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Replacement
Kinds of Replacement Terms modified by Replacement Selected AbstractsPOTASSIUM HYDROXIDE REPLACEMENT FOR LYE (SODIUM HYDROXIDE) IN TOMATO PEELINGJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2006D.J. DAS ABSTRACT Lye (sodium hydroxide [NaOH]) peeling is the most common method for peeling tomatoes in the Midwest U.S. With the rise in the cost of NaOH and the associated disposal problems, alternative methods for peeling need to be examined. Solutions of NaOH, potassium hydoxide (KOH) and calcium hydroxide (Ca[OH]2) at different concentrations were compared to determine their efficacy as peeling agents. Ca(OH)2 was ineffective as a peeling agent because of its low solubility. KOH produced peeling equivalent to NaOH, but at half the normality. A lower normality is needed because of the increased reactivity of KOH compared to NaOH. This is further demonstrated by the addition of salts to the solution. The use of KOH instead of NaOH may result in cost savings and decreased waste disposal problems. [source] STEVIOSIDE AS A REPLACEMENT OF SUCROSE IN PEACH JUICE: SENSORY EVALUATIONJOURNAL OF SENSORY STUDIES, Issue 5 2001GIUSEPPINA PAOLA PARPINELLO ABSTRACT The suitability of stevioside as a sweetener in peach juice was investigated. Comparison between stevioside and sucrose in terms of sweetness, sweet and bitter aftertastes were determined both in water and peach juice. The results demonstrated that 160 mg/L of stevioside may replace 34 g/L of sucrose in juice, with a 25% decrease in calories, without affecting the sensory characteristics of the product. Synergistic and inhibitory effects between sucrose and stevioside were also monitored at different stevioside concentration. A new juice formulation sweetened with a binary mixture of stevioside (160 mg/L) and sucrose (56 g/L) was not significantly different in terms of desirability from a reference product sweetened with 9% sucrose. [source] "UPGRADING" IN CONNECTION WITH GENERATOR REPLACEMENT (A)PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2000Article first published online: 9 OCT 200 No abstract is available for this article. [source] "UPGRADING" IN CONNECTION WITH GENERATOR REPLACEMENT (B)PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2000Article first published online: 9 OCT 200 No abstract is available for this article. [source] TWINNING, INORGANIC REPLACEMENT, AND THE ORGANISM VIEWRATIO, Issue 1 2010S. Matthew Liao In explicating his version of the Organism View, Eric Olson argues that you begin to exist only after twinning is no longer possible and that you cannot survive a process of inorganic replacement. Assuming the correctness of the Organism View, but pace Olson, I argue in this paper that the Organism View does not require that you believe either proposition. The claim I shall make about twinning helps to advance a debate that currently divides defenders of the Organism View, while the claim I shall make about inorganic replacement will help to put the Organism View on a par with its rival views by allowing it to accommodate a plausible intuition that its rivals can accommodate, namely, the intuition that you can survive a process of inorganic replacement. Both claims, I shall also argue, are important for those who are interested in the identity condition of a human organism, even if they do not hold the view that you are essentially an organism. [source] INCIDENCE AND OUTCOMES OF KNEE AND HIP JOINT REPLACEMENT IN VETERANS AND CIVILIANSANZ JOURNAL OF SURGERY, Issue 5 2006Vanessa Wells Background: This article describes the incidence of total knee and hip replacement, and compares post-surgery health status outcomes in veterans and civilians. Methods: The numbers of male veterans and civilians who had a knee and/or a hip replacement in South Australia (1994,2002) were obtained. Standardized morbidity ratios, and odds ratios for age group by veteran/civilian interactions, were calculated. Presurgery and 1-year post-surgery Medical Outcomes Short Form (36) Health Survey, Knee Society and Harris hip scores were completed. Independent samples t -tests were used to compare presurgery scores. ancova models were used to determine any differences between veterans and civilians post-surgery. Results: For veterans, standardized morbidity ratios were 0.987 and 0.715 for knee and hip replacements, respectively (P < 0.0001). Veterans' odds ratios for knee and hip replacements were significantly lower in the 65- to 74-year age group (P < 0.001), similar in the 75- to 84-year and above 85-year age groups for hip replacement, but significantly higher in the above 85-year age group for knee replacement (P < 0.001). Presurgery, veterans reported significantly lower scores (P < 0.003) for knee function. After knee replacement, veterans reported significantly lower Medical Outcomes Short Form (36) Health Survey scores for bodily pain, physical functioning, role , physical, role , emotional, social functioning and physical component summary (P < 0.033). Significantly lower physical functioning, role , physical and physical component summary scores (P < 0.02) were reported by veterans post-surgery for hip replacement. Conclusion: Veterans are delaying joint replacement. Presurgical knee function is worse in veterans. Post-surgery, the veterans are worse off in a number of health status outcomes. [source] FACTORS AFFECTING IMPLANT RETENTION IN INFECTED JOINT REPLACEMENTSANZ JOURNAL OF SURGERY, Issue 10 2007Jean-Claude Theis Background: There is no standard treatment for infected joint replacements. The options available are varied, and treatment choices may pose problems in relation to both efficacy and cost-effectiveness. Methods: A retrospective review of 73 patient records identified in our departmental audit database as infected joint replacements treated at Dunedin Hospital between 1990 and 2000 was carried out. The findings were analysed in terms of outcome of primary treatment, final outcome including prosthesis retention and bacteriology. Results: Of the 73 patients (50 hips and 20 knees), the majority (69%) were managed by primary surgical debridement followed by intravenous antibiotics but about one-third (34%) lost their implants because of infection. Retention of implants was higher in acute infections (85,100%) as opposed to late infections (20,50%). The microbiological analysis showed that Staphylococcus and Streptococcus caused the majority (76%) of infections. Conclusion: In our series, a patient with an infected joint replacement had an approximately similar 30% chance of retaining the original prosthesis, undergoing a successful revision and having no implants in situ at the end of treatment. [source] Pulmonary Regurgitation after Tetralogy of Fallot Repair: Clinical Features, Sequelae, and Timing of Pulmonary Valve ReplacementCONGENITAL HEART DISEASE, Issue 6 2007Naser M. Ammash MD ABSTRACT Pulmonary regurgitation following repair of tetralogy of Fallot is a common postoperative sequela associated with progressive right ventricular enlargement, dysfunction, and is an important determinant of late morbidity and mortality. Although pulmonary regurgitation may be well tolerated for many years following surgery, it can be associated with progressive exercise intolerance, heart failure, tachyarrhythmia, and late sudden death. It also often necessitates re-intervention. Identifying the appropriate timing of such intervention could be very challenging given the risk of prosthetic valve degeneration and the increased risk of reoperation. Comprehensive informed and regular assessment of the postoperative patient with tetralogy of Fallot, including evaluation of pulmonary regurgitation, right heart structure and function, is crucial to the optimal care of these patients. Pulmonary valve replacement performed in an experienced tertiary referral center is associated with low operative morbidity and mortality and very good long-term results. Early results of percutaneous pulmonary valve replacement are also promising. [source] Transcatheter Cardiac Valve Replacement and RepairCONGENITAL HEART DISEASE, Issue 1-2 2006Robert H. Beekman III MD [source] Subvalvular Stenosis After Aortic Valve ReplacementCONGESTIVE HEART FAILURE, Issue 4 2008Jack P. Chen MD First page of article [source] I PREVENT Bacterial Resistance.DERMATOLOGIC SURGERY, Issue 10 2009An Update on the Use of Antibiotics in Dermatologic Surgery BACKGROUND AND OBJECTIVES Prophylaxis may be given to prevent a surgical wound infection, infective endocarditis (IE), or infection of a prosthetic joint, but its use before cutaneous surgery is controversial. Our aim was to review the current literature and provide a mnemonic to assist providers in appropriately prescribing prophylactic antibiotics. METHODS AND MATERIALS We reviewed the current literature, including the new guidelines provided by the American Heart Association (AHA). RESULTS The new AHA guidelines recommend prophylaxis for patients with high risk of an adverse outcome from IE instead of high risk of developing IE. The American Academy of Orthopedic Surgeons and the American Dental Association also provide guidelines. Given the paucity of conclusive studies, prophylaxis against a surgical wound infection is based more on clinical judgment. CONCLUSION The mnemonic we propose, "I PREVENT," represents: Immunosuppressed patients; patients with a Prosthetic valve; some patients with a joint Replacement; a history of infective Endocarditis; a Valvulopathy in cardiac transplant recipients; Endocrine disorders such as uncontrolled diabetes mellitus; Neonatal disorders including unrepaired cyanotic heart disorders (CHDs), repaired CHD with prosthetic material, or repaired CHD with residual defects; and the Tetrad of antibiotics: amoxicillin, cephalexin, clindamycin, and ciprofloxacin. [source] Synthesis and calcium channel modulating effects of modified Hantzsch nitrooxyalkyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(pyridinyl or 2-trifluoromethylphenyl)-5-pyridinecarboxylatesDRUG DEVELOPMENT RESEARCH, Issue 4 2000Ramin Miri Abstract A group of racemic nitrooxyalkyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(pyridinyl or 2-trifluoromethylphenyl)-5-pyridinecarboxylates 8a,o were synthesized using modified Hantzsch reactions. In vitro calcium channel antagonist activities, determined using a guinea pig ileum longitudinal smooth muscle (GPILSM) assay, showed that compounds 8a,o exhibited weaker calcium antagonist activity (10,5 to 10,7 M range) than the reference drug nifedipine (IC50 = 1.43 × 10,8 M). Compounds 8 possessing a C-4 R1 = 2-pyridyl substituent were always more potent than the approximately equiactive analogs having an R1 = 3-pyridyl, 4-pyridyl or 2-CF3 -C6H4 -substituent, within each subgroup of nitrooxyalkyl compounds [R2 = , (CH2)nONO2 (n = 2, 3, 4) or ,CH(CH2ONO2)2]. Although the length of the R2 = ,(CH2)nONO2 substituent (n = 2,4) was not a determinant of smooth muscle calcium antagonist activity when the C-4 R1 -substituent was 2-pyridyl, when R1 was a 3-pyridyl, 4-pyridyl, or 2-CF3 -C6H4 -substituent, the relative potency order with respect to the R2 = ,(CH2)nONO2 substituent was n = 3 and 4 > n = 2. Replacement of the isopropyl substituent of the ester moiety of the calcium antagonist (±)-2-pyridyl 3a by a ,(CH2)nONO2 (n = 2,4) moiety increased calcium antagonist activity on GPILSM by 8-fold. In contrast, replacement of the isopropyl substituent of the ester moiety of the calcium agonists (±)-3-pyridyl 3b, (±)-4-pyridyl 3c or the methyl substituent of the ester moiety of Bay K8644 by a R2 nitrooxyalkyl substituent resulted in abolition of their calcium agonist effects on GPILSM that is replaced by a smooth muscle calcium antagonist effect. These calcium antagonist data support the concept that incorporation of a nitrooxyalkyl ester substituent constitutes a valuable drug design strategy to enhance Hantzsch 1,4-dihydropyridine calcium antagonist and/or abolish calcium agonist effects on smooth muscle. Replacement of the isopropyl (8b,c), or the methyl (8d) group by a ,CH2CH2ONO2 moiety resulted in retention of the cardiac positive inotropic effect where the relative potency order with respect to the C-4 substituent was 2-CF3 -C6H6 - (8d) > 3-pyridyl (8b) , 4-pyridyl (8c). Model hybrid (calcium channel modulation, ·NO release) compounds, that exhibit dual cardioselective agonist / smooth muscle selective antagonist activities, represent a novel type of 1,4-dihydropyridine CC modulator that offers a potential approach to drug discovery targeted toward the treatment of congestive heart failure and for use as probes to study the structure,function relationship of calcium channels. Drug Dev. Res. 51:225,232, 2000. © 2001 Wiley-Liss, Inc. [source] Alcohol Septal Ablation in a Young Patient after Aortic Valve ReplacementECHOCARDIOGRAPHY, Issue 3 2009Fadi G. Hage M.D. A 38-year-old male presented with heart failure symptoms and was diagnosed with aortic valve endocarditis and underlying aortic stenosis in the absence of concentric hypertrophy or bicuspid aortic valve and underwent aortic valve replacement but continued to have symptoms which were then attributed to hypertrophic cardiomyopathy with dynamic left ventricular outflow tract obstruction. He was determined to be unsuitable for myomectomy and underwent successful alcohol septal ablation using transthoracic echocardiographic Doppler and continuous wave velocity monitoring without requiring to cross the aortic valve or to perform transatrial septostomy and left ventricular pressure monitoring. When crossing the aortic valve is a relative or absolute contraindication like in our index case, continuous Doppler velocity recording is a safe and effective alternative approach to monitor the outflow gradient while performing alcohol septal ablation. [source] Rapid Occurrence of Giant Left Ventricular Pseudoaneurysm after Mitral Valve ReplacementECHOCARDIOGRAPHY, Issue 10 2008Sofiene Rekik M.D. Left ventricular pseudoaneurysms are an uncommon and frightening complication after mitral valve replacement. We report the case of a 54-year old woman, having undergone a mitral valve replacement with uneventful postoperative course and normal echocardiographic predischarge control, who was readmitted to hospital, only 16 days later, for rapidly progressing dyspnea, and finally echocardiographically diagnosed to have a massive 8-cm long pseudoaneurysm communicating with the left ventricle through a narrow communication. The patient was proposed for emergency surgery but unfortunately died preoperatively. [source] Aspergillus niger Aortitis after Aortic Valve Replacement Diagnosed by Transesophageal EchocardiographyECHOCARDIOGRAPHY, Issue 5 2006Hamza Duygu M.D. Aspergillus aortitis following cardiac surgery has an important role among the cardiac infections as almost all affected cases result in death. Survival of the patient with Aspergillus aortitis is dependent on early initiation of aggressive medical and surgical treatment. Transesophageal echocardiography proved very useful in the diagnosis of this uncommon case of aortitis. In this paper, we present a patient with aortitis caused by Aspergillus niger that hasn't been reported previously diagnosed by transesophageal echocardiography following cardiac surgery. [source] Reversible, Fine Performance Tuning of an Organometallic Molecular Wire by Addition, Ligand Replacement and Removal of Dicobalt FragmentsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2010Yuya Tanaka Abstract Communication between the two iron centres in (dithienylethyne)diyl complex 1 can be finely tuned by reversible addition to, ligand replacement at and removal from the C,C moiety in 1 of dicobalt fragments Co2(CO)n(PR3)6,n. Performance analysis reveals that disparate mechanisms are in operation for the two systems. In the case of the dicobalt adducts, indirect communication via the dicobalt steppingstone can be finely tuned by controlling the electronic structure of the dicobalt unit. [source] Pseudo-Octahedral Schiff Base Nickel(II) Complexes: Does Single Oxidation Always Lead to the Nickel(III) Valence Tautomer?EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2008Olaf Rotthaus Abstract With the aim of establishing correlations between the ligand structure and the oxidation site in nickel complexes from Schiff base ligands, five ligands and their nickel complexes have been synthesized. The prototypical asymmetric Schiff base ligand HL1 contains both phenol and pyridine pendant arms with a pivotal imine nitrogen atom. Ligands HL2,5 differ from HL1 by either their phenolate para substituent, the hybridization of the pivotal nitrogen atom, and/or the N-donor properties of the pyridine moiety. The five complexes [Ni(L1,5)2] are obtained by treating the corresponding ligands with 0.5 equiv. of Ni(OAc)2·4H2O in the presence of NEt3. X-ray crystal-structure diffraction studies as well as DFT calculations reveal that [Ni(L1,5)2] involves a high-spin nickel(II) ion within a pseudo-octahedral geometry. The two ligands are arranged in a meridional fashion when the pivotal nitrogen atom is an imine {as in [Ni(L1,2)2] and [Ni(L4,5)2]}, while the fac isomer is preferred in [Ni(L3)2] (amino pivotal nitrogen atom). [Ni(L1)2] is characterized by an oxidation potential at ,0.17 V vs. Fc+/Fc. The one-electron-oxidized species [Ni(L1)2]+ exhibits an EPR signal at g = 2.21 attributed to a phenoxyl radical that is antiferromagnetically coupled to a high-spin NiII ion. [Ni(L2)2] differs from [Ni(L1)2] by the phenolate para substituent (a tert -butyl instead of the methoxyl group) and exhibits an oxidation potential that is ca. 0.16 V higher. Compared to [Ni(L1)2]+ the cation [Ni(L2)2]+ exhibits a SOMO that is more localized on the metal atom. The EPR and electrochemical signatures of [Ni(L3)2]+ are similar to those of [Ni(L1)2]+, thus showing that an imino to amino substitution compensates for a methoxy to tert -butyl one. Replacement of the pyridine by a quinoline group in [Ni(L4,5)2] makes the complexes slightly harder to oxidize. The EPR signatures of the cations [Ni(L4,5)2]+ are roughly similar to those of the pyridine analogs [Ni(L1,2)2]+. The oxidation site is thus not significantly affected by changes in the N-donor properties of the terminal imino nitrogen atom.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Towards Cationic Gallium Derivatives: Metallacycles from the Reactions of Organogallium Compounds with Tetraorganodichalcogenoimidodiphosphinates and a New N -(Diphenylthiophosphinyl)thioureato LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2004Virginia Montiel-Palma Abstract The organometallic complexes of general formulae [Me2Ga{,2 - E,E, -[R2P(E)NP(E,)R,2]}] [R = R, = Ph, E = E, = O (1); R = R, = Ph, E = E, = S (2); R = R, = Ph, E = E, = Se (3); R = R, = Ph, E = O, E, = S (4); R = Me, R, = Ph, E = S, E, = O (5)] and [Me2Ga{,2 - S,S, -[Ph2P(S)NC(S)(C9H10N)]}] (6) were obtained by facile methane elimination reactions from GaMe3 and the acidic ligands L1H [(XPPh2)2NH (X = O, S, Se), (OPPh2)(SPPh2)NH, and (OPMe2)(SPPh2)NH] and L2H [Ph2P(S)NHC(S)(C9H10N)] in toluene. Replacement of one phosphorus atom by a carbon atom in the ligand skeleton of L1H gave the new ligand L2H, which, upon reaction with GaMe3, gave compound 6, which shows no significant structural differences with respect to 1,5. Therefore, L2H does not induce partial planarity in the six-membered ring, indicating the necessity for replacing both phosphorus atoms of the ligand by carbon atoms, as in the ,-diketonate-type derivatives, in order to impose ring planarity. Thus, despite originating from a variety of ligands with differing donor atoms and substituents at the phosphorus atoms, all complexes show little structural differences. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Synthesis, Solution-State and Solid-State Structural Characterization of Monocationic Nitrido Heterocomplexes [M(N)(DTC)(PNP)]+ (M = 99Tc, Re; DTC = Dithiocarbamate; PNP = Heterodiphosphane)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2004Cristina Bolzati Abstract Mono-cationic nitrido heterocomplexes of general formula [M(N)(DTC)(PNP)]+ (where M is 99Tc or Re, DTC is the mono-anionic form of a dithiocarbamate ligand, and PNP is a diphosphane ligand with a tertiary amine-containing five-membered spacer) were prepared by ligand-exchange reactions with the labile precursors [M(N)Cl2(PPh3)2] in dichloromethane/alcohol mixtures. The molecular structure of the representative rhenium complex [Re(N)(dedc)(pnp2)][PF6] (1) displays a distorted, square-pyramidal geometry with the dithiocarbamate sulfur and the diphosphane phosphorus atoms spanning the four coordination positions on the equatorial plane. If the additional interactions between the nitrido nitrogen and the weakly bonded transN -diphosphane heteroatom, the molecular geometry can be viewed as pseudo-octahedral. The structure in solution, as established by multinuclear NMR spectroscopy and ESI spectrometry, is monomeric, and identical to that shown in the solid state. Replacement of the phenyl groups on the phosphorous atoms in complexes 1, 2, 5, and 6 with alkyl groups modified neither the course of the reaction nor the composition of the resulting complexes. These results, together with the observation that no symmetrical complexes containing two identical bidentate ligands were produced in these reactions, strongly supports the conclusion that a mixed coordination sphere, composed by a combination of ,-donor and ,-acceptor atoms around the [M,N]2+ group, constitutes a highly stable system. Compounds containing dangling alkyl-substituted groups in the outer sphere (3, 4, 7, and 8) were fully characterized by multinuclear NMR spectroscopy and ESI mass spectrometry. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Plasma membrane Ca2+ -ATPase in the cilia of olfactory receptor neurons: possible role in Ca2+ clearanceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2007Karen Castillo Abstract Olfactory sensory neurons respond to odorants increasing Ca2+ concentrations in their chemosensory cilia. Calcium enters the cilia through cAMP-gated channels, activating Ca2+ -dependent chloride or potassium channels. Calcium also has a fundamental role in odour adaptation, regulating cAMP turnover rate and the affinity of the cyclic nucleotide-gated channels for cAMP. It has been shown that a Na+/Ca2+ exchanger (NCX) extrudes Ca2+ from the cilia. Here we confirm previous evidence that olfactory cilia also express plasma membrane Ca2+ -ATPase (PMCA), and show the first evidence supporting a role in Ca2+ removal. Both transporters were detected by immunoblot of purified olfactory cilia membranes. The pump was also revealed by immunocytochemistry and immunohistochemistry. Inside-out cilia membrane vesicles transported Ca2+ in an ATP-dependent fashion. PMCA activity was potentiated by luminal Ca2+ (K0.5 = 670 nm) and enhanced by calmodulin (CaM; K0.5 = 31 nm). Both carboxyeosin (CE) and calmidazolium reduced Ca2+ transport, as expected for a CaM-modulated PMCA. The relaxation time constant (,) of the Ca2+ -dependent Cl, current (272 ± 78 ms), indicative of luminal Ca2+ decline, was increased by CE (2181 ± 437 ms), by omitting ATP (666 ± 49 ms) and by raising pH (725 ± 65 ms), suggesting a role of the pump on Ca2+ clearance. Replacement of external Na+ by Li+ had a similar effect (, = 442 ± 8 ms), confirming the NCX involvement in Ca2+ extrusion. The evidence suggests that both Ca2+ transporters contribute to re-establish resting Ca2+ levels in the cilia following olfactory responses. [source] The most C-terminal tri-glycine segment within the polyglycine stretch of the pea Toc75 transit peptide plays a critical role for targeting the protein to the chloroplast outer envelope membraneFEBS JOURNAL, Issue 7 2006Amy J. Baldwin The protein translocation channel at the outer envelope membrane of chloroplasts (Toc75) is synthesized as a larger precursor with an N-terminal transit peptide. Within the transit peptide of the pea Toc75, a major portion of the 10 amino acid long stretch that contains nine glycine residues was shown to be necessary for directing the protein to the chloroplast outer membrane in vitro[Inoue K & Keegstra K (2003) Plant J34, 661,669]. In order to get insights into the mechanism by which the polyglycine stretch mediates correct targeting, we divided it into three tri-glycine segments and examined the importance of each domain in targeting specificity in vitro. Replacement of the most C-terminal segment with alanine residues resulted in mistargeting the protein to the stroma, while exchange of either of the other two tri-glycine regions had no effect on correct targeting. Furthermore, simultaneous replacement of the N-terminal and middle tri-glycine segments with alanine repeats did not cause mistargeting of the protein as much as those of the N- and C-terminal, or the middle and C-terminal segments. These results indicate that the most C-terminal tri-glycine segment is important for correct targeting. Exchanging this portion with a repeat of leucine or glutamic acid also caused missorting of Toc75 to the stroma. By contrast, its replacement with repeats of asparagine, aspartic acid, serine, and proline did not largely affect correct targeting. These data suggest that relatively compact and nonhydrophobic side chains in this particular region play a crucial role in correct sorting of Toc75. [source] Role of the surface charges D72 and K8 in the function and structural stability of the cytochrome c6 from Nostoc sp.FEBS JOURNAL, Issue 13 2005PCC 711 We investigated the role of electrostatic charges at positions D72 and K8 in the function and structural stability of cytochrome c6 from Nostoc sp. PCC 7119 (cyt c6). A series of mutant forms was generated to span the possible combinations of charge neutralization (by mutation to alanine) and charge inversion (by mutation to lysine and aspartate, respectively) in these positions. All forms of cyt c6 were functionally characterized by laser flash absorption spectroscopy, and their stability was probed by urea-induced folding equilibrium relaxation experiments and differential scanning calorimetry. Neutralization or inversion of the positive charge at position K8 reduced the efficiency of electron transfer to photosystem I. This effect could not be reversed by compensating for the change in global charge that had been introduced by the mutation, indicating a specific role for K8 in the formation of the electron transfer complex between cyt c6 and photosystem I. Replacement of D72 by asparagine or lysine increased the efficiency of electron transfer to photosystem I, but destabilized the protein. D72 apparently participates in electrostatic interactions that stabilize the structure of cyt c6. The destabilizing effect was reduced when aspartate was replaced by the small amino acid alanine. Complementing the mutation D72A with a charge neutralization or inversion at position K8 led to mutant forms of cyt c6 that were more stable than the wild-type under all tested conditions. [source] A hydrophobic segment within the C-terminal domain is essential for both client-binding and dimer formation of the HSP90-family molecular chaperoneFEBS JOURNAL, Issue 1 2003Shin-ichi Yamada The , isoform of human 90-kDa heat shock protein (HSP90,) is composed of three domains: the N-terminal (residues 1,400); middle (residues 401,615) and C-terminal (residues 621,732). The middle domain is simultaneously associated with the N- and C-terminal domains, and the interaction with the latter mediates the dimeric configuration of HSP90. Besides one in the N-terminal domain, an additional client-binding site exists in the C-terminal domain of HSP90. The aim of the present study is to elucidate the regions within the C-terminal domain responsible for the bindings to the middle domain and to a client protein, and to define the relationship between the two functions. A bacterial two-hybrid system revealed that residues 650,697 of HSP90, were essential for the binding to the middle domain. An almost identical region (residues 657,720) was required for the suppression of heat-induced aggregation of citrate synthase, a model client protein. Replacement of either Leu665-Leu666 or Leu671-Leu672 to Ser-Ser within the hydrophobic segment (residues 662,678) of the C-terminal domain caused the loss of bindings to both the middle domain and the client protein. The interaction between the middle and C-terminal domains was also found in human 94-kDa glucose-regulated protein. Moreover, Escherichia coli HtpG, a bacterial HSP90 homologue, formed heterodimeric complexes with HSP90, and the 94-kDa glucose-regulated protein through their middle-C-terminal domains. Taken together, it is concluded that the identical region including the hydrophobic segment of the C-terminal domain is essential for both the client binding and dimer formation of the HSP90-family molecular chaperone and that the dimeric configuration appears to be similar in the HSP90-family proteins. [source] Role of a highly conserved YPITP motif in 2-oxoacid:ferredoxin oxidoreductase.,FEBS JOURNAL, Issue 21 2001Heterologous expression of the gene from Sulfolobus sp. strain , characterization of the recombinant, variant enzymes 2-Oxoacid:ferredoxin oxidoreductase from Sulfolobus sp. strain 7, an aerobic and thermoacidophilic crenoarchaeon, catalyses the coenzyme A-dependent oxidative decarboxylation of pyruvate and 2-oxoglutarate, a cognate Zn-7Fe-ferredoxin serving as an electron acceptor. It comprises two subunits, a (632 amino acids) and b (305 amino acids). To further elucidate its structure and function, we constructed a gene expression system. The wild-type recombinant enzyme was indistinguishable from the natural one in every criterion investigated. A series of variants was constructed to elucidate the role of the YPITP-motif (residues 253,257) in subunit a, which is conserved universally in the 2-oxoacid:ferredoxin oxidoreductase (OFOR) family. Single amino-acid replacements at Y253 and P257 by other amino acids caused a drastic loss of enzyme activity. T256, the hydroxyl group of which has been proposed to be essential for binding of the 2-oxo group of the substrate in the Desulfovibrio africanus enzyme, was unexpectedly replaceable with Ala, the kcat and Km for 2-oxoglutarate being ,,33% and ,,51%, respectively, as compared with that of the wild-type enzyme. Replacement at other positions resulted in a significant decrease in the kcat of the reaction while the Km for 2-oxoacid was only slightly affected. Thus, the YPITP-motif is essential for the turnover of the reaction rather than the affinity toward 2-oxoacid. [source] In vivo potentiation of human oestrogen receptor , by Cdk7-mediated phosphorylationGENES TO CELLS, Issue 10 2004Saya Ito Phosphorylation of the Ser118 residue in the N-terminal A/B domain of the human oestrogen receptor , (hER,) by mitogen-activated protein kinase (MAPK), stimulated via growth factor signalling pathways, is known to potentiate ER, ligand-induced transactivation function. Besides MAPK, cyclin dependent kinase 7 (Cdk7) in the TFIIH complex has also been found to potentiate hER, transactivation in vitro through Ser118 phosphorylation. To investigate an impact of Cdk7 on hER, transactivation in vivo, we assessed activity of hER, in a wild-type and cdk7 inactive mutant Drosophila that ectopically expressed hER, in the eye disc. Ectopic expression of the wild-type or mutant receptors, together with a green fluorescent protein (GFP) reporter gene, allowed us to demonstrate that hER, expressed in the fly tissues was transcriptionally functional and adequately responded to hER, ligands in the patterns similar to those observed in mammalian cells. Replacement of Ser118 with alanine in hER, (S118A mutant) significantly reduced the ligand-induced hER, transactivation function. Importantly, while in cdk7 inactive mutant Drosophila the wild-type hER, exhibited reduced response to the ligand; levels of transactivation by the hER, S118A mutant were not affected in these inactive cdk7 mutant flies. Furthermore, phosphorylation of hER, at Ser118 has been observed in vitro by both human and Drosophila Cdk7. Our findings demonstrate that Cdk7 is involved in regulation of the ligand-induced transactivation function of hER,in vivo via Ser118 phosphorylation. [source] Impact of land use and land cover change on groundwater recharge and quality in the southwestern USGLOBAL CHANGE BIOLOGY, Issue 10 2005Bridget R. Scanlon Abstract Humans have exerted large-scale changes on the terrestrial biosphere, primarily through agriculture; however, the impacts of such changes on the hydrologic cycle are poorly understood. The purpose of this study was to test the hypothesis that the conversion of natural rangeland ecosystems to agricultural ecosystems impacts the subsurface portion of the hydrologic cycle by changing groundwater recharge and flushing salts to underlying aquifers. The hypothesis was examined through point and areal studies investigating the effects of land use/land cover (LU/LC) changes on groundwater recharge and solute transport in the Amargosa Desert (AD) in Nevada and in the High Plains (HP) in Texas, US. Studies use the fact that matric (pore-water-pressure) potential and environmental-tracer profiles in thick unsaturated zones archive past changes in recharging fluxes. Results show that recharge is related to LU/LC as follows: discharge through evapotranspiration (i.e., no recharge; upward fluxes <0.1 mm yr,1) in natural rangeland ecosystems (low matric potentials; high chloride and nitrate concentrations); moderate-to-high recharge in irrigated agricultural ecosystems (high matric potentials; low-to-moderate chloride and nitrate concentrations) (AD recharge: ,130,640 mm yr,1); and moderate recharge in nonirrigated (dryland) agricultural ecosystems (high matric potentials; low chloride and nitrate concentrations, and increasing groundwater levels) (HP recharge: ,9,32 mm yr,1). Replacement of rangeland with agriculture changed flow directions from upward (discharge) to downward (recharge). Recent replacement of rangeland with irrigated ecosystems was documented through downward displacement of chloride and nitrate fronts. Thick unsaturated zones contain a reservoir of salts that are readily mobilized under increased recharge related to LU/LC changes, potentially degrading groundwater quality. Sustainable land use requires quantitative knowledge of the linkages between ecosystem change, recharge, and groundwater quality. [source] ORIGINAL ARTICLE Laboratory science: Molecular analysis in two Tunisian families with combined factor V and factor VIII deficiencyHAEMOPHILIA, Issue 5 2010H. E. ABDALLAH Summary., Combined factor V (FV) and factor VIII (FVIII) deficiency (F5F8D) is a rare autosomal recessive disorder caused by mutations in LMAN1 or MCFD2 genes which encode proteins that form a complex involved in the transport of FV and FVIII from the endoplasmic reticulum to Golgi apparatus. We report two novel mutations in MCFD2 gene and one recurrent mutation in LMAN1 gene that caused combined FV and FVIII deficiency in two unrelated Tunisian Muslim families. For the first family two patients were homozygous for a new missense mutation Asp81His in exon 3 of MCFD2 and heterozygous for a second new missense mutation Val100Asp in the same exon. Replacement respectively of the hydrophilic Asp residue with hydrophobic positively charged His and of the hydrophobic neutral Val residue with the Asp residue most likely disrupts the MCFD2,LMAN1 interaction, thus leading to the disease phenotype. For the second family a reported Arg202X mutation in exon 5 in the LMAN1 gene was identified in the homozygous state. [source] Replacement of Canonical DNA Nucleobases by Benzotriazole and 1,2,3-Triazolo[4,5- d]pyrimidine: Synthesis, Fluorescence, and Ambiguous Base PairingHELVETICA CHIMICA ACTA, Issue 4 2005Frank Seela The syntheses and the fluorescence properties of 7H -3,6-dihydro-1,2,3-triazolo[4,5- d]pyrimidin-7-one 2,-deoxy- , - D -ribonucleosides (=2,-deoxy-8-azainosine) 3 (N3), 15 (N2), and 16 (N1) as well as of 1,2,3-benzotriazole 2,- O -methyl- , - or - , - D -ribofuranosides 6 (N1) and 24 (N1) are described. Also the fluorescence properties of 1,2,3-benzotriazole 2,-deoxy- , - D -ribofuranosides 4 (N1) and 5 (N2) are evaluated. From the nucleosides 3,6, the phosphoramidites 19, 26a, 26b, and 28 are prepared and employed in solid-phase oligonucleotide synthesis. In 12-mer DNA duplexes, compound 3 shows similar ambiguous base-pairing properties as 2,-deoxyinosine (1), while the nucleosides 4,6 show strong pairing with each other and discriminate very little the four canonical DNA constituents. [source] Interleukin-6 from intrahepatic cells of bone marrow origin is required for normal murine liver regenerationHEPATOLOGY, Issue 1 2002Xavier Aldeguer Interleukin-6 (IL-6) is required for normal liver regeneration, but the specific cellular source of this growth factor is unknown. We investigated whether this signal originates from the resident macrophage, the Kupffer cell. Using a murine model of bone marrow transplantation, we replaced recipient bone marrow,derived cells, including Kupffer cells, with cells of donor genetic phenotype. Recipients deficient in IL-6 (IL-6,/,) were lethally irradiated, then rescued with 107 donor bone marrow cells capable of expressing IL-6 (IL-6+/+). Conversely, IL-6+/+ recipients received IL-6,/, marrow. Successful engraftment was measured by the presence of the Y chromosome SRY locus in the livers of female recipients receiving male marrow, in situ IL-6 expression by Kupffer cells, and up-regulation of IL-6 in splenocytes after activation with lipopolysaccharide (LPS). Kupffer cell isolation in IL-6,/, females receiving IL-6+/+ male marrow clearly showed the presence of the SRY locus and IL-6 disrupted allele, whereas males receiving female marrow demonstrated no SRY or IL-6 signals, confirming the extent of replacement. Replacement of these cells in IL-6,/, mice with IL-6+/+ bone marrow successfully restored the regenerative response after partial hepatectomy (PHx) as indicated by signal transduction and activator of transcription 3 (STAT3) activation and hepatocyte DNA replication. Alternatively, complete replacement of Kupffer cells in IL-6+/+ mice by transplantation with IL-6,/, cells significantly inhibited liver regeneration and was partially restored by administration of IL-6. This investigation demonstrates a paracrine mechanism by which cells of bone marrow origin, most likely Kupffer cells, regulate the regenerative capacity of the hepatocyte through IL-6 expression. [source] Effect of antipsychotic replacement with quetiapine on the symptoms and quality of life of schizophrenic patients with extrapyramidal symptomsHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 7 2006Takahide Taniguchi Abstract Replacement of antipsychotic drugs with quetiapine (QTP) was tried in a naturalistic setting in chronic schizophrenic patients who still showed moderate psychiatric symptoms and either showed extrapyramidal symptoms (EPS) or took anti-parkinson drugs for the EPS. QTP was added on and gradually increased while the previous drugs were tapered and discontinued whenever possible. Clinical symptoms, objective and subjective QOL, and EPS were measured before and 6 months after QTP addition, using Brief Psychiatric Rating Scale (BPRS), Quality of Life Scale (QLS), Schizophrenia Quality of Life Scale (SQLS) and Drug-Induced Extrapyramidal Symptom Scale (DIEPSS), respectively. Twenty-one patients completed the trial and received the assessment. It was found that replacement with QTP-improved clinical symptoms, objective and subjective QOL and EPS. This improvement was equally observed in not only patients who switched to QTP monotherapy (n,=,11) but also patients who took QTP together with reduced small doses (4.4,±,4.3,mg/day) of previous drugs (n,=,11). The results suggest that replacement with QTP improves symptoms as well as objective and subjective QOL in a subgroup of schizophrenia. Copyright © 2006 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||||||||||||||