Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activation volumes (delta V++) have been determined for several reactions of peroxynitrite using the stopped-flow technique. Spontaneous decomposition of ONOOH to NO3- in 0.15 M phosphate, pH 4.5, gave delta V++ = 6.0 +/- 0.7 and 14 +/- 1.0 cm3 mol-1 in the presence of 53 microM and 5 mM nitrite ion, respectively. One-electron oxidations of Mo(CN)8(4-) and Fe(CN)6(4-), which are first order in peroxynitrite and zero order in metal complex, gave delta V++ = 10 +/- 1 and 11 +/- 1 cm3 mol-1, respectively, at pH 7.2. The limiting yields of oxidized metal complex were found to decrease from 61 to 30% of the initially added peroxynitrite for Mo(CN)8(3-) and from 78 to 47% for Fe(CN)6(3-) when the pressure was increased from 0.1 to 140 MPa. The bimolecular reaction between CO2 and ONOO- was determined by monitoring the oxidation of Fe(CN)6(4-) by peroxynitrite in bicarbonate-containing 0.15 M phosphate, pH 7.2, for which delta V++ = -22 +/- 4 cm3 mol-1. The Fe(CN)6(3-) yield decreased by approximately 20% upon increasing the pressure from atmospheric to 80 MPa. Oxidation of Ni(cyclam)2+ by peroxynitrite, which is first order in each reactant, was characterized by delta V++ = -7.1 +/- 2 cm3 mol-1, and the thermal activation parameters delta H++ = 4.2 +/- 0.1 kcal mol-1 and delta S++ = -24 +/- 1 cal mol-1 K-1 in 0.15 M phosphate, pH 7.2. These results are discussed within the context of the radical cage hypothesis for peroxynitrite reactivity.
 ...
PMID:Pressure dependence of peroxynitrite reactions. Support for a radical mechanism. 1120 11

The pattern of side-chain conservation at the cytoplasmic side of the third transmembrane domain of rhodopsin family G protein-coupled receptors, Asp/Glu-Arg-Tyr/X-X-X-Ile/Val, defines a structural "arginine cage" domain. Previous computational and mutagenesis studies of the GnRH receptor indicated an important contribution of local interactions to the function of this domain. We have investigated the functional importance of the intrahelical position and orientation of the arginine cage using insertional mutagenesis. Introduction of a single Ala proximal to the conserved Asp-Arg of this domain caused loss of detectable ligand binding. Inserting a second Ala, however, restored high-affinity agonist binding. Further insertion of three or four Ala residues at this site generated receptors that bound agonist with an affinity 3- to 10-fold higher than that of the wild-type receptor. Loss of detectable coupling to inositol phosphate turnover in all these mutant receptors confirms that the structure required in this region for efficient signaling is highly constrained. In contrast, the recovery of agonist binding with the progressive insertion of two to four Ala residues indicates that specific orientations of this segment can stabilize high-affinity receptor conformations that are uncoupled from signal transduction.
 ...
PMID:Insertional mutagenesis of the arginine cage domain of the gonadotropin-releasing hormone receptor. 1122 40

A number of novel phosphate binders based on mixed metal hydroxide structures incorporating Fe and Ca, or Fe and Mg (classified as CT, Crosfield test compounds), were compared with the established phosphate binders Mg(OH)2, Al(OH)3, CaCO3 and a commercial hydrotalcite (Al- and Mg-based) using a rat model. The changes in urine and soluble faecal phosphate were used to evaluate efficacy of phosphate binding. The binders were mixed into a standard rat maintenance food at a concentration of 1% (w/w). Four rats were used for each binder study group and fed over 7 days. Urine and faeces were collected (in a metabolic cage) over the last 24-h study period and the phosphate content measured. The urinary phosphate was significantly reduced (P < 0.001) with CTFeCa (72+/-44 microm), CTFeMg (13+/-4 microm), CT100 (26+/-11 microm), and Mg(OH)2 (65+/-53 microm), compared with control (766+/-188 microm), Al(OH)3 (1,256+/-279 microm), and CaCO3 (857+/-25 microm). The soluble phosphate content of the faeces was significantly reduced (P < 0.05) by up to 60 % with CTFeCa, CTFeMg and Mg(OH)2, and up to 40% with CT100 and Al(OH)3, compared with 30% in controls and 10% with CaCO3. The new mixed metal hydroxy-carbonate compounds based on FeCa or FeMg are effective phosphate binders in-vivo and warrant further testing in patients.
 ...
PMID:The evaluation of novel mixed metal hydroxy-carbonates as phosphate binders: an in-vivo study in the rat. 1134 68

1. Trimethylolpropane phosphate (TMPP) is a potent cage convulsant, reported to act through binding to the picrotoxinin and/or benzodiazepine receptor sites of the gamma-aminobutyricA (GABA(A)) ionophore complex. 2. Adult male Fischer-344 rats were pretreated by intraperitoneal (i.p.) injection with either diazepam (DZP) [0.5-5.0 mg/kg], Phenobarbital (PB) [5-20 mg/kg], dizocilpine maleate (MK-801) [0.5-3.0 mg/kg], Tiagabine (TGB) [0.5-5.0 mg/kg], 6,7-dinitro-quinoxaline-2,3-dione (DNQX), [5-20 mg/kg], or scopolamine [SCP] (0.25-1.0 mg/kg) 30 min prior to i.p. injection with a convulsive dose of TMPP (0.6 mg/kg). 3. Rats were rated for occurrence of convulsive activity for 120 min post-injection. Time from TMPP injection to observation of subclinical seizures, generalized (tonic-clonic) seizures, and lethality was rated for each pretreatment group. 4. In general, DZP = PB > TGB in reduction of TMPP subclinical and/or clinical seizures. MK-801, at dose levels inducing near sedation, was also effective in modulation of TMPP-induced seizures. SCP or DNQX were generally ineffective in reducing or eliminating TMPP-induced seizures.
 ...
PMID:Reduction of motor seizures in rats induced by the ethyl bicyclophosphate trimethylolpropane phosphate (TMPP). 1147 48

The interaction of Cu(II) with the ligand tdci (1,3,5-trideoxy-1,3,5-tris(dimethylamino)-cis-inositol) was studied both in the solid state and in solution. The complexes that were formed were also tested for phosphoesterase activity. The pentanuclear complex [Cu(5)(tdciH(-2))(tdci)(2)(OH)(2)(NO(3))(2)](NO(3))(4).6H(2)O consists of two dinuclear units and one trinuclear unit, having two shared copper(II) ions. The metal centers within the pentanuclear structure have three distinct coordination environments. All five copper(II) ions are linked by hydroxo/alkoxo bridges forming a Cu(5)O(6) cage. The Cu-Cu separations of the bridged centers are between 2.916 and 3.782 A, while those of the nonbridged metal ions are 5.455-5.712 A. The solution equilibria in the Cu(II)-tdci system proved to be extremely complicated. Depending on the pH and metal-to-ligand ratio, several differently deprotonated mono-, di-, and trinuclear complexes are formed. Their presence in solution was supported by mass, CW, and pulse EPR spectroscopic study, too. In these complexes, the metal ions are presumed to occupy tridentate [O(ax),N(eq),O(ax)] coordination sites and the O-donors of tdci may serve as bridging units between two metal ions. Additionally, deprotonation of the metal-bound water molecules may occur. The dinuclear Cu(2)LH(-3) species, formed around pH 8.5, provides outstanding rate acceleration for the hydrolysis of the activated phosphodiester bis(4-nitrophenyl)phosphate (BNPP). The second-order rate constant of BNPP hydrolysis promoted by the dinuclear complex (T = 298 K) is 0.95 M(-1) s(-1), which is ca. 47600-fold higher than that of the hydroxide ion catalyzed hydrolysis (k(OH)). Its activity is selective for the phosphodiester, and the hydrolysis was proved to be catalytic. The proposed bifunctional mechanism of the hydrolysis includes double Lewis acid activation and intramolecular nucleophilic catalysis.
 ...
PMID:Highly efficient phosphodiester hydrolysis promoted by a dinuclear copper(II) complex. 1153 40

Responses of high-energy phosphates and metabolic properties to hindlimb suspension were studied in adult rats. The relative content of phosphocreatine (PCr) in the calf muscles was significantly higher in rats suspended for 10 days than in age-matched cage controls. The Pi/PCr ratio, where Pi is inorganic phosphate, in suspended muscles was less than controls. The absolute weights of soleus and medial gastrocnemius (MG) were approximately 40% less than controls. Although the % fiber distribution in MG was unchanged, the % slow fibers decreased and the % fibers which were classified as both slow and fast was increased in soleus. The activities (per unit weight or protein) of succinate dehydrogenase and lactate dehydrogenase in soleus were unchanged but those of cytochrome oxidase, beta-hydroxyacyl CoA dehydrogenase, and citrate synthase were decreased following unloading. None of these enzyme activities in MG changed. However, the total levels of all enzymes in whole muscles decreased by suspension. It is suggested that shift of slow muscle toward fast type by unloading is associated with a decrease in mitochondrial biogenesis. Further, gravitational unloading affected the levels of muscle proteins differently even in the same mitochondrial enzymes.
 ...
PMID:Metabolic adaptation of skeletal muscles to gravitational unloading. 1153 10

Exposure to microgravity causes alterations in postural, locomotor and oculomotor functions. The vestibular abnormalities experienced by astronauts entail immediate reflex motor responses, including postural illusions, sensations of rotation, nystagmus, dizziness and vertigo, as well as space motion sickness. Adaptation to the microgravity environment usually occurs within one week, and a subsequent re-adaptation period of several months is often required upon return to Earth. Some astronauts experience recurrences of dizziness, nausea, and vomiting, as well as marked disturbances in postural equilibrium in the absence of vision during this readaptation period. The mechanisms underlying such adaptation processes remain unclear, although current evidence favors some type of sensory conflict. The purpose of the present study was to explore the structural basis for the reorganization in the central vestibular system that underlies the process of adaptation to altered gravitational environments. Hindbrain tissue was obtained from rats flown on the Neurolab shuttle mission (STS-90) that launched on April 17, 1998. Tissue for the present report was obtained from four adult Fisher 344 rats sacrificed on orbit during flight day 2 (FD2), 24 hr after launch. Equal numbers of vivarium control animals and cage-controls were sacrificed 48 and 96 hr, respectively, after the flight dissections. Following decapitation, each hindbrain was immersion-fixed for 45 min in 4% paraformaldehyde/0.1% glutaraldehyde in 0.1M phosphate buffer pH 7.3, and then transferred to a 4% paraformaldehyde solution in 0.1M phosphate buffer for 18 days at 4 degrees C. After this fixation, the cerebellum was dissected away from the ventral portion of the brainstem by severing the cerebellar peduncles. The entire cerebellum of each rat was cut by Vibratome into 100 micrometers thick sections in the parasagittal plane. These sections were collected serially and processed for electron microscopy by osmication, dehydration in a graded series of methanol solutions, infiltration with resin, and embedment in Epon-Araldite resin between plastic coverslips.
 ...
PMID:Anatomical observations of the rat cerebellar nodulus after 24 hr of spaceflight. 1154 23

When dissolved in N,N-dimethylformamide and then dialyzed against phosphate-buffered saline, A-B-A block copolymers composed of poly [N5-(2-hydroxyethyl)-L-glutamine]-block-poly(gamma-benzyl-L-glutamate)- block-poly [N5-(2-hydroxyethyl)-L-glutamine] form particles. The particles are cage-like structures with average diameters of 300 nm (average polydispersity, 0.3-0.5). They are stable in aqueous solution at 4 degrees C for up to 3 weeks, at which time flocculation becomes apparent. Negative staining and freeze-fracture electron microscopy suggest that cage-like particles are formed by selective association of segregated micelle populations. A model of particle formation is presented in which B blocks form micelles in dimethylformamide. On dialysis against an aqueous solution, the extended A blocks then associate intermolecularly to form rod-shaped micelles, which connect the B block micelles. The result is a meshed cage-like particle. The implications of these observations on the aggregation behavior of polymeric surfactants in dilute solution are discussed.
 ...
PMID:Formation of cage-like particles by poly(amino acid)-based block copolymers in aqueous solution. 1160 45

Three hundred, day-old broiler chicks, with an average initial weight of 41.8 +/- 1.79 g, were used in a 15-day study (10 birds per battery cage) to characterize their performance and fluorine status when dicalcium phosphate (DCP) was replaced by Busumbu rock phosphate (BRP) as the source of phosphorus in the chicks' ration. The treatments comprised a standard ration with BRP replacing 0, 25%, 50%, 75% or 100% of DCP. Replacing DCP with BRP significantly reduced the final weight of the chicks (p < 0.01), feed intake (p < 0.01), weight gains (p < 0.01) and dry matter digestibility (p < 0.05) but increased (p < 0.05) the feed-to-gain ratio. True phosphorus absorption and the percentage of phosphorus in the tibia were not affected by increasing amounts of BRP in the diet. Increasing levels of BRP in the diet linearly reduced (p < 0.01) the percentage bone ash, calcium, Ca:P ratio, ultimate breaking force, bending moment, stress, and modulus of elasticity. Leg stiffness, lameness, reduced feed intake, and a decline in general health were recorded in 10-40% of the chicks on 75% and 100% BRP, respectively. These results suggest that excessive ingestion of fluorine from the BRP caused the reduction in the chicks' performance.
 ...
PMID:The effects of replacing dicalcium phosphate with Busumbu rock phosphate on performance and the mechanical properties of bone in growing chicks. 1216 36

Adult male Long-Evans rats were subjected to bilateral lesions of the cholinergic neurons in the nucleus basalis magnocellularis (NBM) by injection of 0.2 or 0.4 microg 192-IgG-saporin in 0.4 microl phosphate-buffered saline. Control rats received an equivalent amount of phosphate-buffered saline. Starting 2 weeks after surgery, all rats were tested for locomotor activity in their home cage, beam-walking performance, T-maze alternation rates (working memory), reference and working memory performance in a water-maze task, and memory capabilities in the eight-arm radial maze task using uninterrupted and interrupted (delay of 2 min, 2 h and 6 h after four arms had been visited) testing procedures. Histochemical analysis showed a significant decrease of acetylcholinesterase (AChE)-positive reaction products (30-66%) in various cortical regions at the 0.2-microg dose. At the dose of 0.4 microg, there was an additional, although weak, damage to the hippocampus (17-30%) and the cingulate cortex (34%). The behavioral results showed only minor impairments in spatial memory tasks, and only during initial phases of the tests (reference memory in the water maze, working memory in the radial maze). The behavioral effects of the dramatic cholinergic lesions do not support the idea of a substantial implication of cholinergic projections from the NBM to the cortex in the memory processes assessed in this study, but they remain congruent with an involvement of these projections in attentional functions.
 ...
PMID:Selective immunolesions of CH4 cholinergic neurons do not disrupt spatial memory in rats. 1217 91


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