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At least 793 records · Page 44Linked to original sources
PubMed2006

Health-related quality of life after polypectomy with and without additional surgery.

OBJECTIVE: The objective of this study was to compare the health-related quality of life of patients undergoing simple polypectomy with that of patients undergoing polypectomy with additional surgery. STUDY DESIGN: This was a prospective, multicenter cohort study of adults undergoing sinonasal surgery. METHODS: Eight hundred forty-four patients received simple polypectomy and 1,004 patients received polypectomy with additional surgery. Health-related quality of life was compared at 12 and 36 months after surgery using the Sino-Nasal Outcome Test (SNOT-22). Total SNOT-22 scores may range from zero to 110 with lower scores representing better outcomes. We used linear regression to adjust postoperative SNOT-22 scores for baseline characteristics. When comparing the difference between the two surgical techniques, positive SNOT-22 scores represent a better outcome for those undergoing additional surgery. RESULTS: There were only small differences between the two groups at 12 months (difference in SNOT-22 -0.5; 95% confidence interval [CI]=-2.3-1.3; P=.58) and 36 months after surgery (difference -2.1; 95% CI=-4.4-0.2; P=.08). The additional surgery group had a slightly higher risk of excessive perioperative bleeding (8.6% vs. 6.0%; P=.04) but a slightly lower risk of revision surgery within 36 months (10.4% vs. 13.3%; P=.12). CONCLUSIONS: Nasal polypectomy with additional surgery seems to have no benefit over simple polypectomy in terms of health-related quality of life improvement for patients with nasal polyposis.

Adolescent↗
PubMed1989

Two phases in the addition of a poly(A) tail.

The addition of a poly(A) tail has been examined in a HeLa cell nuclear extract using SV40 late RNAs that end at or near the natural poly(A) site. We find that the addition of a full-length, 200-nucleotide poly(A) tail occurs in two discrete phases. In the first phase, the addition of each adenosine is dependent on the highly conserved sequence AAUAAA. Mutations in that sequence result in an accumulation of products that contain 9 or fewer adenosine residues. In the second phase, poly(A) addition no longer requires AAUAAA but, instead, requires the oligo(A) primer synthesized during the first phase. Thus, RNAs carrying an AAUAAA mutation and a 3'-terminal oligo(A) segment are extended efficiently to full-length poly(A). The transition between phases occurs with the addition of the tenth adenosine residue. An activity exists that limits the length of poly(A) added in the extract to approximately 200 nucleotides. The two phases share at least one component and are likely to involve the same poly(A) polymerase.

HeLa Cells↗
PubMed1999

Escape over a fluctuating barrier with additive and multiplicative noise.

The mean first passage time (MFPT) over the fluctuating potential barrier is investigated in the presence of additive and multiplicative noises. It is shown that the MFPT over the fluctuating potential barrier displays a resonant activation (RA). The effect of the additive and multiplicative noises and the correlation between them on the RA is that the additive and multiplicative noises can weaken the RA; but the correlation between them can enhance it. The susceptibility of the RA to the multiplicative noise is far larger than that to the additive one. In addition, we find that the transition rate (i.e., the inverse of the MFPT) over the fluctuating potential barrier can be suppressed by the positive correlation and show a minimum as the function of the noises' strengths.

Journal Article↗
PubMed2002

Morphological instability and additive-induced stabilization in electrodeposition.

Experiments show that electrodeposited (ED) films exhibit rough surfaces unless the electrochemical bath contains small quantities of molecular "additive" species. We develop a model for ED with additives which shows the suppression of the morphological instability by preferential additive accumulation near surface protrusions due to complex formation and additive codeposition, and subsequent growth site blocking. Linearly stable growth can be achieved over a wide range of deposition flux at sufficiently large additive bulk concentration. We predict the growth conditions necessary for level surfaces, in good agreement with experiments.

Journal Article↗
PubMed1992

Oxidation and reduction of sulfite by chloroplasts and formation of sulfite addition compounds.

After exposing intact chloroplasts isolated from spinach (Spinacia oleracea L. cv Yates) and capable of photoreducing CO(2) at high rates to different concentrations of radioactive sulfite in the light or in the dark, (35)SO(2) and H(2) (35)S were removed from the acidified suspensions in a stream of nitrogen. Remaining activity could be fractionated into sulfate, organic sulfides, and sulfite addition compounds. When chloroplast suspensions contained catalase, superoxide dismutase and O-acetylserine, the oxidation of sulfite to sulfate was slower in the light than the reductive formation of sulfides that exhibited a maximum rate of about 2 micromoles per milligram chlorophyll per hour, equivalent to about 1% of maximum carbon assimilation. Botht the oxidative and the reductive detoxification of sulfite were very slow in the dark. Oxidation was somewhat, but not much, accelerated in the light in the absence of O-acetylserine, which caused a dramatic decrease in the formation of organic sulfides and an equally dramatic increase in the concentration of sulfite addition compounds whose formation was light-dependent. The sulfite addition compounds were not identified. Addition compounds did not accumulate in the dark. In the light, the electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron, decreased not only the reduction, but also the oxidation of sulfite and the formation of addition compounds.

Journal Article↗
PubMed2002

The effect of epistasis on the excess of the additive and nonadditive variances after population bottlenecks.

The effect of population bottlenecks on the components of the genetic variance generated by two neutral independent epistatic loci has been studied theoretically (VA, additive; VD, dominant; VAA, additive x additive; VAD, additive x dominant; VDD; dominant x dominant components of variance). Nonoverdominance and overdominance models were considered, covering all possible types of marginal gene action at the single locus level. The variance components in an infinitely large panmictic population (ancestral components) were compared with their expected values at equilibrium, after t consecutive bottlenecks of equal size N (derived components). Formulae were obtained in terms of allele frequencies and effects at each locus and the corresponding epistatic value. An excess of VA after bottlenecks can be assigned to two sources: (1) the spatiotemporal changes in the marginal average effects of gene substitution alpha(i), which are equal to zero only for additive gene action within and between loci; and (2) the covariance between alpha2(i) and the heterozygosity at the loci involved, which is generated by dominance, with or without epistasis. Numerical examples were analyzed, indicating that an increase in VA after bottlenecks will only occur if its ancestral value is minimal or very small. For the nonoverdominance model with weak reinforcing epistasis, that increase has been detected only for extreme frequencies of the negative allele at one or both loci. With strong epistasis, however, this result can be extended to a broad range of intermediate frequencies. With no epistasis, the same qualitative results were found, indicating that dominance can be considered as the primary cause of an increase in VA following bottlenecks. In parallel, the derived total nonadditive variance exceeded its ancestral value (V(NA) = V(D) + V(AA) + V(AD) + V(DD)) for a range of combinations of allele frequencies covering those for an excess of VA and for very large frequencies of the negative allele at both loci. For the overdominance model, an increase in V(A) and V(NA) was respectively observed for equilibrium (intermediate) frequencies at one or both loci or for extreme frequencies at both loci. For all models, the magnitude of the change of V(A) and V(NA) was inversely related to N and t. At low levels of inbreeding, the between-line variance was not affected by the type of gene action. For the models considered, the results indicate that it is unlikely that the rate of evolution may be accelerated after population bottlenecks, in spite of occasional increments of the derived V(A) over its ancestral value.

Animals↗
PubMed2005

Compatible scales for progressive and additive MRI assessments of haemophilic arthropathy.

The international MRI expert subgroup of the International Prophylaxis Study Group (IPSG) has developed a consensus for magnetic resonance imaging (MRI) scales for assessment of haemophilic arthropathy. A MRI scoring scheme including a 10 step progressive scale and a 20 step additive scale with identical definitions of mutual steps is presented. Using the progressive scale, effusion/haemarthrosis can correspond to progressive scores of 1, 2, or 3, and synovial hypertrophy and/or haemosiderin deposition to 4, 5, or 6. The progressive score can be 7 or 8 if there are subchondral cysts and/or surface erosions, and it is 9 or 10 if there is loss of cartilage. Using the additive scale, synovial hypertrophy contributes 1-3 points to the additive score and haemosiderin deposition contributes 1 point. For osteochondral changes, 16 statements are evaluated as to whether they are true or false, and each true statement contributes 1 point to the additive score. The use of these two compatible scales for progressive and additive MRI assessments can facilitate international comparison of data and enhance the accumulation of experience on MRI scoring of haemophilic arthropathy.

Cartilage, Articular↗
PubMed2005

Improvement of bioinsecticides production through adaptation of Bacillus thuringiensis cells to heat treatment and NaCl addition.

AIMS: The present work aimed to increase yields of delta-endotoxin production through adaptation of Bacillus thuringiensis cells to heat shock and sodium chloride and to investigate their involvements in bioinsecticides production improvement. METHODS AND RESULTS: Growing B. thuringiensis cells were heat treated after different incubation times to study the response of the adaptative surviving cells in terms of delta-endotoxin synthesis. Similarly, adaptation of B. thuringiensis cells to sodium chloride was investigated. Adaptation to combined stressors was also evaluated. When applied separately in the glucose-based medium, 20-min heat treatment of 6-h-old cultures and addition of 7 g l(-1) NaCl at the beginning of the incubation gave respectively 38 and 27% delta-endotoxin production improvements. Heat shock improved toxin synthesis yields, while NaCl addition improved delta-endotoxin production by increasing the spore titres without significant effect on toxin synthesis yields. Cumulative improvements (66%) were obtained by combination of the two stressors at the conditions previously established for each one. Interestingly, when the similar approach was conducted by using the large scale production medium based on gruel and fish meal, 17, 8 and 29% delta-endotoxin production improvements were respectively, obtained with heat shock, NaCl and combined stressors. CONCLUSIONS: Heat treatment of vegetative B. thuringiensis cells and NaCl addition to the culture media improved bioinsecticides production. Heat treatment increased toxin synthesis yields, while addition of NaCl increased biomass production yields. Cumulative improvements of 66 and 29% were obtained in glucose and economic production media, respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: Overproduction of bioinsecticides by B. thuringiensis could be obtained by the combination of heat treatment of vegetative cells and addition of NaCl to the culture medium. This should contribute to a significant reduction of the cost of B. thuringiensis bioinsecticides production and utilization, and also manage for higher toxin content in the bioinsecticides, which is very interesting from a practical point of view because fewer spores would be disseminated into the ecosystem.

Adaptation, Physiological↗
PubMed2006

MHC class IIB alleles contribute to both additive and nonadditive genetic effects on survival in Chinook salmon.

The genes of the major histocompatibility complex (MHC) are found in all vertebrates and are an important component of individual fitness through their role in disease and pathogen resistance. These genes are among the most polymorphic in genomes and the mechanism that maintains the diversity has been actively debated with arguments for natural selection centering on either additive or nonadditive genetic effects. Here, we use a quantitative genetics breeding design to examine the genetic effects of MHC class IIB alleles on offspring survivorship in Chinook salmon (Oncorhynchus tshawytscha). We develop a novel genetic algorithm that can be used to assign values to specific alleles or genotypes. We use this genetic algorithm to show simultaneous additive and nonadditive effects of specific MHC class IIB alleles and genotypes on offspring survivorship. The additive effect supports the rare-allele hypothesis as a potential mechanism for maintaining genetic diversity at the MHC. However, contrary to the overdominance hypothesis, the nonadditive effect led to underdominance at one heterozygous genotype, which could instead reduce variability at the MHC. Our algorithm is an advancement over traditional animal models that only partition variance in fitness to additive and nonadditive genetic effects, but do not allocate these effects to specific alleles and genotypes. Additionally, we found evidence of nonrandom segregation during meiosis in females that promotes an MHC allele that is associated with higher survivorship. Such nonrandom segregation could further reduce variability at the MHC and may explain why Chinook salmon has one of the lowest levels of MHC diversity of all vertebrates.

Alleles↗
PubMed1992

Simultaneous use of 1-hydroxybenzotriazole and copper(II) chloride as additives for racemization-free and efficient peptide synthesis by the carbodiimide method.

In the carbodiimide mediated coupling of Z-Gly-L-Val-OH with H-L-Val-OMe in DMF, the simultaneous use of HOBt and copper(II) chloride as additives was found to give the desired peptide in a high yield without racemization. In the presence of HOBt, reducing the amount of copper(II) chloride produced a higher yield. Besides improving the coupling efficiency as compared with the case using copper(II) chloride alone as an additive, the present procedure offered another advantage for racemization suppression. Thus, even for the couplings where a low level of racemization was observed in the presence of copper(II) chloride, the simultaneous addition of HOBt and copper(II) chloride resulted in the elimination of racemization. The effectiveness of this new procedure using the two carbodiimide additives in the synthesis of biologically active peptides was assessed by the preparation of a protected Leu-enkephalin. In the 4 + 1 segment condensation using HOBt and copper(II) chloride simultaneously as additives, no racemization was detected and the yield was high enough. The elimination of racemization and improvement of coupling efficiency produced by the present procedure can be attributable to a reduced tendency for the activated forms of the carboxyl component to form a 5(4H)-oxazolone by the action of HOBt, and to the prevention of racemization by copper(II) chloride of the small amount of the oxazolone formed which is not eliminated by the action of HOBt alone.

Amino Acid Sequence↗
PubMed1985

Macroaggregate formation in optimal additive red cells.

The formation of macroaggregates weighing up to 9 g was observed in optimal additive red cells. Such aggregates, with a mean wet weight of 3 g, formed progressively during storage and were present in up to 85% of units. They were composed of leucocyte and platelet debris, together with some fibrin. Macroaggregates formation was halved by less stringent centrifugation during preparation and was reduced by use of an optimal additive system in which the additive solution contained citrate. Extra mixing during transfer of the additive solution only delayed aggregate formation. Partial leucocyte depletion or addition of 200,000 KIU of the enzyme inhibitor aprotinin did not prevent macroaggregate formation.

Blood Preservation↗
PubMed1982

Covalent addition of H2O, enzyme substrates and activators to pyrrolo-quinoline quinone, the coenzyme of quinoproteins.

The fluorescence excitation and the adsorption spectrum of 2,7,9-tricarboxy-1H-pyrrolo [2,3-f]quinoline-4,5-dione (pyrrolo-quinoline quinone, PQQ), measured in the pH range 7.0-10.0, are quite different. However, when the temperature of the solution is lowered, the shape and maxima of these spectra become more similar. 1H-NMR in 2H2O revealed a temperature-dependent equilibrium between PQQ and a hydrated form. Evidence is presented that low temperature favours the formation of the fluorescing species which is PQQ, hydrated at the C-5 position. Even further hydration is possible since absorption, fluorescence and NMR spectroscopy of PQQ in borate buffer pH 10.0 reveal additional hydration at the C-4 position, pointing to a dihydrate. PQQ also reacts with quinoprotein enzyme substrates and activators. Spectroscopic measurements showed the existence of 5-alkoxy-5-hydroxy-PQQ and 5-amino-5-hydroxy-PQQ in the presence of alcohols and 2 M NH4Cl, pH 9.0, respectively. In the latter case, the existence of 5-imino-PQQ could also be demonstrated. Addition compounds with amines appear to be unstable. The amines become probably oxidized because pyrrolo-quinoline quinol (PQQH2) was found as the reaction product. On the other hand, an addition compound containing an imino bond could be isolated after addition of urea to a PQQ solution. Spectral characteristics of PQQ and its addition compounds are presented since these data are necessary for the spectral analysis of quinoproteins and the quantitative estimation of coenzyme.

Chemical Phenomena↗
PubMed1982

70-S ribosomes of Escherichia coli have an additional site for deacylated tRNA binding.

Escherichia coli 70-S ribosomes contain a third site for tRNA binding, additional to the A and P sites. This conclusion is based on several findings. Direct measurements showed that in the presence of poly(U), when both A and P sites are occupied by Ac[14C]Phe-tRNAPhe, ribosomes are capable of binding additionally deacylated non-cognate [3H]tRNA. If ribosomes in the preparation are active enough, the total binding of labeled ligands amounted to 2.5 mol/mol ribosomes. In the absence of poly(U), when the A site can not bind, the P site and the 'additional' site can be filled simultaneously with Ac[14C]Phe-tRNAPhe and deacylated [3H]tRNA, or with [3H]tRNA alone; the total binding exceeds in this case 1.5 mol/mol ribosomes. The binding at the 'additional' site is not sensitive to the template. [3H]tRNA bound there is able to exchange rapidly for unlabeled tRNA in solution. Deacylated tRNA is preferred to the aminoacylated one. The binding of AcPhe-tRNAPhe was not observed there at all. The 3'-end adenosine is essential for the affinity. The function of the 'additional' site is not known, but its existence has to be considered when tRNA . ribosome complexes are studied.

Acylation↗
PubMed1991

ADP is a substrate for the AAUAAA-directed poly(A) addition reaction catalyzed by HeLa cell nuclear extracts.

The specific poly(A) addition reaction catalyzed by crude nuclear extracts from HeLa cells can use ADP as efficiently as ATP as the donor of AMP residues. Both the ADP- and ATP-supported reactions require an intact upstream polyadenylation signal sequence element (AAUAAA). The mutated signal sequence (AACAAA) supports neither reaction. The ADP-supported poly(A) addition reaction can be resolved by glycerol gradient centrifugation of the crude nuclear extract into two components which are active when recombined but are inactive individually. The ATP-supported poly(A) addition is reconstituted by recombining the same gradient fractions, but the activity is lower than that supported by ADP, suggesting that an ATP-specific factor has been removed. A 150 mM KCl fraction DEAE-Sepharose of the nuclear extract, also devoid of the ATP-supported poly(A) addition reaction, retains a normal ADP-supported reaction. Together, these data show that ADP is a substrate for polyadenylation, and suggest that different factors might be required to induce ADP- or ATP-specificity in the poly(A) addition reaction.

Adenosine Diphosphate↗
PubMed1995

Structure of metal site in Cd-substituted His117Gly mutant of azurin with and without addition of imidazole derivatives.

The present work uses 111mCd-perturbed angular correlations of gamma-rays (PAC) to investigate the structure of the metal site of the His117Gly mutant of Pseudomonas aeruginosa azurin in aqueous solution and the effect on the structure upon addition of the following exogenous ligands: imidazole, 4-methyl imidazole, 1-methyl imidazole, 2-methyl imidazole and histidine. The nuclear quadrupole interaction of cadmium bound to the mutant without addition of exogenous ligands shows a strong pH dependence with three different nuclear quadrupole interactions consistent with two pKa values at about 7.2 and 8.6 at 2 degrees C. Addition of the imidazole derivatives resulted in a significant change in the PAC spectrum showing that they coordinate. This is in accordance with observations by EPR for the same mutant with copper at the metal site [den Blaauwen, T. & Canters, G. W. (1993) J. Am. Chem. Soc. 115, 1121-1129]. However, whereas EPR and ultraviolet/visual absorption show that the characteristics of the wild-type copper protein are regained by addition of the imidazole derivatives with the exception of the possible bidentates (histidine and histamine), the comparison of the PAC results to model calculations shows that the cadmium ion must be fourfold coordinated in most cases, probably binding an additional water or hydroxide ligand. A fourfold coordination is in contrast to cadmium-substituted wild-type azurin where PAC data inferred a threefold coordination by a Cys and two His residues [Danielsen, E. Bauer, R., Hemmingsen, L., Andersen. M., Bjerrum, M. J., Butz, T., Tröger, W., Canters, G. W., Hoitink, C. W. G., Karlsson, G., Hansson, O. & Messerschmidt, A. (1995) J. Biol. Chem. 270, 573-580]

Azurin↗
PubMed2003

Phytosterol additives increase blood pressure and promote stroke onset in salt-loaded stroke-prone spontaneously hypertensive rats.

1. To assess the effect of dietary phytosterol on stroke and the lifespan of salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP), we investigated the effects of the addition of phytosterol to soybean oil (phytosterol content: 0.3%) on stroke onset, lifespan following onset of stroke and overall lifespan compared with canola oil (phytosterol content: 0.9%). 2. Six-week-old male SHRSP were fed a test diet prepared by the addition of canola oil (CA diet), soybean oil (SO diet), soybean oil plus 0.6% phytosterol (SO + 0.06P diet) or soybean oil plus 4.5% phytosterol (SO + 0.45P diet) as a 10% fat source. 3. Systolic blood pressure (SBP) increased in the SO + 0.06P and SO + 0.45P groups compared with the SO group and the increase was dependent on the amount of phytosterol added, indicating that the addition of phytosterol to soybean oil may promote an increase in SBP in salt-loaded SHRSP. 4. The onset of stroke was shortest in the SO + 0.45P group and survival after the onset of stroke was shortest in the CA group. Consequently, the SO + 0.45P and CA groups showed marked lifespan shortening, indicating that a fivefold greater amount of phytosterol was required to produce an effect equivalent to that of canola oil. 5. Investigation of the mRNA expression of ATP-binding cassette (ABC) transporters involved in intestinal phytosterol absorption indicated significant decreases in the intestinal mRNA expression of Abcg5 and Abcg8 in SHRSP and Wistar-Kyoto rats compared with Wistar rats. 6. In conclusion, the addition of phytosterol to soybean oil elevated SBP and promoted the onset of stroke, which may cause a reduction in survival time. However, a fivefold greater amount of phytosterol was required to produce an effect that was equivalent to the survival time-shortening effect of canola oil. The significant decrease in the intestinal mRNA expression of Abcg5 and Abcg8 in SHRSP may be responsible, at least in part, for the unfavourable effects observed following the addition of phytosterol.

ATP-Binding Cassette Transporters↗
PubMed2004

Role of additional angiography and chemoembolization in patients with hepatocellular carcinoma who achieved complete necrosis following transarterial chemoembolization.

BACKGROUND AND AIMS: Although transarterial chemoembolization (TACE) has been reported to have antitumor effects in patients with hepatocellular carcinoma (HCC), optimal time schedules and follow-up methods have not yet been determined. We therefore prospectively analyzed the effects of additional angiography and chemoembolization on HCC recurrence and survival in patients who underwent TACE and achieved complete necrosis (CN). METHODS: A total of 68 patients who achieved CN after TACE, as assessed using dynamic computed tomography (CT), were randomized into two groups. Patients in the CT group (n = 34) were followed using dynamic CT every 3 months without any further intervention, whereas patients in the angiography group (n = 34) received additional angiography 1 month after achievement of CN. We compared overall survival and disease-free survival between the two groups and analyzed the benefit of additional angiography. RESULTS: The cumulative recurrence rate did not differ between the angiography and CT groups (55%vs 48% at 12 months and 66%vs 67% at 24 months, P = 0.92). The overall survival rates at 12 and 24 months were 88% and 84% in the angiography group, and 88% and 70% in the CT group, respectively (P = 0.57). Of the 34 patients in the angiography group, 27 (79%) suffered from adverse reactions of additional angiography and subsequent chemoembolization, seven (20.6%) experienced serum bilirubin increases of >/=1 mg/dL over baseline, and two (5.9%) developed renal impairment. CONCLUSION: Additional angiography and chemoembolization did not reduce tumor recurrence or improve patient survival in HCC patients who achieved CN, as assessed using dynamic CT, following TACE.

Adult↗
PubMed2006

Additional computed tomography scans in the prone position to distinguish early interstitial lung disease from dependent density on helical computed tomography screening patient characteristics.

BACKGROUND: The purpose of this study was to evaluate the benefit of additional prone CT scanning to helical CT screening to detect early interstitial lung disease (ILD). METHODS: Helical CT screening was performed as an optional test in 1098 subjects during their annual health examination. Subjects with parenchymal abnormalities in the posterior subpleural aspect of the lung were advised to receive additional CT scans in the prone position. The CT images were assessed independently by both a radiologist and a chest specialist without reference to clinical data. RESULTS: Ninety-three subjects (8%) had parenchymal abnormalities in the posterior subpleural aspect of the lung and 75 subjects (7%) received additional CT scans. These revealed 72 dependent densities and three early ILD (0.3%). By multivariate analysis, subjects aged over 70 years, with obesity (BMI >or= 25) and currently smoking (pack years >or= 20) had a tendency to have dependent density on helical CT, the predominant distribution of which was in the middle lung fields. CONCLUSIONS: Additional CT scans were performed in 7% of subjects after abnormal CT screening and three early ILD were detected. Therefore, we recommend that additional CT scans in prone position be performed to detect early ILD after abnormal helical CT screening.

Age Factors↗