Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pig coronary artery cultured smooth muscle cells were skinned using saponin. In the presence of an ATP-regenerating system and oxalate, the skinned cells showed an ATP-dependent azide insensitive Ca(2+)-uptake which increased linearly with time for > 1 h. The Ca(2+)-uptake occurred with Km values of 0.20 +/- 0.03 microM for Ca2+ and 400 +/- 34 microM for MgATP2-. Thapsigargin and cyclopiazonic acid inhibited this uptake with IC50 values of 0.13 +/- 0.02 and 0.56 +/- 0.04 microM, respectively. These properties of SR Ca(2+)-pump are similar to those reported for membrane fractions isolated from fresh smooth muscle of coronary artery and other arteries. However, optimum pH of the uptake in the skinned cells (6.2) was lower than that reported previously using isolated membranes (6.4-6.8).
Mol Cell Biochem 1995 Oct 18
PMID:Properties of the sarcoplasmic reticulum Ca(2+)-pump in coronary artery skinned smooth muscle. 856 60

Calcium oxalate crystal growth and aggregation leads to the formation of renal calculi. It is known to be inhibited by several compounds both in vitro and in vivo conditions. The present study highlights the inhibitory potential of sodium pentosan polysulphate (SPP), a semi-synthetic glycosaminoglycan (GAG) on calcium oxalate crystal growth in vitro. Its efficacy was compared with those of known inhibitors like pyrophosphate, heparin and chondroitin-4-sulphate. Of the above compounds pyrophosphate was found to be the most potent inhibitor. Among the GAGs, SPP exhibited 80% inhibitory activity as compared to heparin. A lesser degree of inhibition was observed with chondroitin-4-sulphate.
Mol Cell Biochem 1996 Mar 09
PMID:Influence of sodium pentosan polysulphate and certain inhibitors on calcium oxalate crystal growth. 870 73

Previous studies on the role of trace elements (TE) in the development of calcium oxalate (CaOx) human kidney stones by nuclear microprobe (NMP) investigated the mechanisms and role of TE in the buildup of urinary CaOx concretions. In the present work, microanalysis of the previously reported series of recurrent human kidney stones was further expanded. Interest was focused on determining levels of directional variability in elemental concentrations of Ca and TE throughout selected micro-regions of single stones by Dynamic Analysis (DA).
Cell Mol Biol (Noisy-le-grand) 1996 Feb
PMID:Microanalysis of calcium-rich human kidney stones at the NAC nuclear microprobe. 883 73

We evaluated the effect of ischemia and reperfusion on sarcoplasmic reticulum Ca uptake in patients subjected to cardiac surgery. Our series included 16 patients (seven female, nine male, age 63 +/- 2 years): five were subjected to aortic valve replacement, five to aortic and mitral valve replacement, six to coronary artery bypass graft. In each case no clinical, electrocardiographic or echocardiographic evidence of perioperative infarction was observed. Biopsies were obtained from the right atrium of each patient before starting extracorporeal circulation, and after the recovery of spontaneous contractile activity, i.e. after cardioplegia-ischemia-reperfusion. The tissue was homogenized, and oxalate-supported Ca uptake, which represents sarcoplasmic reticulum Ca uptake, was measured in the unfractionated homogenate. The assay was performed under basal conditions and in the presence of 900 microM ryanodine, in order to block sarcoplasmic reticulum Ca release channels. Under basal conditions at pCa = 5.85 the rate of sarcoplasmic reticulum Ca uptake averaged 4.76 +/- 0.37 nmol/min per mg of protein in the pre-ischemic samples, and decreased significantly in the post-ischemic samples (3.09 +/- 0.29 nmol/min per mg, P < 0.01). A significant decrease of Ca uptake after ischemia and reperfusion was observed also in the presence of ryanodine (3.53 +/- 0.48 nmol/min per mg) compared to pre-ischemic values (5.98 +/- 0.56 nmol/min per mg, P < 0.01). Additional experiments showed no change in the Ca sensitivity of Ca uptake in the postischemic samples (Kca = 0.48 +/- 0.02 microM, no significant difference after ischemia and reperfusion). In conclusion, active sarcoplasmic reticulum Ca transport was impaired in human atrial myocardium after reversible ischemia and reperfusion.
J Mol Cell Cardiol 1996 Aug
PMID:Sarcoplasmic reticulum calcium uptake in human myocardium subjected to ischemia and reperfusion during cardiac surgery. 887 79

Heat stress (HS) and the subsequent expression of heat shock proteins has been shown to enhance post-ischemic functional recovery and reduce infarct size. The purpose of these experiments was to determine if HS pre-treatment preserves sarcoplasmic reticulum (SR) function, a cellular organelle that plays an important role in myocardial contractility. Anesthetized rats were heat stressed for 15 min by raising temperature to 42 degrees C. Twenty-four hours later the hearts were perfused by Langendorff's method and subjected to either 20 or 35 min of global ischemia, with a subset of hearts then being subjected to 10 or 20 min of reperfusion, respectively. SR function was assessed by oxalate-supported Ca2+ uptake rate in cell free preparations in the presence and absence of ruthenium red, a selective SR calcium release channel blocker Ca2+ uptake decreased significantly from 25.6 +/- 3.4 to 13.4 +/- 1.9 and 11.3 +/- 2.3 nmol/min/mg protein (mean +/- S.E.), following 20 and 35 min of ischemia, respectively. A similar trend was observed following reperfusion as well. No significant difference in Ca2+ uptake was observed between HS v control hearts. Similarly, in samples where the Ca2+ release channel was blocked with ruthenium red, decreased Ca2+ uptake rates were noted after both ischemia and reperfusion, with no significant differences seen between HS and non-HS hearts. There was significant improvement it developed pressure. +dP/dt and -dP/dt, with reduced creatine kinase release in HS v non-HS hearts. Western blot analysis demonstrated increased synthesis of 27- and 70-kDa heat shock proteins in HS but not in control animals. It is concluded that HS improves functional recovery and induces expression of 27- and 70-kDa heat shock proteins without preservation of SR function in the globally ischemic rat heart.
J Mol Cell Cardiol 1996 Sep
PMID:Heat stress improves functional recovery and induces synthesis of 27- and 70-kDa heat shock proteins without preserving sarcoplasmic reticulum function in the ischemic rat heart. 889 47

This comparative study investigates the relationship between sarcoplasmic reticulum (SR) calcium(Ca2+)-ATPase transport activity and phospholamban (PLB) phosphorylation in whole cardiac homogenates of spontaneously hypertensive rats (SHR) and their parent, normotensive Wistar Kyoto (WKY) strain during early postnatal development at days 1, 3, 6, 12 and at day 40 to ascertain any difference in SR Ca2+ handling before the onset of hypertension. At day 1, the rate of homogenate oxalate-supported Ca2+ uptake was significantly higher in SHR than in WKY (0.25 +/- 0.02 vs 0.12 +/- 0.01 nmoles Ca2+/mg wet ventricular weight/min, respectively; p < 0.001). This interstrain difference disappeared with further developmental increase in SR Ca2+ transport. Western Blot analysis and a semiquantitative ELISA did not reveal any difference in the amount of immunoreactive PLB (per mg of total tissue protein) between strains at any of the ages studied. In addition, levels of phosphorylated PLB formed in vitro in the presence of radiolabelled ATP and catalytic (C) subunit of protein kinase A did not differ between SHR and WKY at days 1, 3, 6 and 12. At day 40, C subunit-catalyzed formation of 32P-PLB was reduced by 66% (p < 0.001) in SHR when compared to age-matched WKY. In the early postnatal period between day 1 and 12 SR Ca(2+)-transport values were linearly related to the respective 32P-PLB levels of both SHR and WKY rats. The results indicate that cardiac SR of SHR can sequester Ca2+ at a much higher rate immediately after birth compared to WKY rats. The disappearance of this interstrain difference with further development suggests that some endogenous neuroendocrine or nutritional factor(s) from the hypertensive mother may exert an influence upon the developing heart in utero resulting in a transiently advanced maturation of the SR Ca2+ transport function in SHR pups at the time of birth.
Mol Cell Biochem
PMID:Early postnatal changes in sarcoplasmic reticulum calcium transport function in spontaneously hypertensive rats. 897 40

The rat liver nuclear oxalate binding protein was isolated, purified by anion and cation exchange column chromatography using Diethyl Amino Ethyl Sephadex, Carboxy Methyl Cellulose and Carboxy Methyl Sephadex C-50 ion exchangers. The purified oxalate binding protein was found to be H1B of H1 fraction of histones. Kinetic analysis of oxalate binding showed the presence of two affinity sites, one with Kd of 133.5 nM and Bmax of 40 pmoles and another with Kd of 262.5 nM and Bmax of 210 pmoles. The optimal oxalate binding was at pH 4.2 and at 28 degrees C. The oxalate binding was specific and reversible and not due to ionic charge interaction. The IC50 of other dicarboxylates was higher than that of oxalate. EGTA had no effect on oxalate binding but di- and tri-carboxylate carrier inhibitors and thiol modifying agents significantly lowered the binding activity. Oxalate binding to histones was significantly reduced in the presence of DNA or nucleotides, but RNA had no effect. ATP completely inhibited the oxalate binding activity at 1 mM concentration. Different tissues exhibited oxalate binding showing ubiquitous nature. Calf thymus H1 showed maximal binding similar to liver histones.
Mol Cell Biochem 1996 Mar 23
PMID:Occurrence of histone-related oxalate binding in rat liver nucleus. 909 64

The effect of 15 min of global, normothermic ischemia on cardiac sarcoplasmic reticulum (SR) was investigated using the Ca2+ uptake rate and 3H-ryanodine binding of ventricular homogenates and isolated SR vesicles. Ischemia did not affect ryanodine binding in the homogenate, while it increased it in the isolated SR vesicles. Although ischemia decreased the homogenate oxalate-supported Ca2+ uptake rate, measured in the presence of high ryanodine to close the ryanodine-sensitive efflux pathway (+RY), its decrease of the Ca2+ uptake rate, measured in the absence of ryanodine (-RY), was more marked. This finding was also observed in the isolated SR. Although inhibition of the Ca-ATPase and its coupled Ca2+ uptake by thapsigargin proportionately decreased SR Ca2+ uptake -RY and +RY, ischemia decreased the Ca2+ uptake -RY proportionately more. This result suggested that there was a greater fraction of Ca2+ uptake activity in ryanodine-sensitive vesicles after ischemia. However, ischemia also reduced the yield of SR activity in the isolated SR fraction and the results could potentially be due to differential selection of ryanodine-sensitive and ryanodine-insensitive SR in the isolation procedure. We directly tested the hypothesis that ischemia changes the fraction of Ca2+ uptake activity in the ryanodine-sensitive vesicles by estimating the Ca-oxalate capacity measured +RY and -RY. Ischemia decreased the capacity -RY much more than +RY in the homogenate, indicating that more of the SR volume and Ca2+ uptake activity was in the ryanodine-sensitive vesicles after ischemia.
J Mol Cell Cardiol 1997 May
PMID:Effect of ischemia on the fraction of ryanodine-sensitive cardiac sarcoplasmic reticulum. 920 22

Wheat germin is a protein expressed during germination which possesses an oxalate oxidase activity. Germin-type oxalate oxidases have been extensively studied in monocotyledons (wheat and barley) where they are thought to have important functions for development, stress response and defence against pathogens. In contrast, almost nothing is known about the germin-like proteins found in dicotyledons, gymnosperms and myxomycetes. In this work, cDNA clones for three genes (ATGER1, ATGER2 and ATGER3) encoding germin-like proteins, initially characterized as expressed sequence tags (ESTs), from Arabidopsis thaliana cDNA libraries were further characterized. In addition, we isolated and sequenced a Brassica napus cDNA which was strongly homologous to the cDNA for ATGER1. Sequence analysis and secondary structure predictions of the proteins encoded by these cDNAs showed that they possess all the characteristic features of members of the germin family and of the germin/seed globulins/sucrose binding protein superfamily. Sequence comparisons and mapping demonstrated the existence of at least two different gene families in the A. thaliana genome encoding a minimum of three genes for germins. These three genes have been mapped in three different location on the Arabidopsis genome. By northern blot hybridizations we found that these genes are differentially regulated. ATGER1 was expressed during germination, like wheat germin, but also in leaves whereas ATGER2 transcripts were exclusively found in developing embryos, like wheat pseudo-germin. ATGER3 mRNAs were found in leaves and flowers and their abundance was shown to vary during the circadian cycle.
Plant Mol Biol 1997 Nov
PMID:cDNA sequence, genomic organization and differential expression of three Arabidopsis genes for germin/oxalate oxidase-like proteins. 934 69

We have isolated an endogenous positive inotropic factor (EPIF) from porcine left heart ventricular tissue, which demonstrated to have only weak digitalis-like properties including the inhibition of myocardial Na+,K(+)-ATPase. EPIF completely lacks digitalis-like toxicity such as after-contractions in larger doses. In our recent studies, we have demonstrated that EPIF produces a decrease in the amplitude of the post-rest rapid cooling contracture which indicated that EPIF may release Ca2+ from the sarcoplasmic reticulum. In the present study, the effects of EPIF were investigated on the Ca2+ uptake and release properties of SR enriched membrane vesicles from rat heart. At pH 6.8 and in the presence of oxalate, EPIF dose-dependently inhibited the ATP-dependent uptake of Ca2+ by SR vesicles. Concentrations as low as 25 ul (in 1 mL uptake medium) of EPIF caused a 45-47% reduction in the uptake of Ca2+ within 3-4 min. Increases in EPIF concentration to 50 ul/mL caused additional reduction of only 15-20% in the uptake of Ca2+. Concentrations of 25 ul/mL of EPIF had little or no effects on passive release of actively loaded Ca2+ in SR vesicles. On doubling the concentrations to 50 ul/mL EPIF, however, enhanced the release of Ca2+ by 25-28% during 1-2 min and 44-48% after 4 min of incubation of Ca2+ loaded vesicles in the release medium. Relatively smaller effects of EPIF on Ca2+ release implies that EPIF may mainly lower the uptake of Ca2+ in SR. This reduced uptake of Ca2+ may be explained by the EPIF-induced inhibition of Ca2+ pump.
Mol Cell Biochem 1997 Nov
PMID:An endogenous positive inotropic factor (EPIF) from porcine heart: its effects on sarcoplasmic reticular (SR) Ca2+ metabolism. 940 58


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