Biomedical subjects

D Taverner

Publications and source records attributed to D Taverner.

At least 19 recordsLinked to original sources

PubMed2004

Nasal decongestants for the common cold.

BACKGROUND: The common cold is a major and recurrent cause of morbidity, affecting children and adults two or more times each year. Nasal congestion is its commonest symptom and many therapies are marketed for its relief. There is no meta-analysis of controlled clinical trials on the effects of nasal decongestants in the common cold. OBJECTIVES: To assess the efficacy of nasal decongestants at reducing the symptom of nasal congestion in adults and children with the common cold and to identify possible adverse effects associated with their use. SEARCH STRATEGY: In updating this review in 2004, the following databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2004) which contains the Cochrane Acute Respiratory Infections Group's specialised register; MEDLINE (January 1996 to February week 1 2004); EMBASE (1996 to February week 7 2004); and Current Contents (February 2004). We handsearched review citations from other references and contacted known principal investigators and pharmaceutical companies. SELECTION CRITERIA: Randomised controlled trials with placebo of single-active oral and topical nasal decongestants in adults and children suffering from common cold. DATA COLLECTION AND ANALYSIS: Data were independently extracted by two reviewers (DT and GJL). All outcomes variables were continuous. Subjective outcomes were normalised to a common scale and a weighted mean difference (WMD) was calculated. We calculated a standardised mean difference (SMD) for the objective outcomes. MAIN RESULTS: Five studies involving 286 adults were included, none in children. There was a significant 13% decrease in subjective symptoms after decongestants were compared with placebo. This was supported by a significant decrease in nasal airways resistance. Repeated doses of nasal decongestant were not significantly better than placebo at relieving symptoms of nasal congestion. REVIEWERS' CONCLUSIONS: A single dose of nasal decongestant in the common cold is moderately effective for the short term relief of congestion in adults, while there is no evidence available to show benefit after repeated use over several days. There is insufficient data on the use of these medications in children and therefore they are not recommended for use in young children with the common cold.

Adult↗

PubMed2000

Nasal decongestants for the common cold.

BACKGROUND: The common cold is a major and recurrent cause of morbidity, affecting children and adults two or more times each year. Nasal congestion is its commonest symptom, and many therapies are marketed for its relief. There is no meta-analysis of controlled clinical trials on the effects of nasal decongestants for the common cold. OBJECTIVES: To assess the efficacy of nasal decongestants at reducing the symptom of nasal congestion in adults and children with the common cold and to identify possible adverse effects associated with their use. SEARCH STRATEGY: MEDLINE, EMBASE and Current Contents were searched up to May 1999. Searching the Cochrane Acute Respiratory Infections Group's trials register, following the review citation trail from other references and contacting known principal investigators and pharmaceutical companies was also done. SELECTION CRITERIA: Randomised, placebo controlled trials of single-active oral and topical nasal decongestants in adults and children suffering from the common cold. DATA COLLECTION AND ANALYSIS: Data were independently extracted by two reviewers (DT and LB). All outcomes variables were continuous. Subjective outcomes were normalised to a common scale and a weighted mean difference (WMD) was calculated. A standardised mean difference (SMD) was calculated for the objective outcomes. MAIN RESULTS: Four studies in adults, but none in children, fitted all inclusion criteria. There was a significant 13% decrease in subjective symptoms after decongestant compared with placebo. This was supported by a significant decrease in nasal airways resistance. Repeated doses of nasal decongestant were not significantly better than placebo at relieving symptoms of nasal congestion. REVIEWER'S CONCLUSIONS: A single dose of nasal decongestant in the common cold is moderately effective for the short term relief of congestion in adults, while there is no evidence available to show benefit after repeated use over several days. These medications are not recommended for use in young children with the common cold.

Adult↗

PubMed2000

Comparison of methods for teaching clinical skills in assessing and managing drug-seeking patients.

AIMS: New medical graduates lack clinical skills in assessing and managing patients seeking drugs of dependence. This study compares the effectiveness of three different clinical skills training methods, with similar content, which were developed to teach these skills to senior medical students. METHODS: A preliminary survey indicated that common problems seen by primary care practitioners included both new and previously known patients seeking either benzodiazepines or opiates. The common content of the teaching was determined from this survey. A didactic small group tutorial (DT), a video-based tutorial (VBT) using professional actors, and a computer-aided instruction package using digitized video (CAI) were developed with this common content, and trialled with undergraduate medical students over 2 years in a parallel-group design. Outcome was assessed by student feedback, performance on a case-based written examination and by a structured evaluation of interviews with simulated patients requesting drugs. Comparison was also made between methods on the basis of knowledge tests. RESULTS: No difference was seen in written examination and simulated patient outcomes between the three groups. However, the VBT was thought by the students to be preferable to other methods. The estimated development costs of CAI were higher, but total costs over a 6-year period were lower than for the DT and VBT. The results suggest that clinical skills can be taught equally effectively through several different methods. Collaboration between institutions in the development of widely applicable CAI tools should be an efficient and economical mode of teaching with a wide range of applications.

Clinical Competence↗

PubMed1999

Evaluation of the dose-response relationship for intra-nasal oxymetazoline hydrochloride in normal adults.

OBJECTIVES: To evaluate the dose-response relationship of increasing doses of oxymetazoline compared with placebo in normal subjects, and to determine the sensitivities of rhinomanometry, acoustic rhinometry and symptoms in discriminating between differing doses of oxymetazoline in normal subjects. METHODS: The study had a randomized, double-blind, placebo-controlled, parallel group, dose-response design. One hundred and twenty-five healthy volunteers with no nasal obstruction were randomized to administration of a single intra-nasal dose of oxymetazoline (6.25 microg, 12.5 microg, 25 microg or 50 microg) or placebo to each nasal cavity. Nasal airway resistance (NAR) was measured by active posterior rhinomanometry. Total minimum cross-sectional area (tMCA) and volume (tVOL) were measured by acoustic rhinometry. Symptoms of congestion (CON) were assessed on a visual analogue scale. RESULTS: The two highest doses of oxymetazoline produced a significant decrease in NAR compared with placebo (P = 0.015) but not between placebo and 12.5 microg or 6.25 microg. There was a dose-response relationship for tVOL, which increased significantly after all doses compared with placebo (P < 0. 001) and showed differences between 6.25-microg and 25-microg (P < 0. 014) and 12.5-microg and 50-microg (P < 0.05) doses. tMCA increased compared with placebo after all treatments (P = 0.028), but there were no significant differences between any of the active doses. There were no significant changes in CON after any treatments compared with placebo. CONCLUSIONS: tVOL shows a clear dose-response relationship for the range of doses of oxymetazoline administered. tVOL provides a sensitive and discriminatory measure of small nasal changes after low doses of oxymetazoline. NAR is able to discriminate between doses, but is less sensitive than tVOL and tMCA, requiring a higher threshold dose before significant changes are seen in nasal patency.

Administration, Intranasal↗

PubMed1999

The nasal airways response in normal subjects to oxymetazoline spray: randomized double-blind placebo-controlled trial.

AIMS: The effects of a single dose of oxymetazoline nasal spray on nasal patency have been compared with placebo using three separate measuring systems in normal subjects. METHODS: The study was a placebo-controlled, randomised double-blind crossover trial. Subjects without ear, nose or throat disease and with resting nasal airways resistance >0.15 Pa s cm-3 were selected so that a fall in airways resistance could be detected. Nasal airways resistance (NAR) was measured by NR6-2 rhinomanometer. Acoustic rhinometry (SR-2000 rhinometer) provided the sum of the minimum cross-sectional areas (tMCA) and volume (tVOL) of the left and right nasal cavities. Symptoms of congestion were assessed on a visual analogue scale (CON, range 0-100). Measurements were made for 60 min before and for 120 min after bilateral administration of oxymetazoline nasal spray (0.9 mg) or placebo (0.9% saline). Crossover occurred 7-21 days later. Results for all measures were analysed as change from average baseline value by trapezoidal AUC, and statistical significance was tested by 2-way anova. RESULTS: NAR, tMCA, tVOL and CON did not change after placebo, but NAR and CON fell and tMCA and tVOL increased significantly at all timepoints after oxymetazoline. NAR_AUC, tVOL_AUC, tMCA_AUC were significantly different between placebo and oxymetazoline (P<0.001) as was CON_AUC (P=0.012). The day-to-day intraindividual repeatability of baseline NAR tMCA and tVOL was <10%. CONCLUSIONS: Normal subjects can be used to detect the effects of nasally vasoactive drugs with a variety of complementary systems, with the advantages of easy subject recruitment and low variability.

Adult↗

PubMed1999

The effects of oral pseudoephedrine on nasal patency in the common cold: a double-blind single-dose placebo-controlled trial.

A placebo-controlled double-blind randomized trial was carried out to assess the efficacy of pseudoephedrine in relieving nasal congestion in the common cold. Fifty-four previously healthy persons who had a common cold for at least 5 days or less at the start of the study with moderate to severe nasal congestion were recruited, 52 completed the trial. Following a single dose of oral pseudoephedrine (60 mg capsule) or placebo, symptoms of congestion improved significantly compared with placebo at times 60, 90, 120, and 150 min after the dose. Total nasal minimum cross-sectional area and nasal volume measured by acoustic rhinometry increased significantly compared to placebo (P = 0.018 and P = 0.003, respectively) after the dose. There was no significant change in nasal area as measured by active posterior rhinomanometry after pseudoephedrine compared to placebo. We conclude that in the acute common cold, a single 60 mg dose of pseudoephedrine produces significant increases in the dimensions of the nasal cavity compared to placebo and this is associated with a reduction in the symptom of congestion.

Acoustics↗

PubMed1999

Cross-over comparison of nifedipine Oros and felodipine extended release with blind 24 h ambulatory blood pressure assessments.

1. The aim of the present study was to compare the efficacy of nifedipine Oros and felodipine extended release (ER) in controlling 24 h ambulatory blood pressures (ABP) in hypertensive patients. 2. The study was a randomized cross-over design with a 2 week open placebo run-in phase and two observer-blind treatment periods. 3. Subjects were males and females, aged between 18 and 65 years, suffering from mild to moderate essential hypertension with a sitting mean diastolic blood pressure (DBP) within the range of 95-114 mmHg. Twenty-three subjects were randomized to treatment; 15 patients completed the study. 4. Treatment intervention was 2 weeks of placebo followed by either 30 mg nifedipine OROS once daily or 5 mg felodipine ER once daily for 6 weeks, which was titrated up to 60 mg nifedipine OROS daily or 10 mg felodipine ER daily after 2 weeks of treatment on the lower doses if the DBP was > 90 mmHg. The main outcome measure was 24 h ABP after 6 weeks of active treatment, evaluated by an independent observer blinded as to treatment allocation. 5. Compared with placebo, mean (+/- SD) 24 h DBP was reduced by 6.2 +/- 6.8 and 5.2 +/- 5.1 mmHg after nifedipine and felodipine, respectively. The 24 h mean systolic blood pressure (SBP) fell by 11.8 +/- 10.9 and 10.1 +/- 8.2 mmHg for nifedipine and felodipine, respectively, compared with placebo. There were no significant differences between the two active treatments in the reduction of DBP or SBP during the 24 h period, daytime or night-time. 6. Similar antihypertensive effects are achieved with nifedipine Oros and felodipine ER when doses are individually titrated, with no significant differences between the two treatments.

Adolescent↗

PubMed1997

Classification of heart rate variability in patients with mild hypertension.

The diagnostic performance of two pattern classification methods to detect hypertension was evaluated in a population of 29 mildly hypertensive and 20 normal subjects. The heart rate variability (HRV) signal of each subject was recorded during rest and isometric handgrip exercise. Feature vectors composed of up to 6 features from both the time and frequency domain representation of the HRV signal were constructed and applied to a Bayes' likelihood classifier and a voting k-nearest neighbours classifier. Each subject was classified as hypertensive or normal, and the classification compared to the clinical diagnosis for each subject. The diagnostic performance of each classifier/feature vector combination was evaluated using the leave-one-out method. The best performance of 90% correct classifications was achieved using a nearest neighbour classifier, a Euclidean distance metric and 3 features. The Bayes' classifier achieved a best performance of 84% correct classification. The work shows promise for the detection of the autonomic disturbance which precedes and accompanies the hypertensive state.

Analysis of Variance↗

PubMed1996

Reproducibility of conventional and power spectral measurements of cardiovascular sympathetic activation in normal subjects.

1. Normal subjects (n = 5; age 20-42 years; mean resting blood pressure (+/- 1 s.d.) 116 +/- 21/61 +/- 11 mmHg) underwent cardiovascular reflex testing five times each. On every occasion systolic blood pressure (SBP) responses to sustained handgrip (GRIP) and cold pressor (COLD) tests were measured and continuous non-invasive SBP and heart period (RRINT) data were analysed in the frequency domain using fast Fourier transforms. Power spectral (PS) density estimates of high frequency/total power (HF%; a measured of vagal activity), low frequency/HF ratio (LF/HF; a measure mainly of cardiovascular sympathetic activity for heart period) and low frequency/total power (LF%; a proposed measure of sympathetic activity for SBP) at rest, during and 2 min after the end of stimuli were calculated. 2. The data from the rest and recovery periods did not differ and showed that cardiovascular recovery to baseline measures following sympathetic stimulation occurred within 2 min. 3. There was a significant rise in SBP with GRIP and COLD. The LF/HF(RRINT) rose significantly with GRIP, but not with COLD. The LF%(SBP) did not change significantly with GRIP or COLD. 4. The SBP and PS analyses showed low intra-individual reproducibility of responses to reflex tests, with coefficients of variation for PS measures at rest of 25-41% and on sympathetic stimulation of up to 80%. 5. The high variability of these observations indicates that PS methods may not be suitable for the analysis of transient cardiovascular reflexes.

Adult↗

PubMed1991

The effects of selective beta-adrenoceptor antagonists and partial agonist activity on renal function during exercise in normal subjects and those with moderate renal impairment.

1. The effects of sustained moderate exercise in the sitting position on renal haemodynamics and glomerular filtration were measured in six normotensive patients with moderately impaired renal function and seven age-matched normal volunteers. 2. The changes in the effects of exercise on renal function induced by chronic cardioselective beta-adrenoceptor blockade by drugs with (epanolol) and without intrinsic sympathomimetic activity (atenolol) were examined. 3. Both beta-adrenoceptor blockers attenuated the heart rate increase with exercise, but only atenolol lowered blood pressure significantly. In resting volunteers on atenolol, associated with the fall in blood pressure there was a significant reduction in glomerular filtration rate. 4. Glomerular filtration fell significantly in all groups with exercise, and renal blood flow also fell in parallel. These changes were not influenced by drug treatment. 5. The exercise-induced rise in PRA was suppressed by atenolol but not by epanolol. 6. The renal function and haemodynamic responses to moderate exercise does not appear to be mediated by the systemic renin-angiotensin system or by beta 1-adrenoceptors.

Adrenergic beta-Agonists↗

PubMed1991

Effects of exercise on renal function in patients with moderate impairment of renal function compared to normal men.

The renal excretory and haemodynamic responses to sustained moderate exertion were investigated in normotensive humans with impaired renal function and normal volunteers. The heart rate increase with exercise was similar in each group. Subjects with impaired renal function showed a significant fall in glomerular filtration rate on exertion, while normals did not. In the presence of renal disease, urine osmolality did not rise with exertion, although it rose markedly in the normal group. Free water clearance became negative after exercise in the normal group only. The diseased kidney is unable to maintain glomerular filtration rate or conserve water under the stress of exertion as well as the normal kidney.

Adult↗

PubMed1989

Acute and chronic arterial and venous effects of captopril in congestive cardiac failure.

OBJECTIVE: To determine whether captopril alters peripheral venous tone in patients with congestive cardiac failure. DESIGN: Open study of patients at start of captopril treatment and three months later. SETTING: A hospital gamma camera laboratory. PATIENTS: 16 Men with congestive cardiac failure in New York Heart Association class II or III, aged 57-73. INTERVENTIONS: Patients were initially given 500 micrograms sublingual glyceryl trinitrate followed by 25 mg oral captopril. The study was then repeated after three months' captopril treatment. MAIN OUTCOME MEASURES: Previously validated non-invasive radionuclide techniques were used to measure changes in central haemodynamic variables and peripheral venous volumes in the calf. RESULTS: After 25 mg captopril there were falls in blood pressure and relative systemic vascular resistance and increases in cardiac index and left ventricular ejection fraction. This was accompanied by a 16% increase in peripheral venous volume (95% confidence interval 13.4% to 18.4%, p less than 0.01), which compared with an 11% increase after 500 micrograms glyceryl trinitrate (10% to 12%, p less than 0.01). Eleven patients were restudied after three months' continuous treatment with captopril. The resting venous volume was higher than it had been initially, by about 10%, and increased by a further 8.4% after 25 mg captopril (5.4% to 11.4%, p less than 0.05). CONCLUSIONS: Captopril is an important venodilator. Venous and arterial dilatation are produced short term and during long term treatment.

Aged↗

PubMed1988

Acute renal failure due to interstitial nephritis induced by 'glue-sniffing' with subsequent recovery.

We report a case of the deliberate inhalation of a toluene-containing adhesive which caused acute renal failure and hepatic damage. Renal biopsy disclosed a severe tubulo-interstitial nephritis, renal function recovered after 14 days' haemodialysis. The literature on renal complications of toluene exposure is reviewed, this is the only case of acute renal failure due to interstitial nephritis after toluene exposure with subsequent recovery. Recovery in this case may have been related to the avoidance of further toluene exposure.

Acute Kidney Injury↗

PubMed1986

Vasodepressor mechanisms in experimental hypertension: studies using chemical medullectomy.

There is evidence that neither activation of the renin-angiotensin system nor changes in sodium balance can fully explain the maintenance of blood pressure in Goldblatt hypertension. Thus, in Goldblatt two-kidney, one clip hypertension in the rat sodium balance is negative and in hypertension of a few months' duration plasma renin initially elevated has returned to normal. When hypertension is reversed by removal of the constricting clip from the renal artery, blood pressure falls within a matter of hours even when hypertension has been present for many months, suggesting that the effect of structural changes in vascular resistance vessels has been overcome. In addition, blockade of the renin-angiotensin system during renal artery declipping does not influence the pattern of the blood pressure fall. We investigated the role of the renomedullary vasodepressor system by inducing medullary necrosis with 2-bromo-ethylamine hydrobromide. This causes a moderate blood pressure increase in normal rats, and partly inhibits the fall of blood pressure in Goldblatt two-kidney, one clip hypertension when the renal clip is removed. Chemical medullectomy is associated with a slightly negative sodium balance, plasma volume contraction, a reduction in plasma renin activity and urinary PGE2, and a minimal elevation in plasma vasopressin. Blood pressure elevation appears to be attributable to inhibition of a vasodepressor system based on the renal medulla. Chemical medullectomy offers a valuable tool for investigating the role of this medullary vasodepressor system.

Animals↗

PubMed1985

Fluid volumes and hemodynamics in hypertension produced by chemical renal medullectomy.

We have investigated the mechanisms by which chemical renal medullectomy with 2-bromoethylamine hydrobromide (200 mg/kg body wt) produces hypertension in rats. Groups of chemically medullectomized rats were compared with normal rats and rats that had been partially nephrectomized to produce an equivalent fall in glomerular filtration rate. Mean arterial pressure was elevated in the medullectomized (142 +/- 6 mmHg) compared with normal rats (124 +/- 3). In the medullectomized animals this was associated with significant tachycardia (483 +/- 15 vs. 450 +/- 6 beats/min) and an increase in cardiac output (61.1 +/- 5.0 vs. 49.9 +/- 2.2 ml X min-1 X 100 g body wt-1). Plasma volume was significantly reduced in medullectomized rats (2.16 +/- 0.15 vs 3.29 +/- 0.20 ml/100 g body wt), whereas exchangeable sodium was unchanged (39.9 +/- 0.5 vs. 39.7 +/- 0.5 meq/kg body wt). By contrast, both plasma volume and exchangeable sodium were increased in partially nephrectomized rats. These results are consistent with the hypothesis that chemical medullectomy produces hypertension by increased selective sympathetic efferent activity, raising cardiac output and postcapillary venular resistance. This may be the consequence of reducing the secretion of a renomedullary humoral substance that normally inhibits such activity.

Animals↗

PubMed1984

Effect of unclipping on pressor responses in rats with renovascular hypertension.

Pressor responses to angiotensin II and noradrenaline have been examined in two models of renovascular hypertension (two-kidney one-clip and one-kidney one-clip) before and 24 h after removal of the renal artery clip to examine the possible role of pressor hyper-responsiveness in the maintenance of hypertension. Early and chronic hypertension was studied to assess the part played by progressive structural hypertrophy. Plasma renin concentration was elevated in early two-kidney hypertensive rats, whereas it was similar to that in age-matched normal rats in early one-kidney and chronic two-kidney hypertensive rats. Twenty-four hours after unclipping plasma renin concentration was the same in all groups. Unclipping restored blood pressure to normal levels by 24 h, whereas sham-operated animals remained hypertensive. Angiotensin II responses in both early and chronic two-kidney one-clip hypertensive rats were lower than in age-matched normal rats. In unclipped rats responses were similar to those in normals. One-kidney hypertensive rats had similar angiotensin II responses to normal rats and there was no change with unclipping. Blockade of endogenous angiotensin II production by converting enzyme inhibition resulted in similar angiotensin II responses in hypertensive and unclipped groups. In normal rats, angiotensin II responses were inversely related to plasma renin concentration (r = -0.47, P less than 0.001). Angiotensin II responses in hypertensive and unclipped rats were found to show a similar relationship to plasma renin concentration as normal rats. Noradrenaline responses in hypertensive rats were similar to those in age-matched normals and there was no significant change with unclipping.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗

PubMed1984

Hypertension produced by chemical renal medullectomy: evidence for a renomedullary vasodepressor function in the rat.

The rat renal papilla was selectively destroyed by 2-bromoethylamine hydrobromide; increasing doses produced a graded severity of histological damage, polyuria and a reduction in urinary prostaglandin E2 excretion. Destruction of at least half of the papilla caused significant hypertension, but plasma renin concentration and plasma creatinine did not change. After graded medullary damage Goldblatt two-kidney, one-clip hypertension was induced. Four weeks later the severity of hypertension was similar in medulla-damaged and medulla-intact groups. When Goldblatt two-kidney, one-clip hypertension was reversed by removal of the renal artery clip, the blood pressure fall was less when the inner renal papilla was ablated than when it was intact, although plasma renin concentration and sodium balance were similar. The final blood pressure was similar to that observed in normal rats treated with 2-bromoethylamine compared with their respective controls. These findings are consistent with the hypothesis that the inner renal medulla produces a vasodepressor that influences blood pressure in normal rats, and also lowers blood pressure when two-kidney, one-clip hypertension is reversed surgically.

Animals↗

PubMed1984

Cimetidine therapy does not prevent rebleeding from peptic ulceration.

One-hundred and five patients admitted to hospital with symptoms of acute upper gastrointestinal haemorrhage shown at endoscopy to be due to peptic ulceration were entered into a prospective double-blind controlled trial of cimetidine versus placebo therapy. The trial therapy was commenced within 12 hr of admission and continued for 7 days. Cimetidine therapy made no difference to the transfusion requirements, rebleeding rate or number of operations performed in patients with either gastric or duodenal ulcers, nor was it of benefit in patients aged over 65 years of age.

Aged↗