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Biomedical subjects

R F Kelly

Publications and source records attributed to R F Kelly.

At least 19 recordsLinked to original sources
PubMed2005

Effect of preoperative pulmonary artery pressure on early survival after lung transplantation for idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is the second largest indication for lung transplantation worldwide. Average 90-day mortality rates for this procedure are 22%. It is unclear what factors predispose patients with IPF to this increased early posttransplant mortality. Pulmonary hypertension may increase the risk of development of early posttransplant complications through several mechanisms. We examined the effect of secondary pulmonary hypertension on 90-day mortality after lung transplantation for IPF. METHODS: An International Society for Heart and Lung Transplant Registry cohort study of 830 patients with IPF transplanted from January 1995 to June 2002 was undertaken. Risk factors were assessed individually and adjusted for confounding by a multivariable logistic regression model. RESULTS: In the univariate analysis, pulmonary hypertension and bilateral-lung transplantation were significant risk factors for increased 90-day mortality. Multivariate analysis confirmed that mean pulmonary artery pressure and bilateral procedure remain independent risk factors after adjustment for potential confounders. Recipient age, ischemia time, cytomegalovirus status mismatch, and donor age were not independent risk factors for early mortality. CONCLUSIONS: Bilateral-lung transplantation carries a greater risk of early mortality than single-lung transplantation for IPF. Increasing pulmonary artery pressure is a risk factor for death after single-lung transplantation in IPF. Mean pulmonary artery pressure should be included in the overall risk assessment of patients with IPF evaluated for lung transplantation.

Adult↗
PubMed2001

Assessing coronary blood flow dynamics with the TIMI frame count method: comparison with simultaneous intracoronary Doppler and ultrasound.

This study compared the TIMI frame count (TFC), which has been proposed as a method for quantifying coronary blood flow, with coronary flow and microvascular function measured with intracoronary Doppler and intracoronary ultrasound. Coronary blood flow volume was calculated from coronary blood velocity (by intracoronary Doppler) and lumen area (by intracoronary ultrasound) in the LAD in 46 post-heart transplant patients at baseline and after intracoronary adenosine. TFC correlated significantly with average peak coronary blood velocity (r = -0.42; P = 0.004) and coronary lumen area (r = 0.39; P = 0.008), but not with coronary blood flow volume (r = -0.01; P = 0.96) or the coronary flow reserve response to adenosine (r = 0.09; P = 0.58). In conclusion, TFC is a simple method of assessing coronary blood velocity but not volumetric flow. While TFC does not predict coronary flow reserve, as a measure of velocity it does provide an assessment of basal microvascular tone, information that is complementary to that afforded by flow reserve measurements.

Adult↗
PubMed2001

Postpneumonectomy syndrome after left pneumonectomy.

Postpneumonectomy syndrome, a late complication of pneumonectomy, is secondary to shift of the mediastinum and remaining lung toward the pneumonectomy side, leading to tracheobronchial compression between the vertebral body and the aorta or pulmonary artery. Obstructive airway symptoms are usually due to tracheobronchial tree compression, however, secondary airway malacia may develop. We report herein a case of postpneumonectomy syndrome with secondary bronchomalacia after left pneumonectomy in a patient with normal mediastinal vascular anatomy.

Adult↗
PubMed2001

New developments in percutaneous coronary intervention.

The field of percutaneous coronary intervention continues to progress at a tremendous rate. Advances in techniques, in device technology, and in adjunctive therapy have increased significantly the number of patients who may benefit from angioplasty and have increased the early and long-term success rates of these procedures. Future progress in radiation therapy, IIb/IIIa inhibitors, stent design, and other novel approaches undoubtedly will offer further improvements in the capability of coronary interventions to help patients live longer and feel better.

Angioplasty, Balloon, Coronary↗
PubMed2001

Reaction of acylated homoserine lactone bacterial signaling molecules with oxidized halogen antimicrobials.

Oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. Recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in Pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. This study was conducted to investigate the potential for oxidized halogens to react with acylated homoserine lactone-based signaling molecules. Acylated homoserine lactones containing a 3-oxo group were found to rapidly react with oxidized halogens, while acylated homoserine lactones lacking the 3-oxo functionality did not react. The Chromobacterium violaceum CV026 bioassay was used to determine the effects of such reactions on acylated homoserine lactone activity. The results demonstrated that 3-oxo acyl homoserine lactone activity was rapidly lost upon exposure to oxidized halogens; however, acylated homoserine lactones lacking the 3-oxo group retained activity. Experiments with the marine alga Laminaria digitata demonstrated that natural haloperoxidase systems are capable of mediating the deactivation of acylated homoserine lactones. This may illustrate a natural defense mechanism to prevent biofouling on the surface of this marine alga. The Chromobacterium violaceum activity assay illustrates that reactions between 3-oxo acylated homoserine lactone molecules and oxidized halogens do occur despite the presence of biofilm components at much greater concentrations. This work suggests that oxidized halogens may control biofilm not only via a cidal mechanism, but also by possibly interfering with 3-oxo acylated homoserine lactone-based cell signaling.

4-Butyrolactone↗
PubMed2000

Utilization of coronary angiography and revascularization after acute myocardial infarction in men and women risk stratified by the American College of Cardiology/American Heart Association guidelines.

OBJECTIVES: We sought to determine whether men and women are equally likely to receive coronary angiography and revascularization after acute myocardial infarction (AMI) when they are risk stratified according to American College of Cardiology/American Heart Association (ACC/AHA) practice guidelines for post-MI care. BACKGROUND: Several previous studies have suggested that women may undergo angiography and revascularization procedures less frequently than men. METHODS: In 439 consecutive patients admitted to a public hospital with AMI, rates of coronary angiography and revascularization were compared in men and women categorized, according to ACC/AHA practice guidelines, as having strong (class I or IIa) or weaker (class IIb) indications for angiography. RESULTS: Women were older and more likely to be diabetic or hypertensive, but men and women were equally likely to meet class I/IIa criteria for post-MI angiography (both 51%). Angiography rates were nearly identical in men and women overall (63% vs. 64%), as well as in patients in class I/IIa (80% vs. 82%) and class IIb (46% vs. 46%) (all p > 0.80, with >80% power to detect important differences); the only multivariate predictors of post-MI angiography were age and ACC/AHA class. Significant coronary artery disease was equally prevalent in men and women undergoing angiography, and men and women were equally likely to undergo revascularization, whether they were in class I/IIa (both 55%, p = 0.90) or class IIb (59% vs. 58%, p = 0.88). No significant differences in mortality were noted between men and women. CONCLUSIONS: Despite being older and having more risk factors than men, women were equally likely to undergo coronary angiography and revascularization procedures after AMI, and they had in-hospital clinical outcomes that were at least as favorable.

Adult↗
PubMed2000

Conservative management of postoperative chylothorax using somatostatin.

Chylothorax is a rare but serious postoperative complication of thoracic surgical procedures. We report the case of a 77-year-old man who underwent a coronary artery bypass procedure using a left internal mammary artery pedicle graft. A permanent pacemaker was required postoperatively. A persistent postoperative chylothorax developed necessitating continuous drainage and conservative management. Somatostatin was instituted when after 1 week this management failed to resolve the chylothorax. This led to rapid cessation of chyle production. Enteral feeding was reinstituted without complication and surgical intervention was avoided.

Aged↗
PubMed2000

Current strategies in lung preservation.

Current methods of lung preservation allow for effective, expeditious transplantation as a treatment for end-stage pulmonary disease. However, the utilization of hypothermia, hyperkalemia, and pulmonary artery distension as a single rapid flush for perfusion is less than ideal. All these interventions result in increased pulmonary vascular resistance and suboptimal preservation of lung function. The ability to preserve lungs for longer time intervals and with less risk of tissue injury would provide significant advantages. There would be a greater likelihood that rare size or blood types could find matches by enlarging the area of organ distribution. Optimal preservation would also improve the perioperative outcomes in regard to primary graft failure and subsequently reduce the later complication of chronic rejection and graft lung dysfunction. Finally, through a better understanding of the mechanisms of lung injury during preservation and by developing means to limit the injury, it would be possible to utilize organs from donors that at this time would not be considered optimal. This would increase the donor pool without compromising the recipient's outcome.

Animals↗
PubMed1997

Effect of coronary angioplasty on QT dispersion.

Increased QT dispersion (QTmax-QTmin [QTd]) reflects inhomogeneous ventricular repolarization that may provide a substrate for serious arrhythmias and is associated with adverse clinical outcomes in patients with heart disease. Effective treatment of acute myocardial infarction or ventricular arrhythmias may reduce QTd, but the effect of coronary revascularization on QTd in patients without these conditions is unknown. In this study, QTd was measured before and 4 and 24 hours after successful angioplasty in 94 patients without ongoing symptomatic myocardial ischemia or malignant arrhythmias. QTd decreased from 434 +/- 17 msec before angioplasty to 354 +/- 15 msec 4 hours (p < 0.05) and 33 +/- 14 msec 24 hours after angioplasty (p < 0.05). QTd was improved in 64% of patients, worse in 28%, and unchanged in 8%. Thus angioplasty significantly improves QTd. This may reflect increased myocardial perfusion and may be inherently beneficial by reducing the propensity for arrhythmias.

Aged↗
PubMed1996

Clonally diverse rfb gene clusters are involved in expression of a family of related D-galactan O antigens in Klebsiella species.

Klebsiella species express a family of structurally related lipopolysaccharide O antigens which share a common backbone known as D-galactan I. Serotype specificity results from modification of D-galactan I by addition of domains of altered structure or by substitution with O-acetyl and/or alpha-D-Galp side groups with various linkages and stoichiometries. In the prototype, Klebsiella serotype O1, the his-linked rfb gene cluster is required for synthesis of D-galactan I, but genes conferring serotype specificity are unlinked. The D-galactan I part of the O polysaccharide is O acetylated in Klebsiella serotype O8. By cloning the rfb region from Klebsiella serotype O8 and analyzing the O polysaccharide synthesized in Escherichia coli K-12 hosts, we show that, like rfbO1, the rfbO8 region directs formation of unmodified D-galactan I. The rfbAB genes encode an ATP-binding cassette transporter required for export of polymeric D-galactan I across the plasma membrane prior to completion of the lipopolysaccharide molecule by ligation of the O polysaccharide to lipid A-core. Complementation experiments show that the rfbAB gene products in serotypes O1 and O8 are functionally equivalent and interchangeable. Hybridization experiments and physical mapping of the rfb regions in related Klebsiella serotypes suggest the existence of shared rfb genes with a common organization. However, despite the functional equivalence of these rfb gene clusters, at least three distinct clonal groups were detected in different Klebsiella species and subspecies, on the basis of Southern hybridization experiments carried out under high-stringency conditions. The clonal groups cannot be predicted by features of the O-antigen structure. To examine the relationships in more detail, the complete nucleotide sequence of the serotype O8 rfb cluster was determined and compared with that of the serotype O1 prototype. The nucleotide sequences for the six rfb genes showed variations in moles percent G+C values and in the values for nucleotide sequence identity, which ranged from 66.9 to 79.7%. The predicted polypeptides ranged from 64.3% identity (78.4% total similarity) to 94.3% identity (98.0% similarity). The results presented here are not consistent with dissemination of the Klebsiella D-galactan I rfb genes through recent lateral transfer events.

Antigens, Bacterial↗
PubMed1996

Structure of the core oligosaccharide in the serotype O8 lipopolysaccharide from Klebsiella pneumoniae.

Two classes of mutants with O-antigen-deficient lipopolysaccharides were isolated from the serotype O8 reference strain, belonging to Klebsiella pneumoniae subspecies ozaenae. These mutants were selected by resistance to bacteriophage KO1-2, which recognizes and lyses strains with lipopolysaccharide molecules containing the D-galactan II O antigen. Strain RFK-11 contains a defect in O-antigen synthesis and has a complete core, including the attachment site for O antigen. This mutation is complemented by a plasmid carrying the rfb (O-antigen biosynthesis) gene cluster from the related K. pneumoniae serotype O1. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the lipopolysaccharide from strain RFK-9 has a mobility typical of deep-rough lipopolysaccharide. RFK-9 lipopolysaccharide lacks the attachment site for O antigen. Lipopolysaccharides from strains RFK-9 and RFK-11 were isolated, and their structures were determined by methylation analyses, muclear magnetic resonance spectroscopy, and mass spectroscopy. The deduced O8 core oligosaccharide includes the partial core structure reported for the K. pneumoniae subspecies pneumoniae serotype O1 lipopolysaccharide (M. Süsskind, S. Müller-Leonnies, W. Nimmich, H. Brade, and O. Holst, Carbohydr. Res. 269:C1-7, 1995), consistent with the possibility of a conserved core structure within the species. The core oligosaccharide differs from those of the genera Salmonella and Escherichia by the absence of a hexose-containing outer core, the lack of phosphate residues in the inner core, and the presence of galacturonic acid residues.

Antigens, Bacterial↗
PubMed1996

Forage systems for beef production from conception to slaughter: III. Finishing systems.

Fall-weaned Angus calves grazed or were fed different forages during winter followed by 1) N-fertilized tall fescue (Festuca arundinacea Schreb.) grazed alone, 2) bluegrass (Poa pratensis L.)-white clover (Trifolium repens L.) sequence grazed with tall fescue-red clover (Trifolium pratense L.), or 3) bluegrass-white clover sequence grazed with alfalfa (Medicago sativa L.)-orchardgrass (Dactylis glomerata L.). Heifers were supplemented with grain at 1% of BW from April until slaughter in July. One-half of steers were supplemented with grain at 1% of BW from July until slaughter in October. Remaining steers were fed no grain but were finished on corn silage supplemented with .9 kg of soybean meal per steer daily, from October until slaughter in late January. Including alfalfa-orchardgrass in systems during the finishing phase resulted in higher daily and total gains during the grazing period, and carcasses had more marbling and higher USDA quality grades at slaughter compared with carcasses of cattle on systems using fescue-red clover. Correlation of final weight with carcass characteristics was low (r < .5). Performance and carcass characteristics were influenced as much or more by forage consumed during the previous wintering phase as by forage fed during the finishing phase. Wintering cattle on stockpiled fescue-alfalfa or alfalfa-orchardgrass hay generally resulted in higher BW at slaughter and more desirable carcass characteristics than systems using tall fescue alone or in combination with red clover. This was particularly notable in steers that grazed without grain until October and were finished on corn silage plus supplement. Final BW and carcass characteristics in all cattle were improved by full season grazing followed by feeding corn silage, compared with cattle finished with grain on pasture.

Animal Feed↗
PubMed1996

Cardiac endothelin release and infarct size, myocardial blood flow, and ventricular function in canine infarction and reperfusion.

BACKGROUND: The potent vasoconstrictor endothelin-1 (ET) may play an important pathophysiologic role in acute myocardial infarction, but its precise effects are incompletely understood. The purpose of this study was to evaluate the interrelationships between cardiac ET-1 release and infarct size, myocardial blood flow, and ventricular function. METHODS: Fifteen closed chest dogs underwent 3 hours of coronary artery occlusion followed by 3 hours of reperfusion. Coronary sinus and aortic ET-1 levels during occlusion and after reperfusion were determined by radioimmunoassay. Left ventricular function and regional myocardial blood flow were measured by echocardiography and colored microspheres, respectively. Myocardial infarct size was determined by postmortem staining with blue dye and triphenyl tetrazolium chloride. RESULTS: Coronary occlusion and reperfusion produced significant elevations of coronary sinus ET-1 (p < 0.05) and cardiac ET-1 release (p < 0.05), and a trend toward an increase in aortic ET-1 (p = 0.08). A trend toward more ET-1 release was observed in dogs with larger infarcts (p = 0.06), and in dogs with substantial no-reflow in the reperfused territory (p = 0.05). Endothelin-1 release also was associated with increased contractility in nonischemic myocardial segments (p = 0.002), and ET-1 correlated with increased global left ventricular function (p < 0.02). CONCLUSIONS: In this canine model of coronary occlusion and reperfusion, greater increases in cardiac ET-1 release were observed in dogs with larger infarcts, and increased ET-1 release was associated with the no-reflow phenomenon in the reperfused territory. These data suggest that ET-1 release may have adverse consequences in acute myocardial infarction, including a reduction of myocardial blood flow in the reperfused zone after reperfusion and increased contractility in nonischemic myocardium.

Animals↗
PubMed1995

Effect of 100% oxygen administration on infarct size and left ventricular function in a canine model of myocardial infarction and reperfusion.

High oxygen concentrations reduced infarct size in prereperfusion era studies; however, with reperfusion therapy, high oxygen tension carries the theoretical risk of exacerbating reperfusion injury by increasing toxic oxygen-derived free radicals. In this study, two groups of dogs underwent 90 minutes of coronary occlusion and 72 hours of reperfusion. The oxygen group (n = 16) received 100% inspired oxygen from 20 minutes before reperfusion through 3 hours of reperfusion, whereas the room-air group (n = 19) was ventilated with room air. Infarct size (as a percentage of risk area) was reduced by 38% in the oxygen group (26.7% +/- 4.7% vs 43.3% +/- 4.3%; p = 0.017). This benefit was independent of underlying variability in collateral blood flow in individual dogs (p = 0.016 by analysis of covariance [ANCOVA]). Left ventricular ejection fraction was significantly improved in the oxygen group (43% +/- 3% vs 33% +/- 2%; p = 0.008), as was regional function in the infarct zone (p < 0.05). These data suggest that high concentrations of inspired oxygen may also benefit patients with acute myocardial infarction who undergo reperfusion therapy.

Animals↗
PubMed1995

SPECT imaging of fluorine-18.

UNLABELLED: The objective of this work was to determine the potential clinical usefulness of SPECT to image 511-keV annihilation photons. METHODS: A triple-headed gamma camera equipped with ultra-high-energy collimators was used to image 18F. Sensitivity measurements were carried out and the FWHM and FWTM were determined in air and for a unit-density scattering medium. Additionally, tomographic phantom studies were acquired to evaluate image quality. RESULTS: The sensitivities of the three cameras were, for all practical purposes, identical. At a source-to-collimator distance of 100 mm, the FWHM and FWTM were 13 and 29 mm, respectively. A tomographic phantom study demonstrated that spheres with a diameter of 20 mm were well resolved when filled with 18F activity and placed inside a water-filled phantom. CONCLUSION: The triple-headed SPECT camera in this investigation is a practical means of acquiring tomographic 18F images. The reconstructed slices were of sufficient quality to be of value in some clinical studies.

Fluorine Radioisotopes↗
PubMed1993

Candida thrombosis of the innominate vein with septic pulmonary emboli.

Thrombosis of central veins has become more prevalent because of increased use of long-term central venous catheterization. Candida superinfection of the thrombus can occur particularly in patients on long-term antibiotic therapy and on parenteral nutrition. Removal of the catheter, thrombolytic therapy, anticoagulation, and antifungal therapy with amphotericin B will usually eradicate the candidemia and restore venous patency. Occasionally this therapeutic regimen fails. This case report illustrates such a failure in which multiple pulmonary emboli could have caused death. Surgical thrombectomy of the innominate vein effectively removed the source of the Candida sepsis and maintained patency of a major vein. Thrombectomy should be considered as a therapeutic option in septic central vein thrombosis.

Adult↗
PubMed1993

Structural variation in the O-specific polysaccharides of Klebsiella pneumoniae serotype O1 and O8 lipopolysaccharide: evidence for clonal diversity in rfb genes.

The O-polysaccharide fraction of the lipopolysaccharide from Klebsiella pneumoniae serotype O8 was found to comprise two galactose-containing homopolymers. Structural analysis, using chemical and high-field nuclear magnetic resonance (NMR) techniques, established that the K. pneumoniae O8 polysaccharides are composed of the linear, disaccharide repeating units [formula: see text] K. pneumoniae O8 mutant RFK-1 was isolated by resistance to phage KO1-2; strain RFK-1 expressed only D-galactan I-OAc. The 1H- and 13C-NMR resonances from this O-polysaccharide indicate that all of the O-acetyl groups within the K. pneumoniae O8 polysaccharide are carried on D-galactan I and O-acetylation occurs only on the beta-D-galactofuranose residues; 60% of the available beta-D-galactofuranose residues are non-acetylated. The O-acetylation of the remaining residues is equally distributed between the O-2 and O-6 positions. The carbohydrate backbone structures in the O8 polysaccharide are identical to D-galactan I and II expressed by K. pneumoniae O1, accounting for the antigenic cross-reaction between strains belonging to serotypes O1 and O8. However, the O1 polysaccharides are not acetylated and the O-acetyl groups present in the K. pneumoniae serotype O8 polysaccharides provide a structural basis for their recognition as distinct serotypes. The rfb (O-polysaccharide biosynthesis) gene cluster of K. pneumoniae serotype O1 determines the synthesis of D-galactan I. rfbKpO1-specific gene probes were used to examine conservation in the rfb gene clusters of other K. pneumoniae serotypes which produce D-galactan I. Six O1 strains were examined and all showed hybridization with rfbKpO1 probes under conditions of high stringency. Three serotype O2 strains produce D-galactan I and these strains also contained DNA sequences recognized by rfbKpO1 probes under high stringency. The physical maps of these homologous rfb chromosomal regions showed some polymorphism. Surprisingly, the rfbKpO8 region from K. pneumoniae serotype O8 was only recognized by rfbKpO1 probes under low-stringency hybridization conditions, providing evidence for two substantially different clonal groups of rfb genes from K. pneumoniae strains with structurally related O-antigens.

Acetylation↗