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排序方式: 共有137条查询结果,搜索用时 406 毫秒
111.
Finci L Ferraro M Kobayashi Y Gregorio Jd Moussa I Albiero R Di L Kobayashi N Martini G Tucci G Recchia M Di Mario C Colombo A 《International journal of cardiovascular interventions》1998,1(1):29-39
Coronary stenting (stent implantation) has evolved over the last 5 years with changes in stent design, stent material and the implantation technique. The use of high-pressure balloon inflation (HP), intravascular ultrasound (IVUS) and appropriate antiplatelet therapy have contributed to the abolishment of the need for subsequent anticoagulation, allowing extended stent applications. We compared results in three groups of patients having stent implantation throughout the period of evolution: group A: no IVUS, no HP, with subsequent anticoagulation treatment (n 3 434); group B: no IVUS, yes HP, without subsequent anticoagulation treatment (n 3 192); and group C: yes IVUS, yes HP, without subsequent anticoagulation treatment (n 3 588). The primary success rates were comparable in all groups. There was a clear change in indications for stenting in groups B and C compared with group A (elective stenting: group A 3 32%; group B 3 66%; group C 3 69%; P < 0.0001), in reference vessel size (group A 3 3.22 3 0.37 mm; group B 3 2.92 3 0.56 mm; group C 3 2.98 3 0.57 mm; P < 0.0001), and for presence of type B2 and C lesions (group A 3 57%; group B 3 72%; group C 3 74%; P < 0.001). The complication rate significantly decreased in group C (group A 3 3.6%; group B 3 4.1%; group C 3 1.2%; P < 0.001) and the mean patient hospital stay decreased to 2 days in groups B and C due to the abolition of the need for anticoagulant treatment. The angiographic restenosis rate increased in groups B and C (group A 3 20%; group B 3 34%; group C 3 32%; P < 0.001). The need for a repeat procedure increased as stenting of more complex lesions and smaller vessels was attempted: target lesion revascularization (TLR) was performed in 16% of patients in group A (73/434), in 18% of group B (35/192) and in 22% of group C (129/588) (P 3 0.04 for A versus C). Major cardiac events (MACE) occurred in 142 patients in group A (33%), 60 patients in group B (31%) and in 181 patients in group C (30%). The evolving technique of coronary stenting has expanded the spectrum of indications and range of coronary vessels attempted, and decreased the complication rates and hospital stay. However, in less-favorable subsets, additional improvements are needed to affect the long-term outcome. 相似文献
112.
Todd John B. Recchia Paul A. Parkes-Loach Pamela S. Olsen John D. Fowler Gregory J. S. McGlynn Peter Neil Hunter C. Loach Paul A. 《Photosynthesis research》1999,62(1):85-98
Unlike the and polypeptides of the core light-harvesting complex (LH1) of Rhodobacter (Rb.) sphaeroides, the and polypeptides of the peripheral light-harvesting complex (LH2) of this organism will not form a subunit complex by in vitro reconstitution with bacteriochlorophyll. Guided by prior experiments with the LH1 polypeptides of Rb. sphaeroides and Rhodospirillum rubrum, which defined a set of interactions required to stabilize the subunit complex, a series of mutations to the Rb. sphaeroides LH2 polypeptide was prepared and studied to determine the minimal changes necessary to enable it to form a subunit-type complex. Three mutants were prepared: Arg at position –10 was changed to Asn (numbering is from the conserved His residue which is known to be coordinated to bacteriochlorophyll); Arg at position –10 and Thr at position +7 were changed to Asn and Arg, respectively; and Arg at position –10 was changed to Trp and the C-terminus from +4 to +10 was replaced with the amino acids found at the corresponding positions in the LH1 polypeptide of Rb. sphaeroides. Only this last multiple mutant polypeptide formed subunit-type complexes in vitro. Thus, the importance of the C-terminal region, which encompasses conserved residues at positions +4, +6 and +7, is confirmed. Two mutants of the LH1 polypeptide of Rb. sphaeroides were also constructed to further evaluate the interactions stabilizing the subunit complex and those necessary for oligomerization of subunits to form LH1 complexes. In one of these mutants, Trp at position –10 was changed to Arg, as found in LH2 at this position, and in the other His at position –18 was changed to Val. The results from these mutants allow us to conclude that the residue at the –10 position is unimportant in subunit formation or oligomerization, while the strictly conserved His at –18 is not required for subunit formation but is very important in oligomerization of subunits to form LH1. 相似文献
113.
114.
Mitochondrial DNA sequence variation in the spruce budworm species complex (Choristoneura: Lepidoptera) 总被引:5,自引:0,他引:5
A combination of polymerase-chain-reaction amplification and automated DNA
sequencing was used to survey variation in a species complex of pest
insects, the spruce budworms (Choristoneura fumiferana species group), and
an outgroup species, C. rosaceana. We sequenced an mtDNA region of 1,573 bp
that extends from the middle of cytochrome oxidase subunit I (COI) through
tRNA leucine (UUR) to the end of cytochrome oxidase subunit II. In
addition, we examined levels of intraspecific variation within a 470-bp
region of the COI gene. Choristoneura fumiferana clearly represented the
oldest lineage within its species group, with 2.7%-2.9% sequence divergence
from the other species. In contrast, the four remaining species (C. pinus,
C. biennis, C. occidentalis, and C. orae) had closely related or identical
mtDNA, with < 1% divergence among most of their haplotypes. Despite its
older lineage and widespread geographic distribution, C. fumiferana showed
significantly lower intraspecific genetic diversity than did C.
occidentalis. Choristoneura orae shared haplotypes with C. occidentalis and
C. biennis, and species-level separation of these three species was not
supported. Two divergent, uncommon haplotypes were also found in C.
occidentalis and C. biennis. The divergent haplotype in C. biennis had an
unusually high number of inferred amino acid replacements, suggesting
selective differences between mitochondrial DNA haplotypes.
Transition:transversion ratios in Choristoneura paralleled those found in
Drosophila; transition:transversion ratios were highest in closely related
sequences but decreased with increasing sequence divergence. Nucleotide
composition showed an A+T bias that was near the high end of the range
known for insects. This work illustrates the potential utility of direct
DNA sequencing in assessing population structures, species limits, and
phylogenetic relationships among organisms that have not previously been
subjected to DNA analysis.
相似文献
115.
Williams JG Ojaimi C Qanud K Zhang S Xu X Recchia FA Hintze TH 《American journal of physiology. Heart and circulatory physiology》2008,294(6):H2516-H2523
The aim of this study was to examine the role of nitric oxide (NO) in the control of cardiac metabolism at 60 days of pregnancy (P60) in the dog. There was a basal increase in diastolic coronary blood flow during pregnancy and a statistically significant increase in cardiac output (55 +/- 4%) and in cardiac NOx production (44 +/- 4 to 59 +/- 3 nmol/min, P < 0.05). Immunohistochemistry of the left ventricle showed an increase in endothelial nitric oxide synthase staining in the endothelial cells at P60. NO-dependent coronary vasodilation (Bezold-Jarisch reflex) was increased by 20% and blocked by N(G)-nitro-l-arginine methyl ester (l-NAME). Isotopically labeled substrates were infused to measure oleate, glucose uptake, and oxidation. Glucose oxidation was not significantly different in P60 hearts (5.4 +/- 0.5 vs. 6.2 +/- 0.4 micromol/min) but greatly increased in response to l-NAME injection (to 19.9 +/- 0.9 micromol/min, P < 0.05). Free fatty acid (FFA) oxidation was increased in P60 (from 5.3 +/- 0.6 to 10.4 +/- 0.5 micromol/min, P < 0.05) and decreased in response to l-NAME (to 4.5 +/- 0.5 micromol/min, P < 0.05). There was an increased oxidation of FFA for ATP production but no change in the respiratory quotient during pregnancy. Genes associated with glucose and glycogen metabolism were downregulated, whereas genes involved in FFA oxidation were elevated. The acute inhibition of NO shifts the heart away from FFA and toward glucose metabolism despite the downregulation of the carbohydrate oxidative pathway. The increase in endothelium-derived NO during pregnancy results in a tonic inhibition of glucose oxidation and reliance on FFA uptake and oxidation to support ATP synthesis in conjunction with upregulation of FFA metabolic enzymes. 相似文献
116.
Clerico A Recchia FA Passino C Emdin M 《American journal of physiology. Heart and circulatory physiology》2006,290(1):H17-H29
The discovery of cardiac natriuretic hormones required a profound revision of the concept of heart function. The heart should no longer be considered only as a pump but rather as a multifunctional and interactive organ that is part of a complex network and active component of the integrated systems of the body. In this review, we first consider the cross-talk between endocrine and contractile function of the heart. Then, based on the existing literature, we propose the hypothesis that cardiac endocrine function is an essential component of the integrated systems of the body and thus plays a pivotal role in fluid, electrolyte, and hemodynamic homeostasis. We highlight those studies indicating how alterations in cardiac endocrine function can better explain the pathophysiology of cardiovascular diseases and, in particular of heart failure, in which several target organs develop a resistance to the biological action of cardiac natriuretic peptides. Finally, we emphasize the concept that a complete knowledge of the cardiac endocrine function and of its relation with other neurohormonal regulatory systems of the body is crucial to correctly interpret changes in circulating natriuretic hormones, especially the brain natriuretic peptide. 相似文献
117.
Cytokines are not a requisite part of the pathophysiology leading to cardiac decompensation 总被引:6,自引:0,他引:6
Recchia FA Bernstein RD Sehgal PB Ferreri NR Hintze TH 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》2000,223(1):47-52
An increase in circulating levels of proinflammatory cytokines has been proposed as an important pathogenic factor contributing to cardiac injury during chronic heart failure. To determine whether plasma levels of the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) increase during pacing-induced heart failure, we paced the hearts of seven dogs at 210 beats/min for 3 weeks and at 240 beats/min for an additional week to induce severe clinical signs of cardiac decompensation. Hemodynamic measurements and blood samples from the aorta and coronary sinus (CS) were taken at control, at 3 weeks, and in end-stage failure. Decompensated heart failure occurred at 29 +/- 1.8 days, when left ventricular (LV) end-diastolic pressure was 25 +/- 1.3 mmHg, LV systolic pressure was 92 +/- 4 mmHg, mean arterial pressure was 77 +/- 3 mmHg, and dP/dtmax was 1219 +/- 73 (all P < 0.05 vs control). Arterial concentration of IL-6 was 12 +/- 4.0 U/ml at control, 11 +/- 2.7 U/ml at 3 weeks, and 10 +/- 1.7 U/ml in end-stage failure (NS). At the same time points, IL-6 in CS plasma was 12 +/- 3.5, 13 +/- 2.8 and 11 +/- 2.4 U/ml, respectively (NS vs control and vs arterial concentrations). TNF-alpha did not reach detectable concentrations in arterial or CS blood at any time. TNF-alpha and IL-6 concentrations did not increase in arterial blood, were not released in the CS from the heart during the development of pacing-induced heart failure, and can not universally be implicated in the pathogenesis of all forms of cardiac dysfunction. Our findings are consistent with other data from patients in which severe heart failure was not associated with increased levels of circulating cytokines. 相似文献
118.
Secretion of a human collagen alpha1(I) chain fragment was achieved in Hansenula polymorpha using the native alpha1(I) procollagen secretory signal sequence. The N-terminal propeptide in the fragment was cleaved off during secretion, yielding the N-terminus of mature alpha1(I) collagen. In Pichia pastoris transformants, the expression of the fragment could be detected on RNA-level, but the product could not be determined extracellularly. After fusion of the fragment with a myc-HIS6 epitope, the intact product was found intracellularly. The difference in the extracellular level of the protein between the two expression hosts is most likely caused by difference in secretion efficiency. 相似文献
119.
Parkes-Loach PS Law CJ Recchia PA Kehoe J Nehrlich S Chen J Loach PA 《Biochemistry》2001,40(19):5593-5601
PufX, the protein encoded by the pufX gene of Rhodobacter capsulatus and Rhodobacter sphaeroides, has been further characterized. The mature forms of these proteins contain 9 and 12 fewer amino acids, respectively, at the C-terminal end of the protein than are encoded by their pufX genes. To identify the portion of PufX responsible for inhibition of LH1 formation in reconstitution experiments, different regions (N-terminus and several core regions containing different lengths of the C-terminus) of Rb. sphaeroides and Rb. capsulatus PufX were chemically synthesized. Neither the N- nor C-terminal polypeptides of Rb. sphaeroides were inhibitory to LH1 reconstitution. However, all core segments were active, causing 50% inhibition at a concentration ratio of between 3:1 and 6:1 relative to the LH1 alpha-polypeptides whose concentrations were 3-4 microM. CD measurements indicated that the core segment containing 39 amino acids of Rb. sphaeroides PufX exhibited 47% alpha-helix in trifluoroethanol while the core segment containing 43 amino acids of Rb. capsulatus PufX exhibited 59 and 55% alpha-helix in trifluoroethanol and in 0.80% octylglucoside in water, respectively. Approximately 50% alpha-helix was also indicated by a PHD (Burkhard-Rost) structure prediction. Binding of bacteriochlorophyll to these PufX core segments is implicated. 相似文献
120.
In this work, we present evidence that indicates that RuvABC proteins resolve Holliday junctions in a way that prevents dimer formation in vivo. First, although arrested replication forks are rescued by recombinational repair in cells deficient for the Rep helicase, rep mutants do not require the XerCD proteins or the dif site for viability. This shows that the recombination events at arrested replication forks are generally not accompanied by the formation of chromosome dimers. Secondly, resolution of dimers into monomers is essential in the rep ruv strain because of an increased frequency of RecFOR recombination events in the chromosome of this mutant. This suggests that, in the absence of the Ruv proteins, chromosomal recombination leads to frequent dimerization. Thirdly, dif or xerC mutations increase the UV sensitivity of ruv-deficient cells 100-fold, whereas they do not confer UV sensitivity to ruv+ cells. This shows that recombinational repair of UV lesions is not accompanied by dimer formation provided that the RuvABC proteins are active. The requirement for dimer resolution in ruv strains is suppressed by the expression of the RusA Holliday junction resolvase; therefore, RusA also prevents dimer formation. We conclude that the inviability arising from a high frequency of dimer formation in rep or UV-irradiated cells is only observed in the absence of known enzymes that resolve Holliday junctions. 相似文献