PubMed Health⌕ Search

Biomedical subjects

W Elliott

Publications and source records attributed to W Elliott.

At least 19 recordsLinked to original sources
PubMed1999

Substrate utilization during submaximal exercise in obese and normal-weight women.

In this study we compared substrate use at submaximal intensities of a maximal graded exercise test (GXT) with that derived from equivalent intensities during continuous submaximal steady-state exercise in obese and normal-weight women. Sedentary obese (n = 20, body fat > 30%) and normal-weight (n = 15, body fat < or =30%) women performed three treadmill tests with concurrent metabolic measurements. Maximal oxygen consumption (VO2max) was determined using the Bruce protocol, followed by two, randomly assigned, continuous 15-min, steady-state exercise bouts, on different days; one bout at 50% and one bout at 75% VO2max. Analysis of variance revealed no significant differences between groups for blood lactate or respiratory exchange ratio (R) values at any point during exercise. Therefore, obese and normal-weight group data were combined for subsequent analyses. The R at 50% VO2max from the GXT [0.83 (0.01)] was significantly (P < 0.05) lower than at 8 min [0.90 (0.01)] and 15 min [0.89 (0.01)] of steady-state exercise, whereas at 75% VO2max, the GXT R [0.96 (0.01)] was similar to that seen at 8 min [0.96 (0.01)] and at 15 min of steady-state exercise [0.93 (0.01)]. Blood lactate values at 50% VO2max were similar between the GXT [1.66 (0.10) mM] and steady-state exercise [1.65 (0.09) mM], but at 75% VO2max the GXT blood lactate values [2.58 (0.21) mM] were lower than after 15 min of steady-state exercise [4.65 (0.46) mM]. Total exercise fat oxidation was greater at 50% compared to 75% VO2max. There was no difference in substrate use between sedentary obese and normal-weight women either at rest or during steady-state exercise at the same relative intensity. Total fat oxidation was greater during low- (50% VO2max) compared to high-intensity (75% VO2max) exercise. Data from a GXT cannot be used to predict R or substrate utilization values for the purpose of exercise prescription.

Adolescent↗
PubMed1998

Comparative efficacy of two angiotensin II receptor antagonists, irbesartan and losartan in mild-to-moderate hypertension. Irbesartan/Losartan Study Investigators.

The primary objectives of this double-blind study were to compare the antihypertensive efficacy and tolerability of irbesartan and losartan, two angiotensin II (AT1 subtype) receptor antagonists with different pharmacokinetic profiles in patients with mild-to-moderate hypertension. Both drugs are approved for once-daily use (although losartan may also be prescribed twice-daily). After a placebo lead-in, 567 patients were randomized (1:1:1:1) to once-daily therapy with placebo, 100 mg losartan, 150 mg irbesartan, or 300 mg irbesartan for 8 weeks. Treatment groups had comparable demographic and baseline characteristics. After 8 weeks of treatment, reductions from baseline in trough seated diastolic blood pressure (SeDBP) and trough seated systolic blood pressure (SeSBP) with 300 mg irbesartan were greater than with 100 mg losartan (P < .01 for both comparisons), by 3.0 and 5.1 mm Hg, respectively; larger reductions were also demonstrated at weeks 1 and 4 (P < .01 and P = .017, respectively, for SeDBP). Throughout the study, the antihypertensive effect of 150 mg irbesartan did not differ significantly from that of 100 mg losartan. All therapies were well tolerated. The 300 mg dose of irbesartan was associated with the lowest incidence of adverse events (AE) and discontinuations because of AE. This study demonstrates that the maximally effective once-daily doses of two different AT1 receptor antagonists may result in clinically significant differences in blood pressure reductions, and therefore highlights the potential importance of the pharmacokinetic and pharmacodynamic differences between these two members of this class.

Adolescent↗
PubMed1997

If it's not there, where is it? Locating illusory conjunctions.

There is evidence that complex objects are decomposed by the visual system into features, such as shape and color. Consistent with this theory is the phenomenon of illusory conjunctions, which occur when features are incorrectly combined to form an illusory object. We analyzed the perceived location of illusory conjunctions to study the roles of color and shape in the location of visual objects. In Experiments 1 and 2, participants located illusory conjunctions about halfway between the veridical locations of the component features. Experiment 3 showed that the distribution of perceived locations was not the mixture of two distributions centered at the 2 feature locations. Experiment 4 replicated these results with an identification task rather than a detection task. We concluded that the locations of illusory conjunctions were not arbitrary but were determined by both constituent shape and color.

Color Perception↗
PubMed1995

A Cryptosporidium parvum genomic region encoding hemolytic activity.

Successful parasitization by Cryptosporidium parvum requires multiple disruptions in both host and protozoan cell membranes as cryptosporidial sporozoites invade intestinal epithelial cells and subsequently develop into asexual and sexual life stages. To identify cryptosporidial proteins which may play a role in these membrane alterations, hemolytic activity was used as a marker to screen a C. parvum genomic expression library. A stable hemolytic clone (H4) containing a 5.5-kb cryptosporidial genomic fragment was identified. The hemolytic activity encoded on H4 was mapped to a 1-kb region that contained a complete 690-bp open reading frame (hemA) ending in a common stop codon. A 21-kDa plasmid-encoded recombinant protein was expressed in maxicells containing H4. Subclones of H4 which contained only a portion of hemA did not induce hemolysis on blood agar or promote expression of the recombinant protein in maxicells. Reverse transcriptase-mediated PCR analysis of total RNA isolated from excysted sporozoites and the intestines of infected adult mice with severe combined immunodeficiency demonstrated that hemA is actively transcribed during the cryptosporidial life cycle.

Amino Acid Sequence↗
PubMed1992

Endotracheal tube safety during electrodissection tonsillectomy.

A case report of an endotracheal tube fire occurring during electrodissection tonsillectomy is presented. The authors believe that this incident occurred because a retrograde leak of ventilating gases around an uncuffed endotracheal tube during positive-pressure ventilation produced a high oxygen concentration in the mouth, allowing indirect ignition of the tube. In vitro testing supported this hypothesis. Ignition tests on polyvinylchloride endotracheal tubes using electrocautery in various oxygen concentrations were performed. As oxygen concentration increased, the endotracheal tube could be moved further from the cautery and still allow ignition of the tube. At 52% oxygen, with the cautery set at 25-W coagulation current, the endotracheal tube could not be ignited. Recommendations to prevent a recurrence of this incident are included.

Child↗
PubMed1992

Dual function nitroimidazoles less toxic than RSU 1069: selection of candidate drugs for clinical trial (RB 6145 and/or PD 130908.

Following the toxicity and synthetic difficulties encountered with the hypoxic cell radiosensitizer RSU 1069, efforts have focused on development of a superior analogue. Two compounds, RB 6145 and PD 130908, have emerged from this program which overcome the instability and synthetic problems associated with RSU 1069 while retaining favorable biological activity. Both agents show comparable radiosensitizing activity to RSU 1069 following oral or i.p. administration to mice bearing the KHT or RIF-1 tumors. Sensitizing efficiency is about 10 X greater than that observed for misonidazole or etanidazole. Toxicity toward hypoxic tumor cells in vivo is demonstrated by clamping tumors (for 60 min) following administration of PD 130908 or RB 6145. Both are effective hypoxic cytotoxins, but less potent than RSU 1069. Systemic toxicity is substantially reduced following oral drug administration. Further, doses achievable following fractionated drug treatments are sufficiently high to produce significant levels of radiosensitization.

Animals↗
PubMed1992

The influence of changing age and referral for end-stage renal failure in Newcastle upon Tyne.

This paper reports a retrospective analysis of renal replacement therapy in patients over 60 years-of-age admitted to regional unit in Newcastle upon Tyne during a 7-year period. The changing age patterns of referral for management of end-stage renal failure have been reviewed, including the morbidity and mortality of this age-group managed for end-stage renal failure by haemodialysis, peritoneal dialysis and transplantation. The results show an alarming increase in the number of referrals aged over 60 years (> 36% in 4 years). Associated medical problems, methods of treatment and management (including special needs), and the effects of the rapidly increasing proportion of elderly patients on renal services are described.

Aged↗
PubMed1990

Ketoconazole reduces elevated serum levels of 1,25-dihydroxyvitamin D in hypercalcemic sarcoidosis.

The antifungal drug ketoconazole, a cytochrome P450 inhibitor, has been shown to inhibit renal 1,25-dihydroxyvitamin D production in vitro and to lower serum 1,25-dihydroxyvitamin D levels in normal subjects and in patients with primary hyperparathyroidism. To assess the usefulness of this drug in the hypercalcemia of sarcoidosis, a condition thought to result from overproduction of 1,25-dihydroxyvitamin D by sarcoid-involved tissues, two men with sarcoidosis, hypercalcemia, and elevated serum levels of 1,25-dihydroxy-vitamin D were given ketoconazole, 600-800 mg per day, for four to six days. Serum 1,25-dihydroxyvitamin D levels were markedly reduced (by approximately 40%) in both patients during ketoconazole administration, but serum calcium was not affected. In both patients, renal function deteriorated during ketoconazole treatment. We conclude that ketoconazole administration can lower the elevated serum 1,25-dihydroxyvitamin D levels in sarcoidosis. However, deterioration of renal function during ketoconazole administration as well as failure of hypercalcemia to be affected during short-term ketoconazole treatment suggest that this drug might not be appropriate for acute treatment of hypercalcemic sarcoidosis.

Adult↗
PubMed1987

Recovery from early cortical damage in rats. II. Effects of experience on anatomy and behavior following frontal lesions at 1 or 5 days of age.

Perinatal cortical damage is often associated with significant overall shrinkage of the remaining cortex and severe behavioral impairments. Environmental experience was manipulated in order to determine if the anatomical and behavioral effects of neonatal frontal decortication might be attenuated by rearing in a complex environment. Rats received frontal decortication on the day of birth or 5 days later and were subsequently raised, along with littermate controls, in a complex environment or in standard laboratory cages. In adulthood, the animals were tested on a battery of behavioral tests which showed that enrichment markedly attenuated the effects of the early lesions, especially for the 5-day operates, even on tests such as tongue extension that would not be expected to benefit from specific practice in the complex environment. Analysis of the remaining cortex revealed that all groups raised in the complex environment developed thicker cortex, the increase being most dramatic in the rats given lesions at 5 days of age.

Animals↗
PubMed1986

Charcoal hemoperfusion for the treatment of a combined diltiazem and metoprolol overdose.

We describe the management of a 49-year-old woman who ingested 1,200 mg diltiazem and 500 mg metoprolol. The patient was bradycardic and hypertensive, requiring large doses of inotropic agents and temporary transvenous pacing. Charcoal hemoperfusion was used as an adjunct technique to hasten drug elimination; it rapidly lowered plasma drug levels, with a parallel improvement in the patient's clinical condition.

Charcoal↗
PubMed1985

Continuous ambulatory peritoneal dialysis and renal transplantation: a five year experience.

Continuous ambulatory peritoneal dialysis is a new and increasingly popular method of routine dialysis, but its effect on renal transplantation is uncertain. A non-randomised comparison was made of the outcome of grafting in patients who had been treated before transplantation with continuous ambulatory peritoneal dialysis with that in patients treated with haemodialysis. During the five years, 1979-84, after continuous ambulatory peritoneal dialysis was introduced to Newcastle upon Tyne 220 patients have received transplants after either continuous ambulatory peritoneal dialysis (61 patients) or haemodialysis (159 patients). During follow up no significant differences occurred in survival of patients or grafts between the two treatment groups. One year after transplantation the percentages of survivors who had received continuous ambulatory peritoneal dialysis and haemodialysis were 88% and 91% respectively, and overall graft survival was 66% and 72%, respectively. A multiple regression model was used to allow for differences among patients--for example, duration of dialysis and number of preoperative transfusions--on the survival of grafts. When only first cadaver grafts were considered (in 152 patients) graft survival (non-immunological failures excluded) was not significantly different between the patients treated with continuous ambulatory peritoneal dialysis and haemodialysis. Continuous ambulatory peritoneal dialysis is not a risk factor in renal transplantation, and its continued use in treatment of potential renal graft recipients is recommended.

Adolescent↗
PubMed1982

Comparison of the allergenicity and antigenicity of yellow jacket and hornet venoms.

The immunologic properties of yellow jacket and hornet venoms were compared by measuring their reaction with rabbit antisera and human IgE and IgG antibodies. Anti-hornet venom rabbit serum showed precipitin bands unique to hornet venom and several bands crossreacting with yellow jacket venom. Anti-yellow jacket venom rabbit serum reacted with yellow jacket venom but failed to react with the hornet venoms. Most sera from patients who had had allergic reactions after vespid stings reacted with yellow jacket and hornet venoms in RAST analysis. A few sera reacted with only one of the venoms. RAST inhibition studies confirmed the crossreactivity of these IgE antibodies. The IgG antibody response of 14 patients was measured after yellow jacket venom immunotherapy. All had rising titers of yellow jacket venom-specific IgG. There was also an increase in the IgG antibody response measured with hornet venom in the majority of patients. The rise was significant with yellow hornet venom (p less than 0.02) but failed to reach significance with bald-faced hornet venom (p greater than 0.05). In IgG radioimmunoassay inhibition studies using yellow jacket venom-coupled discs, yellow jacket venom was considerably more potent than hornet venom. These studies indicate major crossreactivity between yellow jacket and hornet venoms. In this group of patients, yellow jacket venom appeared to be the primary allergen.

Allergens↗
PubMed1982

Studies of chemically modified honeybee venom. I. Biochemical, toxicologic and immunologic characterization.

Allergens of honeybee venom (BV) were modified by formaldehyde treatment (F), acetoacetylation (A) or coupling to polyethylene glycol (P). The biochemical, toxicologic and immunologic properties of these modified BV preparations were analyzed. F showed strongly reduced cytotoxicity, enzymatic activity and reactivity with human BV-specific IgE antibodies but retained the reactivity to BV-specific human and rabbit IgG. In A, enzymatic activity, cytotoxicity and the reactivity with human IgE and rabbit IgG antibodies were only moderately reduced. P lacked enzymatic activity and cytotoxicity and showed only minimal reactivity with IgE and IgG antibodies to BV.

Acetoacetates↗
PubMed1981

Comparison of vespid venoms collected by electrostimulation and by venom sac extraction.

Venoms of three vespid species, yellow jacket, bald-faced hornet, and yellow hornet, obtained by either electrostimulation of venom sac extraction were compared with regard to their enzymatic activity, antigenicity, and allergenicity. Phospholipase a, phospholipase B, and hyaluronidase enzymatic activities were present in all six preparations. The activity of venom sac extracts lay in the range found in different batches of venoms obtained by electrostimulation for each species. Analysis of sera from vespid-sensitive patients in the radioallergosorbent test (RAST) with discs coupled with either venom sac extracts or venoms obtained by electrostimulation showed a good correlation of the results within all three species (r = 0.95). In RAST inhibition the potency of venom sac extracts and venom obtained by electrostimulation was similar for each species. Analysis of rabbit antisera to the six preparations revealed similar patterns in immunoelectrophoresis and identity reactions between the major antigens within each species. Tissue protein contamination was detected in all venom sac extracts but not in venoms obtained by electrostimulation.

Animals↗
PubMed1980

Comparison of the venom immunogenicity of various species of yellow jackets (genus Vespula).

Venoms from various yellow jacket species were examined by two-dimensional thin-layer chromatography (TDTLC), double-diffusion gel precipitation (DDGP) using rabbit antisera, and the radioallergosorbent test (RAST). Comparison of representative venoms by the TDTLC showed that the venoms of V. vulgaris and V. maculifrons have a larger number of Ninhydrin (triketohydrindene hydrate)-positive substances than the venom of V. squamosa. The results of the DDGP confirmed the differences; venoms of V. vulgaris, V. maculifrons, V. flavopilosa, and V. germanica have one or more major components with immunogenic identity. The venom of V. squamosa has a species-specific major component and some minor components immunologically identical to the other venoms examined. Sera from 21 patients with a history of anaphylaxis following yellow jacket stings were examined by the RAST. Using the venoms of V. maculifrons, V. vulgaris, V. flavopilosa, and V. germanica as coupling antigens, most sera reacted similarly. The sera did not react with V. squamosa. These results suggest that the major component in venom obtained from the four yellow jacket species has immunogenic identity. Venom of V. squamosa differs from the remaining venoms. As a practical corollary, with the exception of venom from V. squamosa, common sensitivity appears to exist among the yellow jacket venoms examined.

Animals↗