation products were increased in NG. Na+,K+-ATPase activity, ATP/PCr concentrations were not different among three groups. Increased intracranial pressure, CSF pleocytosis (214+/-59 vs. 437+/-214/mm3, p<0.02) and increased lipid peroxidation products observed in NG were reduced in HG. These results suggest that hypoglycorrhachia and elevated lactate concentration in the CSF during meningitis originates primarily from the increased anaerobic glycolysis in the subarachnoid space, induced by TNF-alpha and leukocytes. Induced hyperglycemia attenuates the inflammatory responses of meningitis and might be beneficial by providing an increased glucose delivery to meet its increased demand in meningitis.
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PMID:Effect of induced hyperglycemia on brain cell membrane function and energy metabolism during the early phase of experimental meningitis in newborn piglets. 966 26

The purpose of this study was to test the hypothesis that hyperglycemia ameliorates changes in brain cell membrane function and preserves cerebral high energy phosphates during hypoxia-ischemia in newborn piglets. A total of 42 ventilated piglets were divided into 4 groups, normoglycemic/normoxic(group 1, n=9), hyperglycemic/normoxic(group 2, n=8), normoglycemic/hypoxic-ischemic(group 3, n=13) and hyperglycemic/hypoxic-ischemic(group 4, n=12) group. Cerebral hypoxia-ischemia was induced by occlusion of bilateral common carotid arteries and simultaneous breathing with 8% oxygen for 30 min. Hyperglycemia (blood glucose 350-400 mg/dl) was maintained for 90 min before and throughout hypoxia-ischemia using modified glucose clamp technique. Changes in cytochrome aa3 were continuously monitored using near infrared spectroscopy. Blood and CSF glucose and lactate were monitored. Na+, K+-ATPase activity, lipid peroxidation products (conjugated dienes), tissue high energy phosphates (ATP and phosphocreatine) levels and brain glucose and lactate levels were determined biochemically in the cerebral cortex. During hypoxia-ischemia, glucose levels in blood and CSF were significantly elevated in hyperglycemic/hypoxic-ischemic group compared with normoglycemic/hypoxic-ischemic group, but lactate levels in blood and CSF were not different between two groups. At the end of hypoxia-ischemia of group 3 and 4, triangle up Cyt aa3, Na+, K+-ATPase activity, ATP and phosphocreatine values in brain were significantly decreased compared with normoxic groups 1 and 2, but were not different between groups 3 and 4. Levels of conjugated dienes and brain lactate were significantly increased in groups 3 and 4 compared with groups 1 and 2, and were significantly elevated in group 4 than in group 3 (0.30+/-0.11 vs. 0.09+/-0.02 micromol g-1 protein, 26.4+/-7.6 vs. 13.1+/-2.6 mmol kg-1, p<0.05). These findings suggest that hyperglycemia does not reduce the changes in brain cell membrane function and does not preserve cerebral high energy phosphates during hypoxia-ischemia in newborn piglets. We speculate that hyperglycemia may be harmful during hypoxia-ischemia due to increased levels of lipid peroxidation in newborn piglet.
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PMID:Effect of hyperglycemia on brain cell membrane function and energy metabolism during hypoxia-ischemia in newborn piglets. 966 46

Case 1: A 27-year-old man had a fever of 38 degrees C, followed by acute onset of bilateral upper arm pain. Two days later severe muscle weakness in bilateral upper arms appeared and he was admitted to our hospital. On admission, severe atrophy of the left deltoid and mild atrophy of the right deltoid were observed, with severe muscle weakness in bilateral deltoid and mild weakness in other parts of upper extremities. Tendon reflexes were decreased in the upper extremities. Sensation was intact. CSF showed mild pleocytosis. Nerve conduction velocity was normal and electromyography showed mild NMU decrease in upper extremities. Muscle biopsy of the right deltoid one month after the onset was normal. Muscle weakness began to improve 3 months after the onset, with only mild weakness at 10 months. Case 2: A 60-year-old man had acute onset of left shoulder and upper arm pain, followed by muscle atrophy and weakness of the left upper arm. He showed marked atrophy of the left deltoid, moderate atrophy of the left biceps and left scapular region, and severe muscle weakness in the left upper arm. Deep tendon reflexes were absent in the left upper extremity. Sensation was intact. Nerve conduction velocity was normal and electromyography showed marked NMU decrease in the left upper arm. Muscle biopsy of the left biceps 4 months after the onset showed grouped atrophies on HE staining, type 2 fiber atrophies on routine ATPase staining, and many targetoid atrophic fibers on NADH-TR staining. Muscle weakness began to improve slowly 6 months after the onset, but considerable weakness persisted at 10 months. Detailed muscle biopsy findings in neuralgic amyotrophy have not been documented. Muscle biopsy of Case 2 showed marked neurogenic changes compared to Case 1, which may be associated with the difference in clinical course between the two cases.
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PMID:[Two cases of neuralgic amyotrophy]. 986 14

This study examined the potential roles of the plasma membrane Ca2+-ATPase (PMCA) at the blood-CSF and blood-brain barriers in brain Ca2+ homeostasis and blood-brain barrier Na+/K+-ATPase subunits in brain K+ homeostasis. During dietary-induced hypo- and hypercalcemia (0.59+/-0.06 and 1.58+/-0.12 mM [Ca2+]) there was no significant change in choroid plexus PMCA (Western Blots) compared to normocalcemic rats (plasma [Ca2+]: 1.06+/-0.11 mM). In contrast, PMCA in cerebral microvessels isolated from hypocalcemic rats was 150% greater than that in controls (p<0.001). Comparison of the alpha3 subunit of Na+/K+-ATPase from cerebral microvessels isolated from hypo-, normo- and hyperkalemic rats (2.3+/-0.1, 3.9+/-0.1 and 7. 2+/-0.6 mM [K+]) showed a 75% reduction in the amount of this isoform during hyperkalemia. None of the other Na+/K+-ATPase isoforms varied with plasma [K+]. These results suggest that both PMCA and the alpha3 subunit of Na+/K+-ATPase at the blood-brain barrier play a role in maintaining a constant brain microenvironment during fluctuations in plasma composition.
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PMID:Blood-brain barrier mechanisms involved in brain calcium and potassium homeostasis. 987 35

This study was done to evaluate the efficacy of anti-tumor necrosis factor alpha (anti-TNF-alpha) antibody as an adjunctive therapy in neonatal bacterial meningitis. Newborn piglets were divided into three groups: 8 in the control group, 13 in the meningitis group (MG), and 10 in the meningitis with anti-TNF-alpha antibody group (AG). Meningitis was induced by intracisternal injection of 10(8) colony-forming units of Escherichia coli in 100 microl of saline. In the AG, 200 microl of anti-TNF-alpha antibody was also given intracisternally. In the AG, the elevated cerebrospinal fluid TNF-alpha level observed in the MG was completely abolished, and increased intracranial pressure, hypoglycorrhachia, and CSF pleocytosis observed in the MG were downmodulated. But blood, brain, and CSF lactate levels remained elevated in both MG and AG. Increased brain cell membrane lipid peroxidation products and decreased Na+,K+-ATPase activity observed in the MG were not attenuated in the AG. These results indicate that anti-TNF-alpha antibody was not particularly effective as an adjunctive therapy in attenuating acute inflammatory responses and ameliorating brain damage in neonatal bacterial meningitis.
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PMID:Efficacy of anti-tumor necrosis factor-alpha antibody as an adjunctive therapy in experimental Escherichia coli meningitis in the newborn piglet. 1032 41

Hyperargininemia is a metabolic disorder biochemically characterized by tissue accumulation of arginine (Arg) and other guanidino compounds (GC). Convulsions, lethargy and psychomotor delay are predominant clinical features of this disease. Considering that some GC are epileptogenic and cause a decrease in membrane fluidity and that Na+,K(+)-ATPase, a membrane-bound enzyme, is essential for cellular excitability and is decreased in experimental and human epilepsy, in the present study we determined the in vitro effects of Arg, N-acetylarginine (NAA), argininic acid (AA) and homoarginine (HA) on the activity of Na+,K(+)-ATPase in the synaptic plasma membrane from cerebral cortex of young rats in the hope to identify a possible mechanism for the brain damage in hyperargininemia. The results showed that all GC tested, except Arg, significantly inhibited Na+,K(+)-ATPase activity at concentrations similar to those observed in plasma and CSF of patients with hyperargininemia. In addition, competition between NAA, AA and HA for the binding to the enzyme was observed, suggesting a common binding site for the GC. It is therefore possible that the inhibitory effect of GC on Na+,K(+)-ATPase may be related to the brain dysfunction observed in hyperargininemia.
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PMID:In vitro inhibition of Na+,K(+)-ATPase activity from rat cerebral cortex by guanidino compounds accumulating in hyperargininemia. 1044 19


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