Biomedical subjects

R A Kennedy

Publications and source records attributed to R A Kennedy.

At least 19 recordsLinked to original sources

PubMed2005

Training effects of short bouts of stair climbing on cardiorespiratory fitness, blood lipids, and homocysteine in sedentary young women.

OBJECTIVES: To study the training effects of eight weeks of stair climbing on Vo2max, blood lipids, and homocysteine in sedentary, but otherwise healthy young women. METHODS: Fifteen women (mean (SD) age 18.8 (0.7) years) were randomly assigned to control (n = 7) or stair climbing (n = 8) groups. Stair climbing was progressively increased from one ascent a day in week 1 to five ascents a day in weeks 7 and 8. Training took place five days a week on a public access staircase (199 steps), at a stepping rate of 90 steps a minute. Each ascent took about two minutes to complete. Subjects agreed not to change their diet or lifestyle over the experimental period. RESULTS: Relative to controls, the stair climbing group displayed a 17.1% increase in Vo2max and a 7.7% reduction in low density lipoprotein cholesterol (p < 0.05) over the training period. No change occurred in total cholesterol, high density lipoprotein cholesterol, triglycerides, or homocysteine. CONCLUSIONS: The study confirms that accumulating short bouts of stair climbing activity throughout the day can favourably alter important cardiovascular risk factors in previously sedentary young women. Such exercise may be easily incorporated into the working day and therefore should be promoted by public health guidelines.

Adolescent↗

PubMed2003

Construction of a comparative RFLP map of Echinochloa crus-galli toward QTL analysis of flooding tolerance.

To analyze quantitative trait loci (QTLs) affecting flooding tolerance and other physiological and morphological traits in Echinochloa crus-galli, a restriction fragment length polymorphism (RFLP) map was constructed using 55 plants of the F(2) population ( E. crus-galli var. praticola x E. crus-galli var. formosensis). One hundred forty-one loci formed 41 linkage groups. The total map size was 1,468 cM and the average size of linkage groups was 35.8 cM. The average distance between markers was 14.7 cM and the range was 0-37.2 cM. Early comparisons to the genetic maps of other taxa suggest appreciable synteny with buffelgrass ( Pennisetum spp.) and sorghum ( Sorghum spp.). One hundred ninty-one F(2) plants were used to analyze QTLs of flooding tolerance, plant morphology, heading date, number of leaves, and plant height. For flooding tolerance, two QTLs were detected and one was mapped on linkage group 24. Other traits, including plant morphology, heading date, number of leaves, and plant height were highly correlated. Three genomic regions accounted for most of the mapped QTLs, each explaining 2-4 of the significant marker-trait associations. The high observed correlation between the traits appears to result from QTLs with a large contribution to the phenotypic variance at the same or nearby locations.

Chromosome Mapping↗

PubMed2000

Evaluation of the iScreen digital screening system for amblyogenic factors.

BACKGROUND: A digital photoscreener, the iScreen screening system, is now available to detect amblyogenic factors. We carried out a prospective study to evaluate the accuracy of the device in detecting anisometropia, significant refractive error, strabismus and opacities of the ocular media. METHODS: A total of 449 consecutive patients (median age 7 years) from a private pediatric ophthalmology practice underwent screening with the iScreen photoscreener operated by a minimally trained technician. The results were compared to the masked clinical examination of a pediatric ophthalmologist. RESULTS: The iScreen device had a sensitivity of 92.4%, specificity of 89.1%, positive predictive value of 94.1% and false-negative rate of 13.8%. Of the 21 patients with a false-negative result, 12 had myopia of less than -1.50 dioptres. High hyperopia was missed in two patients, high astigmatism in one, unequal cylindrical error in one and strabismus in five. INTERPRETATION: The iScreen digital photoscreener produced accurate and timely screening for potentially amblyogenic defects in the study population.

Adolescent↗

PubMed2000

Plasma atherogenic markers in congestive heart failure and posttransplant (heart) patients.

OBJECTIVES: We hypothesized that plasma factors important for the development of atherosclerosis play a major role in the occurrence of cardiac allograft vasculopathy (CAV). BACKGROUND: Cardiac allograft vasculopathy is a major cause of death among heart transplant recipients, has a poorly understood pathogenesis and has similarities to atherosclerotic coronary disease. METHODS: The study population consisted of 93 postcardiac transplant recipients. Thirty-one patients with congestive heart failure (CHF) and 18 healthy individuals served as control subjects. Posttransplant coronary anatomy was evaluated by angiography and intravascular ultrasound. Laboratory analyses of lipids, homocysteine, vitamin B12 and folate, fibrinogen, von Willebrand factor antigen (vWFAg) and renin were obtained on all participants. RESULTS: Posttransplant patients were found to have elevated serum triglycerides, total cholesterol/ high-density lipoprotein cholesterol ratio, lipoprotein (a), homocysteine, vWFAg, fibrinogen and renin and lower high-density lipoprotein cholesterol. Most of these laboratory atherogenic factors were also elevated to a similar degree in the CHF control population. Although most atherogenic markers were elevated, there was little correlation with CAV severity. Cardiac allograft vasculopathy severity varied with time after transplantation, 3-hydroxy-methyl-glutaryl-coenzyme A reductase inhibitor use and prior cytomegalovirus infection. Even within the normal range, lower RBC folate levels were associated with increased severity of CAV. CONCLUSIONS: The posttransplant course is associated with increased clinical and laboratory atherogenic factors, some of which likely contribute to the severity of coronary vasculopathy. Compared with normal control subjects, many of these markers are already increased in pretransplant CHF patients with or without occlusive coronary artery disease.

Adult↗

PubMed2000

Analgesic efficacy of ketorolac 0.5% ophthalmic solution (Accular) in paediatric strabismus surgery.

This prospective double-blind study was designed to assess the analgesic efficacy of ketorolac 0.5% ophthalmic solution compared with placebo in 30 healthy children undergoing extraocular muscle recession for correction of strabismus. After paracetamol 20 mg.kg-1 preoperatively, a standard anaesthetic was given. There were no significant differences in Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and faces pain scale (FPS) scores, requirement for supplementary analgesia or in postoperative vomiting between the two groups over the following 24 h. This study did not demonstrate improved postoperative analgesia when topical ketorolac eye drops were given in addition to paracetamol. This observed lack of efficacy may reflect difficulties in the use of CHEOPS and FPS in this age group with this pain model.

Child↗

PubMed2000

Mollusc-algal chloroplast endosymbiosis. Photosynthesis, thylakoid protein maintenance, and chloroplast gene expression continue for many months in the absence of the algal nucleus.

Early in its life cycle, the marine mollusc Elysia chlorotica Gould forms an intracellular endosymbiotic association with chloroplasts of the chromophytic alga Vaucheria litorea C. Agardh. As a result, the dark green sea slug can be sustained in culture solely by photoautotrophic CO(2) fixation for at least 9 months if provided with only light and a source of CO(2). Here we demonstrate that the sea slug symbiont chloroplasts maintain photosynthetic oxygen evolution and electron transport activity through photosystems I and II for several months in the absence of any external algal food supply. This activity is correlated to the maintenance of functional levels of chloroplast-encoded photosystem proteins, due in part at least to de novo protein synthesis of chloroplast proteins in the sea slug. Levels of at least one putative algal nuclear encoded protein, a light-harvesting complex protein homolog, were also maintained throughout the 9-month culture period. The chloroplast genome of V. litorea was found to be 119.1 kb, similar to that of other chromophytic algae. Southern analysis and polymerase chain reaction did not detect an algal nuclear genome in the slug, in agreement with earlier microscopic observations. Therefore, the maintenance of photosynthetic activity in the captured chloroplasts is regulated solely by the algal chloroplast and animal nuclear genomes.

Algal Proteins↗

PubMed1997

Removal from the "waiting list" for heart transplantation: a risk factor for sudden death?

METHODS AND RESULTS: Over an 18-month period, the patients on the heart transplantation waiting list at our institution were evaluated to determine if continued listing was appropriate. Ten patients were removed because of significant improvement in clinical status and exercise capacity (n = 9) or because of criteria violation (n = 1). Four of these patients died suddenly and unexpectedly within 4 months of delisting, resulting in a 6-month survival of 60% for the patients removed. During the same period, the 6-month survival for newly listed patients (n = 10) was 80% and that for newly transplanted patients (n = 13) was 92%. An elevated pulmonary capillary wedge pressure (> or = 18 mmHg) was the only clinical or laboratory feature that appeared to distinguish the four patients who died suddenly following delisting. CONCLUSION: The results of this preliminary study suggest that removal of a patient from a heart transplant waiting list may represent a risk for sudden death, particularly in patients with elevated ventricular filling pressures, irrespective of otherwise favorable clinical status and exercise performance.

Adult↗

PubMed1997

Studies on diffusion in alginate gels. II. Effect of acid and subsequent re-exposure to calcium on the diffusion of caffeine and theophylline in alginate gel films.

The aim of this research was to investigate the effect of acid exposure and calcium re-exposure on the diffusion of caffeine and theophylline through calcium alginate gel films. Diffusion was measured using side-by-side glass cells, before and after the films were exposed to simulated gastric fluid (SGF) USP minus pepsin. The permeability increased by about 15-fold for theophylline and 48-fold for caffeine after 5 min SGF exposure. There was no significant further increase by prolonging the exposure time to 4 hr. The diffusion of both drugs was less than through alginate gel films that were not cross-linked with calcium but were gelled in SGF. Treatment of the calcium alginate gel films with SGF depleted the films of all of their calcium content. Calcium alginate gel films that were exposed to SGF for a constant period of 15 min, were re-exposed to 0.34 M calcium chloride solution for periods up to 24 hr. The calcium content returned to 80% of the level in the original calcium alginate films and diffusion was reduced, but not to the level that was observed in the original calcium alginate films. It was concluded that the effect of SGF on calcium alginate was very rapid and that the increase in drug diffusion observed was probably due to removal of calcium from the gel. It was also concluded that the original diffusion properties and calcium content could only be partially regenerated by re-exposing the acid-exposed films to calcium chloride.

Administration, Oral↗

PubMed1996

Coupled Markov chain model: characterization of membrane channel currents with multiple conductance sublevels as partially coupled elementary pores.

A parameterized Markov chain model is developed to represent the characteristics of channel currents that either are the superposition of many single channels or show multiple conductance sublevels. The simplified model takes the form of a set of binary chains that are interdependent according to a simple lumped coupling parameter. When varied, this parameter realizes a range of behaviors from tight coupling to complete independence. Other model parameters describe the intrinsic characteristics of the binary chains. An identification procedure for the model parameters is developed based on hidden Markov modeling ideas but incorporating a novel parameter estimation. The usefulness of the model in analyzing certain types of data is demonstrated with examples of real channel currents.

Animals↗

PubMed1996

Compatibility of propofol, fentanyl, and vecuronium mixtures designed for potential use in anesthesia and patient transport.

STUDY OBJECTIVE: To determine whether propofol emulsion, fentanyl, and vecuronium remain compatible and stable when mixed in clinically appropriate concentrations. DESIGN: Seven separate in vitro experiments. Two different propofol-fentanyl-vecuronium mixtures were formulated. Regular assays of propofol, fentanyl, and vecuronium were performed during a 90-minute infusion period and also during storage of one of the mixtures for 30 days at 4 degrees C, 22 degrees C, and 30 degrees C. Initial and storage pH were determined, and assays of the three drugs were performed when pH of the mixtures was varied between 1.4 and 12.7. Emulsion stability was assessed by measuring immediate and delayed alterations in droplet charge (zeta potential) and size. Finally, samples of the stored mixtures were incubated in culture medium for one week. SETTING: Teaching hospital and university laboratories. MEASUREMENTS AND MAIN RESULTS: Concentrations of the three drugs remained unchanged during infusion. During storage, concentrations of all three drugs were stable for two weeks at 4 degrees C or 22 degrees C, and for several days at 30 degrees C. Initial pH of the two mixtures was 5.1 and 5.3, and pH of the stored mixture increased slowly after 8 days. When the pH of mixtures was greater than or equal to 5.6, concentrations of fentanyl and vecuronium were unstable, but the concentration of propofol remained unchanged. Despite a reduction in zeta potential, immediate droplet size was essentially unchanged. No microbial growth was detected in stored mixtures. CONCLUSION: The propofol, fentanyl, and vecuronium mixtures studied were compatible and stable immediately after mixing. Appropriate in vitro compatibility testing is recommended before clinical evaluation of propofol-opioid or propofol-opioid-muscle relaxant mixtures.

Anesthesia↗

PubMed1996

The effect of the addition of lignocaine on propofol emulsion stability.

The stability of propofol emulsion following the addition of various amounts of lignocaine solution was investigated. The investigations used were macroscopic and microscopic observations and electroacoustic determination of both droplet size and zeta potential. Evidence of emulsion instability was present following the addition of even small amounts of lignocaine. Resultant changes are unlikely to be clinically important following the addition of less than 20 mg of lignocaine to 200 mg of propofol (20 ml of propofol emulsion). It is recommended, however, that anaesthetists consider the possibility of destabilisation of propofol emulsion when adding larger doses of lignocaine, or when there is a delay between formulation and administration of the propofol-lignocaine mixtures.

Anesthetics, Intravenous↗

PubMed1995

Identification and gene expression of anaerobically induced enolase in Echinochloa phyllopogon and Echinochloa crus-pavonis.

Enolase (2-phospho-D-glycerate hydrolase, EC 4.2.1.11) has been identified as an anaerobic stress protein in Echinochloa oryzoides based on the homology of its internal amino acid sequence with those of enolases from other organisms, by immunological reactivity, and induction of catalytic activity during anaerobic stress. Enolase activity was induced 5-fold in anoxically treated seedlings of three flood-tolerant species (E. oryzoides, Echinochloa phyllopogon, and rice [Oryza sativa L.]) but not in the flood-intolerant species (Echinochloa crus-pavonis). A 540-bp fragment of the enolase gene was amplified by polymerase chain reaction from cDNAs of E. phyllopogon and maize (Zea mays L.) and used to estimate the number of enolase genes and to study the expression of enolase transcripts in E. phyllopogon, E. crus-pavonis, and maize. Southern blot analysis indicated that only one enolase gene is present in either E. phyllopogon or E. crus-pavonis. Three patterns of enolase gene expression were observed in the three species studied. In E. phyllopogon, enolase induction at both the mRNA and enzyme activity levels was sustained at all times with a further induction after 48 h of anoxia. In contrast, enolase was induced in hypoxically treated maize root tips only at the mRNA level. In E. crus-pavonis, enolase mRNA and enzyme activity were induced during hypoxia, but activity was only transiently elevated. These results suggest that enolase expression in maize and E. crus-pavonis during anoxia are similarly regulated at the transcriptional level but differ in posttranslational regulation, whereas enolase is fully induced in E. phyllopogon during anaerobiosis.

Amino Acid Sequence↗

PubMed1992

Anaerobic metabolism in plants.

Exposure to oxygen deficits is more widespread in biological systems than is commonly believed. Until recently, the general perception of anaerobic metabolism was often limited to the induction of alcoholic or lactic acid fermentation as the sole biochemical response to hypoxia/anoxia. Developments in the physiology, biochemistry, and molecular biology of anaerobic responses in invertebrates, lower plants, and higher plants have demonstrated that, depending upon the species, anaerobic metabolism may encompass much more than simple glycolytic metabolism. Here, recent progress in elucidating the mechanism(s) determining tolerance versus intolerance to anaerobic environments in higher plants is discussed, drawing most heavily on experimental systems using seeds or seedlings.

Journal Article↗

PubMed1991

Forward-backward non-linear filtering technique for extracting small biological signals from noise.

A novel and computationally efficient, non-linear signal processing technique for reducing background noise to reveal small biological signals is described. The signal estimate is formed by weighting the outputs of a set of causal (forward) and anti-causal (backward) predictors. The weights used to combine the predictors are adaptively determined at each data point to reflect the performance of the respective predictor within a short analysis window. The method is specifically designed for revealing fast transient signals dominated by noise, such as single-channel or post-synaptic currents. Markovian and exponentially decaying signals embedded in the amplifier noise were extracted using this method and compared with the original signals. The results of such simulations demonstrate the advantage of this non-linear method over low-pass filtering. Brief pulses imbedded in a broad-band amplifier noise can be reliably recovered using our non-linear filtering technique. Moreover, the kinetics of a single channel and the time constant of exponentially decaying signals can be measured with acceptable accuracy even when the signals are dominated by noise.

Electronics↗

PubMed1990

Effect of vitamin and mineral supplementation on verbal and non-verbal reasoning of schoolchildren.

In a randomised controlled trial the effect of vitamin and mineral supplementation for seven months on performance in tests of reasoning was studied in 86 schoolchildren aged 11-13. A small, non-significant difference between the control and supplementation groups was found in a non-verbal test. The net difference in change in scores between the active and placebo groups was 2.4 units (95% CI-1.5 to 6.3). This direction of effect was not consistently seen with three other tests of non-verbal reasoning. Vitamin and mineral supplementation does not improve the performance of schoolchildren in tests of reasoning.

Administration, Oral↗

PubMed1990

Botulinum vs adjustable suture surgery in the treatment of horizontal misalignment in adult patients lacking fusion.

Thirty patients were treated with either botulinum toxin or adjustable suture surgery in a prospective, randomized clinical trial. All patients had horizontal deviations greater than 10 prism diopters and absent fusion. Seventeen patients were assigned to toxin treatment, and 13 were assigned to surgical treatment. Follow-up at 6 months after either procedure indicated that surgery was superior, with patient alignment showing a 92.7% average net change, compared with a 50.50% net change in the botulinum-treated group. There was no difference in response between those patients with a starting deviation of 20 PD or less and greater than 20 PD in the surgery group. However, in the botulinum-treated group, those patients with a starting deviation of 20 PD or less seemed to show better responses than those patients with greater than 20 PD. Patients with esotropia showed an 88.89% change with surgery and a 51.55% change with toxin treatment. Patients with exotropia had a 95.83% change with surgery but a 50.3% change with toxin treatment. Since we had 20 patients with exotropia and 10 patients with esotropia, a more formal comparison would require larger numbers.

Adolescent↗

PubMed1990

Infestation of extraocular muscle by Cysticercus cellulosae.

Reports of orbital cysticercosis are uncommon despite the high incidence of brain and ocular involvement. Infestation of extraocular muscle is exceedingly rare. Two cases of cysticercosis of the extraocular muscles are reported here. Surgical removal of the encysted parasites successfully resolved the infestation in both cases.

Adult↗

PubMed1989

The development of a water rescue unit in an urban EMS system.

A river rescue unit was developed in Pittsburgh in March 1986. From its time of inception through December 31, 1987, the unit responded 572 times (325 times in 1987); this included 144 medical calls. Many of the other calls were police related, false alarms, routine patrols, or public service calls. We present a description of the service, type of training necessary, costs involved, and administrative aspects of running a marine emergency medical services system and its integration into an urban EMS system.

Costs and Cost Analysis↗