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Biomedical subjects

Hans Hedenström

Publications and source records attributed to Hans Hedenström.

8 recordsLinked to original sources
PubMed2006

Interval training compared with continuous training in patients with COPD.

The aim of this study was to compare the effects of interval training (3-min intervals) with continuous training on peak exercise capacity (W peak), physiological response, functional capacity, dyspnoea, mental health and health-related quality of life (HRQoL) in patients with moderate or severe COPD. Sixty patients exercised twice weekly for 16 weeks after randomisation to interval- or continuous training. Target intensity was 80% of baseline W peak in the interval group (I-group) and 65% in the continuous group (C-group). Patients were tested by spirometry, ergometer cycle test, cardiopulmonary test and a 12 min walk test. Dyspnoea was measured by the dyspnoea scale from Chronic Obstructive Disease Questionnaire (CRDQ), mental health by Hospital Anxiety and Depression scale (HAD) and HRQoL by the Medical Outcomes Survey Short Form 36 (SF-36). After training, W peak, peak oxygen uptake (VO(2) peak) and exhaled carbon dioxide (VCO(2) peak) increased significantly in both groups, no significant differences between the groups. Minute ventilation (V(E) peak) increased only in the C-group. At identical work rates (isotime) VO(2), VCO(2) and V(E) were significantly more decreased in the I-group than in the C-group (p<0.05). Functional capacity, dyspnoea, mental health, and HRQoL improved significantly in both groups, no difference between the groups. Interval training and continuous training were equally potent in improving peak exercise capacity, functional exercise capacity, dyspnoea, mental health and HRQoL in patients with moderate or severe COPD. At isotime, the physiological response to training differed between the groups, in favour of the interval training.

Adult↗
PubMed2006

Peak exercise capacity estimated from incremental shuttle walking test in patients with COPD: a methodological study.

BACKGROUND: In patients with COPD, both laboratory exercise tests and field walking tests are used to assess physical performance. In laboratory tests, peak exercise capacity in watts (W peak) and/or peak oxygen uptake (VO2 peak) are assessed, whereas the performance on walking tests usually is expressed as distance walked. The aim of the study was to investigate the relationship between an incremental shuttle walking test (ISWT) and two laboratory cycle tests in order to assess whether W peak could be estimated from an ISWT. METHODS: Ninety-three patients with moderate or severe COPD performed an ISWT, an incremental cycle test (ICT) to measure W peak and a semi-steady-state cycle test with breath-by-breath gas exchange analysis (CPET) to measure VO2 peak. Routine equations for conversion between cycle tests were used to estimate W peak from measured VO2 peak (CPET). Conversion equation for estimation of W peak from ISWT was found by univariate regression. RESULTS: There was a significant correlation between W peak and distance walked on ISWT x body weight (r = 0.88, p < 0.0001). The agreement between W peak measured by ICT and estimated from ISWT was similar to the agreement between measured W peak (ICT) and W peak estimated from measured VO2 peak by CPET. CONCLUSION: Peak exercise capacity measured by an incremental cycle test could be estimated from an ISWT with similar accuracy as when estimated from peak oxygen uptake in patients with COPD.

Adult↗
PubMed2006

Improved systemic safety and risk-benefit ratio of topical 0.1% timolol hydrogel compared with 0.5% timolol aqueous solution in the treatment of glaucoma.

PURPOSE: The purpose of the study was to compare the systemic safety and risk-benefit ratio of 0.1% timolol hydrogel and 0.5% aqueous timolol eye drops in the treatment of glaucoma. METHODS: An 8-week randomised, double-blind, cross-over, multicentre study. A total of 25 patients with primary open-angle glaucoma, exfoliation glaucoma, or ocular hypertension was enrolled. After completing a wash-out period, patients were randomly chosen to receive either 0.1% timolol hydrogel once daily or 0.5% aqueous timolol eye drops twice daily. Intraocular pressure and heart rate during rest and exercise, head-up tilt test results, spirometry readings, and plasma concentrations of timolol were recorded. The risk-benefit ratio was determined by calculating the ratio between several heart rate endpoints and the change in intraocular pressure (IOP). RESULTS: The mean drug-induced change in the peak heart rate during exercise was -13.5 beats/min (SD 7.6) in the 0.5% aqueous timolol group and -5.1 beats/min (SD 6.7) in the 0.1% timolol hydrogel group (P<0.001; 95% CI 4.06-12.18). There was no significant difference in the IOP-reducing efficacy between these compounds. The risk-benefit ratio was significantly improved when 0.1% timolol hydrogel was used, compared with 0.5% aqueous timolol in the exercise test. In the head-up tilt test the risk-benefit ratio was significantly improved at rest (P<0.05), at 1 min (P<0.05) and at 5 min (P<0.001) after patients had received 0.1% timolol hydrogel. There were, however, no differences in spirometry readings. After patients had been treated with 0.1% timolol hydrogel, plasma concentrations of timolol were 1/6 (at peak) and 1/50 (at trough) of those of 0.5% aqueous timolol. CONCLUSIONS: Drug-induced changes in the peak heart rate, and head-up tilt test results as well as plasma concentrations of timolol, were significantly more pronounced after treatment with 0.5% aqueous timolol than with 0.1% timolol hydrogel. Because of the statistically similar IOP-reducing efficacy of these formulations the risk-benefit ratio was significantly improved when patients used 0.1% timolol hydrogel instead of 0.5% aqueous timolol.

Administration, Topical↗
PubMed2005

Association between low plasma levels of ophthalmic timolol and haemodynamics in glaucoma patients.

OBJECTIVES: The aims of the study were to assess the correlation between the plasma concentration of ophthalmic timolol and cardiovascular parameters, and the influence of timolol on advanced haemodynamic variables, such as stroke (SI), cardiac (CI) and systemic vascular resistance (SVRI) indices and arterial pulse wave velocity (PWV). METHODS: Twenty-five glaucoma or ocular hypertensive patients were treated with 0.5% aqueous and 0.1% hydrogel formulations of timolol using a randomised, double-masked, crossover, multicentre design. All the patients were subjected to passive head-up tilt, electrocardiography, exercise test and measurement of plasma concentration of timolol. In the analysis, the data on the two treatments were combined, and the Spearman correlation coefficients between the plasma level of timolol and physiological effects were calculated. RESULTS: During the head-up tilt test before rising the bed up, the resting heart rate (HR; R=-0.52, P=0.001) and PWV (R=-0.34, P=0.04) were inversely correlated with timolol level. In the upright position, ophthalmic timolol effectively suppressed the rise in HR (R=-0.36, P=0.03). The SI did not change with timolol concentration, while CI diminished as timolol concentration rose (R=-0.39, P=0.02). The SVRI correlated with timolol concentration (R=0.38, P=0.02). In the exercise test, correlation between HR and plasma level of timolol steadily grew stronger as the load increased, reaching R=-0.60 (P<0.0001) at the maximum load. Systolic and diastolic arterial pressures were not associated with the timolol concentration. CONCLUSION: The plasma concentration of ophthalmic timolol correlates with several haemodynamic effects. As HR decreases, SVRI increases and blood pressure is kept unchanged.

Adrenergic beta-Antagonists↗
PubMed2002

Effect of esomeprazole 40 mg vs omeprazole 40 mg on 24-hour intragastric pH in patients with symptoms of gastroesophageal reflux disease.

Maintenance of intragastric pH > 4 is vital for effective management of gastroesophageal reflux disease (GERD). Esomeprazole 40 mg, the first proton pump inhibitor developed as an optical isomer, demonstrates improved acid inhibition over omeprazole 20 mg. Our aim was to compare esomeprazole 40 mg with omeprazole 40 mg, once-daily, on intragastric acidity in patients with symptoms of GERD. In this open-label, crossover study, 130 patients with symptoms of GERD received esomeprazole 40 mg or omeprazole 40 mg once-daily for five days. The 24-hr intragastric pH was monitored on days 1 and 5 of each treatment period. The mean percentage of the 24-hr period with intragastric pH > 4 was significantly greater (P < 0.001) with esomeprazole 40 mg than with omeprazole 40 mg on days 1 (48.6% vs 40.6%) and 5 (68.4% vs 62.0%). Interpatient variability was significantly less with esomeprazole than omeprazole. Esomeprazole was well tolerated. In conclusion, esomeprazole 40 mg provides more effective acid control than twice the standard dose of omeprazole.

Adult↗
PubMed2002

Duodenogastric bile reflux after gastric bypass: a cholescintigraphic study.

In this exploratory study, we examined the occurrence of duodenogastric bile reflux to the excluded stomach after Roux-en-Y gastric bypass, a standard surgical therapy for morbid obesity. We studied 22 unselected patients (median age 44, 20 females) 18 months postoperatively. BMI at surgery and cholescintigraphy was 45 and 29 kg/m2, respectively. Mebrofenin labeled with 200 MBq 99mT was injected intravenously and the fate of radioactivity followed for 90 min. Bile flow was enhanced with cholecystokinin. We found scintigraphic evidence of duodenogastric bile reflux in 36% of the patients. The tracer remained in the excluded stomach throughout the study period. In conclusion, our investigation indicates that in more than one third of the patients undergoing gastric bypass, the gastric mucosa in the excluded stomach is exposed to the potential deleterious effects of bile.

Adolescent↗
PubMedDate not supplied

Role of gastric acid in stomal ulcer after gastric bypass.

BACKGROUND: The pathogenetic mechanisms of stomal ulcer after Roux-en-Y gastric bypass (RYGBP) are unclear. In order to study the role of gastric acid, we measured acidity in the proximal pouch using a pH-sensitive probe. METHODS: 6 patients (5 females, mean age 45 years old at time of operation) with endoscopically confirmed stomal ulcer, were studied 2 to 6 years after RYGBP. All complained of epigastric pain that improved during proton pump inhibitor (PPI) therapy. Control subjects were 6 females (50 years old) who had had RYGBP at least 5 years earlier and denied symptoms of epigastric pain or heartburn. The pH-sensitive probe (Digitrapper-pH, Medtronic) was passed through the nose to the proximal pouch, guided by the calculated distance and pH response. The probe was left in place for 4 hours. The percentage of time with pH <4 was calculated. RESULTS: The probe could be accurately positioned in the proximal pouch both in symptomatic patients and in controls as evidenced by the acid pH reaction. The proximal pouches of patients with stomal ulcer were significantly more exposed to acid compared to controls. The median percentage of time with pH <4 was 69% and 20% in the stomal ulcer and the control group, respectively (P<0.01). Barium follow-through excluded gastro-gastric fistula in stomal ulcer patients. CONCLUSION: RYGBP patients with stomal ulcer have increased acid production in their proximal pouch in comparison with asymptomatic RYGBP patients. Gastric acid appears to have an important role in the pathogenesis of stomal ulcer.

Adult↗