Biomedical subjects

A Wahl

Publications and source records attributed to A Wahl.

At least 19 recordsLinked to original sources

PubMed2006

Fluorescence quencher improves SCANSYSTEM for rapid bacterial detection.

BACKGROUND AND OBJECTIVES: The optimized scansystem could detect contaminated platelet products within 24 h. However, the system's sensitivity was reduced by a high fluorescence background even in sterile samples, which led to the necessity of a well-trained staff for confirmation of microscope results. MATERIALS AND METHODS: A new protocol of the optimized scansystem with the addition of a fluorescence quencher was evaluated. Pool platelet concentrates contaminated with five transfusion-relevant bacterial strains were tested in a blind study. RESULTS: In conjunction with new analysis software, the new quenching dye was able to reduce significantly unspecific background fluorescence. Sensitivity was best for Bacillus cereus and Escherichia coli (3 CFU/ml). DISCUSSION: The application of a fluorescence quencher enables automated discrimination of positive and negative test results in 60% of all analysed samples.

Bacteriological Techniques↗

PubMed2005

Safety and exercise tolerance of acute high altitude exposure (3454 m) among patients with coronary artery disease.

OBJECTIVES: To assess the safety and cardiopulmonary adaptation to high altitude exposure among patients with coronary artery disease. METHODS: 22 patients (20 men and 2 women), mean age 57 (SD 7) years, underwent a maximal, symptom limited exercise stress test in Bern, Switzerland (540 m) and after a rapid ascent to the Jungfraujoch (3454 m). The study population comprised 15 patients after ST elevation myocardial infarction and 7 after a non-ST elevation myocardial infarction 12 (SD 4) months after the acute event. All patients were revascularised either by percutaneous coronary angioplasty (n = 15) or by coronary artery bypass surgery (n = 7). Ejection fraction was 60 (SD 8)%. beta blocking agents were withheld for five days before exercise testing. RESULTS: At 3454 m, peak oxygen uptake decreased by 19% (p < 0.001), maximum work capacity by 15% (p < 0.001) and exercise time by 16% (p < 0.001); heart rate, ventilation and lactate were significantly higher at every level of exercise, except at maximum exertion. No ECG signs of myocardial ischaemia or significant arrhythmias were noted. CONCLUSIONS: Although oxygen demand and lactate concentrations are higher during exercise at high altitude, a rapid ascent and submaximal exercise can be considered safe at an altitude of 3454 m for low risk patients six months after revascularisation for an acute coronary event and a normal exercise stress test at low altitude.

Aged↗

PubMed2005

MR coronary artery imaging with 3D motion adapted gating (MAG) in comparison to a standard prospective navigator technique.

Magnetic resonance coronary angiography (MRCA) has been proven to be feasible for imaging of the proximal and medial portions of the three main coronary arteries. Free breathing techniques allow for high resolution imaging but prolong scan time. This could potentially be shortened by improving the efficiency, robustness and accuracy of the navigator gating algorithm. Aim of this study was to determine the feasibility, efficiency, and image quality of a new motion compensation algorithm (3D-MAG) for coronary artery imaging with navigator techniques. In 21 patients the coronaries were imaged in plane with a 3D k-space segmented gradient echo sequence. A T2 preparation prepulse was used for suppression of myocardial signal, during free breathing and a navigator technique with using real time slice following and a gating window of 5 mm was applied to suppress breathing motion artefacts. Imaging was performed with standard gating and compared to 3D-MAG. Image quality was visually compared, contrast-to-noise and signal-to-noise ratio were calculated, the length of visualized coronary arteries was measured and scan duration and scan efficiency were calculated. Standard navigator imaging was feasible in 19 of 21 (90.5%) patients 3D-MAG in 21/21 (100%). Scan efficiency and duration was significantly improved with 3D-MAG (p < .05) without change in image quality. 3D-MAG is superior to conventional navigator correction algorithms. It improves feasibility and scan efficiency without reduction of image quality. This approach should be routinely used for MR coronary artery imaging with navigator techniques.

Algorithms↗

PubMed2004

Comparison of dobutamine stress magnetic resonance, adenosine stress magnetic resonance, and adenosine stress magnetic resonance perfusion.

BACKGROUND: Dobutamine stress MR (DSMR) is highly accurate for the detection of inducible wall motion abnormalities (IWMAs). Adenosine has a more favorable safety profile and is well established for the assessment of myocardial perfusion. We evaluated the diagnostic value of IWMAs during dobutamine and adenosine stress MR and adenosine MR perfusion compared with invasive coronary angiography. METHODS AND RESULTS: Seventy-nine consecutive patients (suspected or known coronary disease, no history of prior myocardial infarction) scheduled for cardiac catheterization underwent cardiac MR (1.5 T). After 4 minutes of adenosine infusion (140 microg x kg(-1) x min(-1) for 6 minutes), wall motion was assessed (steady-state free precession), and subsequently perfusion scans (3-slice turbo field echo-echo planar imaging; 0.05 mmol/kg Gd-BOPTA) were performed. After a 15-minute break, rest perfusion was imaged, followed by standard DSMR/atropine stress MR. Wall motion was classified as pathological if > or =1 segment showed IWMAs. The transmural extent of inducible perfusion deficits (<25%, 25% to 50%, 51% to 75%, and >75%) was used to grade segmental perfusion. Quantitative coronary angiography was performed with significant stenosis defined as >50% diameter stenosis. Fifty-three patients (67%) had coronary artery stenoses >50%; sensitivity and specificity for detection by dobutamine and adenosine stress and adenosine perfusion were 89% and 80%, 40% and 96%, and 91% and 62%, respectively. Adenosine IWMAs were seen only in segments with >75% transmural perfusion deficit. CONCLUSIONS: DSMR is superior to adenosine stress for the induction of IWMAs in patients with significant coronary artery disease. Visual assessment of adenosine stress perfusion is sensitive with a low specificity, whereas adenosine stress MR wall motion is highly specific because it identifies only patients with high-grade perfusion deficits. Thus, DSMR is the method of choice for current state-of-the-art treatment regimens to detect ischemia in patients with suspected or known coronary artery disease but no history of prior myocardial infarction.

Adenosine↗

PubMed2004

Capillary electrochromatography with polymeric continuous beds synthesized via free radical polymerization in aqueous media using derivatized cyclodextrins as solubilizing agents.

A novel synthetic route to amphiphilic acrylamide-based monolithic stationary phases for capillary electrochromatography (CEC) employing water-soluble cyclodextrins as solubilizing agents was explored. N,N'-Octamethylenebisacryamide and N,N'-dodecamethylenebisacryamide were synthesized and their solubilization in aqueous solution with derivatized and underivatized cyclodextrins of different cavity size was studied. Amphiphilic stationary phases were synthesized by free radical copolymerization of the bisacrylamide-cyclodextrin host-guest complexes with hydrophilic monomers and an additional hydrophilic cross-linker in aqueous solution. Complex formation in solution and removal of the complexed cyclodextrin from the polymer during synthesis was studied with 1H-NMR and solid state 13C-NMR spectroscopy and cyclodextrin-modified micellar electrokinetic chromatography. The impact of the incorporated alkylene groups in the acrylamide-based macroporous polymer on retention was studied with neutral solutes by CEC in the normal-phase elution mode and in the reversed-phase elution mode. Batch-to-batch reproducibility of the synthesis procedure and day-to-day repeatability of the separations achieved were investigated. With these capillaries, a sufficiently high electroosmotic flow velocity, a high reproducibility and repeatability of separation parameters and high plate numbers (up to 200,000 m(-1) were obtained.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed2004

Percutaneous closure of patent foramen ovale reduces the frequency of migraine attacks.

Among 215 patients referred for percutaneous closure of patent foramen ovale (PFO) after presumed paradoxical embolism, we assessed the prevalence of migraine. In the year prior to PFO closure, 48 (22%) patients had migraine, twice the expected prevalence of 10 to 12% in the general European population. In patients with migraine with aura, percutaneous PFO closure reduced the frequency of migraine attacks by 54% (1.2 +/- 0.8 vs 0.6 +/- 0.8 per month; p = 0.001) and in patients with migraine without aura by 62% (1.2 +/- 0.7 vs 0.4 +/- 0.4 per month; p = 0.006). PFO closure did not have an effect on headache frequency in patients with nonmigraine headaches (1.4 +/- 0.9 vs 1.0 +/- 0.9 per month; p = NS).

Adult↗

PubMed2004

Percutaneous closure of patent foramen ovale: impact of device design on safety and efficacy.

OBJECTIVE: To compare the safety and efficacy of percutaneous closure of patent foramen ovale (PFO) with the Amplatzer PFO occluder (Amplatzer) or the PFO STAR device (STAR) in patients with presumed paradoxical embolism. METHODS: Implantation characteristics, procedural complications, residual shunt, and recurrence of thromboembolic events were recorded prospectively in 100 consecutive patients undergoing percutaneous PFO closure with the STAR (n = 50) or Amplatzer (n = 50) devices between 1998 and 2001. The study was not randomised. Device implantation was successful in all cases. RESULTS: There were more procedural complications in the STAR than in the Amplatzer group (8/50 v 1/50, p = 0.01). More than one device placement attempt was an independent predictor of procedural complications (odds ratio (OR) 8.5, 95% confidence interval (CI) 1.3 to 55.8; p = 0.03). A residual shunt six months after PFO closure, assessed by transoesophageal contrast echocardiography, occurred more often in the STAR than the Amplatzer group (17/50 v 3/50, p = 0.004), and was predicted in the STAR group by the use of a device with a 5 mm as opposed to a 3 mm disc connector (OR 6.1, 95% CI 1.1 to 34.0; p = 0.04). The actuarial risk of recurrent thromboembolic events after 3.5 years was 16.8% (95% CI 7.6% to 34.6%) in the STAR and 2.7% (95% CI 0.4% to 17.7%) in the Amplatzer group after three years (p = 0.08). CONCLUSIONS: Percutaneous PFO closure with the Amplatzer PFO occluder had fewer procedural complications and was more likely to be complete than with the STAR device. These findings underline the importance of device design for successful percutaneous PFO closure.

Balloon Occlusion↗

PubMed2004

How patients with diabetes who have foot and leg ulcers perceive the nursing care they receive.

OBJECTIVE: This Norwegian study set out to explore the nursing care experienced by patients with diabetes who have a foot and/or leg ulcer. METHOD: A qualitative method was used, with in-depth recorded interviews of patients living at home and receiving district nursing care. Seven patients were interviewed at home for 45 minutes to two hours. Interviews were transcribed and analysed using Kvale's thematic and meaning analysis. RESULTS: Several themes emerged, even though sample was not a homogeneous group: the expert patient (where patients acquired knowledge about their treatment and then passed this on to new and inexperienced nurses); fragmented nursing care (caused by lack of continuity in care); impersonal nursing care (where nurses did not view the patient as an individual, but focused solely on their wound); the ideal nurse (nursing attributes the patients valued most highly, such as engaging with them and attempting to understand their situation). CONCLUSION: Crucial to the successful treatment of patients with diabetes who have foot and/or leg ulcers is an understanding of their feelings about their ulcer and its impact on their quality of life. Further research in this area is recommended.

Adult↗

PubMed2003

[Cryptogenic stroke and patent foramen ovale].

A stroke of unknown etiology is commonly referred to as cryptogenic and is diagnosed in a considerable patient population of especially young age. Numerous case-control studies revealed a strong and consistent association between cryptogenic stroke and the presence of a patent foramen ovale. This relationship corroborates paradoxical embolism as likely stroke mechanism in this patient population. In approximately twenty-five percent of patients with cryptogenic stroke, the patent foramen ovale is accompanied by an atrial septal aneurysm, which considerably heightens the risk for recurrent neurological events. Therapeutic measures for secondary prevention in this patient population encompass medical treatment with antiplatelet agents or anticoagulants and surgical or percutaneous closure of patent foramen ovale. Currently, randomised clinical studies compare medical treatment with closure of patent foramen ovale to determine the most effective treatment strategy in this patient population.

Administration, Oral↗

PubMed2002

Breast cancer and experiences of social support. In-depth interviews of 10 women with newly diagnosed breast cancer.

The present study aimed to describe how 10 Norwegian women with newly diagnosed breast cancer experienced living with the disease. A qualitative method based on principles in Grounded Theory was used. Data were collected through in-depth interviews. This paper explores the experience of social support as it evolves in women's relationships with others. Social support contains emotional, practical and informative dimensions. Here relationships are called interactions. Interaction can be divided into two groups. Interactions with close relatives and others the women know and have contact with. Interactions with organizations and institution staff. These interactions consist of social support and lack of social support. Health professionals can assist women and their families in this life-threatening situation, by increasing their awareness of social support issues.

Adult↗

PubMed2002

Outcome of patients with cryptogenic stroke and patent foramen ovale.

OBJECTIVES: The aim was to estimate the recurrence rate and to define subgroups at increased risk for recurrent cerebral ischaemia in patients with patent foramen ovale (PFO) and so called cryptogenic stroke due to paradoxical embolism. METHODS: Patent foramen ovale was diagnosed in 318 patients with otherwise unexplained ischaemic stroke or transient ischaemic attack (TIA). One hundred and fifty nine were treated medically (oral anticoagulation 79, platelet inhibitors 80) and represent the study population. The remaining 159 patients underwent endovascular or surgical closure of the PFO and are not part of this study. RESULTS: Mean age was 50.7 (SD 13.5) years. The event leading to the diagnosis of PFO was a TIA in 38 patients (23.9%), an ischaemic stroke in 119 (74.8%), and an amaurosis fugax in two patients (1.3%). Forty four patients (27.7%) had experienced multiple cerebrovascular ischaemic events before the diagnosis of the PFO. During mean follow up of 29 (SD 23) months 21 patients (13.4%) had a recurrent cerebrovascular event (seven strokes and 14 TIAs). The average annual rate of recurrent strokes was 1.8% and that of recurrent strokes or TIAs was 5.5%. When patients with PFO with multiple cerebrovascular events before the diagnosis of the PFO were analyzed separately, the average annual rates of recurrent cerebral ischaemia were 3.6% for recurrent strokes and 9.9% for recurrent strokes or TIAs. These rates were significantly higher than in patients with first ever stroke or TIA (p=0.02). CONCLUSIONS: The study confirms a risk of stroke recurrence that is similar to the rates of previously published series of patients with PFO and cryptogenic strokes. Patients with more than one previous event were at increased risk of recurrent cerebral ischaemia.

Adolescent↗

PubMed2002

Nodular fasciitis, erythema migrans, and oligoarthritis: manifestations of Lyme borreliosis caused by Borrelia afzelii.

We describe a 35-year old patient with nodular fasciitis, erythema migrans, and gonarthritis four months after a bite of a Borrelia afzelii infected tick. The Borrelia afzelii infection was identified by a polymerase chain reaction and direct sequencing of the amplification product. Borrelia-specific DNA was also detectable in nodular fasciitis tissue. We therefore conclude that Borrelia afzelii can be a causative agent of nodular fasciitis and Lyme arthritis in a highly endemic region of Northern Germany.

Adult↗

PubMed2002

Coronary artery spasm and non-Q-wave myocardial infarction following intravenous ephedrine in two healthy women under spinal anaesthesia.

Vasovagal episodes occur frequently in young healthy patients undergoing venous cannulation and loco-regional anaesthesia. We report two cases of severe coronary vasospasm and non-Q-wave infarction in healthy young women after administration of ephedrine for vasovagal symptoms at the onset of spinal anaesthesia. In the light of unopposed vagal predominance pre-disposing patients to coronary vasospasm, even in young healthy patients, atrophine and not ephedrine should be the first line treatment for bradycardia with or without hypotension under spinal anaesthesia.

Adult↗

PubMed2001

Prognosis after percutaneous closure of patent foramen ovale for paradoxical embolism.

The long-term risk and risk factors for recurrent embolism after percutaneous closure of patent foramen ovale (PFO) were investigated in 152 consecutive patients with presumed paradoxical embolism. During follow-up, the actuarial freedom from recurrent embolism was 95.1% at 1 year, and 90.6% at 2 and 6 years. A residual shunt after percutaneous PFO closure was a predictor for recurrence (RR 5.3; 95% CI 1.3 to 21.0; p = 0.02). Randomized trials comparing medical treatment with percutaneous PFO closure in the prevention of recurrent embolism are in progress.

Adult↗

PubMed2001

Screening, confirmation and quantification of diuretics in urine for doping control analysis by high-performance liquid chromatography-atmospheric pressure ionisation tandem mass spectrometry.

A sensitive, selective, robust and fast method to identify 32 diuretics and masking agents in urine is described. The analytical procedure is reduced to a single XAD extraction step for sample preparation, followed by reversed-phase liquid chromatography in combination with atmospheric pressure ionisation/tandem mass spectrometry. This technique is, after minor modifications, suitable for screening analyses and confirmation of identity as well as quantitation of diuretics. Considerations relating to the stability and metabolism of the compounds are given if relevant for routine screening analyses.

Atmospheric Pressure↗

PubMed2001

Combined percutaneous pulmonary valvuloplasty and atrial septal defect closure for pulmonary valvular stenosis and associated secundum atrial septal defect in an adult.

Percutaneous balloon valvuloplasty is the treatment of choice for congenital pulmonary valve stenosis, and percutaneous closure of secundum atrial septal defects has become a promising alternative to surgery in selected patients. We report a case of combined percutaneous pulmonary valvuloplasty and secundum atrial septal defect occlusion in an adult patient.

Adult↗

PubMed2001

Functional cardiac MR imaging with steady-state free precession (SSFP) significantly improves endocardial border delineation without contrast agents.

Contrast between blood and myocardium in standard turbo gradient echo MR techniques (TFE) used routinely in clinical practice is mainly caused by unsaturated inflowing blood. Steady-state free precession (SSFP) has excellent contrast even in the absence of inflow effects. In 45 subjects cardiac cine loops in two long axis projections were acquired using TFE and compared with SSFP. A visual score (range 0 worst - 3 best) was assigned for endocardial border delineation for six myocardial segments in two long axis views. Endocardial border delineation score for TFE was 1.3 +/- 0.3 per segment and 2.4 +/- 0.3 for SSFP (P < 0.0001). Signal intensity blood/signal intensity myocardium was 1.5 +/- 0.4 at enddiastole and 1.4 +/- 0.3 at systole for TFE and 3.5 +/- 1.1 and 3.2 +/- 1.3 for SSFP, respectively (P < 0.0001). SSFP increases contrast between blood and myocardium more than twofold, resulting in an improved endocardial border definition. This may reduce variability for the determination of cardiac volumes and ejection fraction.

Adult↗

PubMed2001

Percutaneous closure of patent foramen ovale in symptomatic patients.

BACKGROUND: Patent foramen ovale (PFO) and atrial septal aneurysm (ASA) have been associated with stroke in young adults. Patients with PFO suffering from paradoxical embolism are at increased risk for recurrent events. Percutaneous PFO closure is a new treatment modality aimed at secondary prevention. METHODS AND RESULTS: Since April 1994, 132 consecutive patients, aged 51 +/- 12 years with PFO and with at least one paradoxical embolic event, underwent percutaneous PFO closure using six different device types. The embolic index event was an ischemic stroke in 62% of patients, a transient ischemic attack (TIA) in 33% of patients, and a peripheral embolism in 5% of patients. Thirty-six (27%) patients had PFO associated with ASA, whereas 96 (73%) patients had PFO only. The implantation procedure was successful in 130 (98%) patients. During and up to 6 years of follow-up (mean 1.8 +/- 1.6 years, 231 patient years), a total of eight recurrent embolic events were observed, with six TIAs, two peripheral emboli, and no ischemic stroke. The actuarial freedom from recurrence of the combined end point of TIA, ischemic stroke, and peripheral embolism was 95.3% (95% confidence interval [CI], 91.0%-96.4%) at 1 year and 90.5% (95% CI, 83.6%-97.2%) at 6 years. CONCLUSIONS: Percutaneous PFO closure can be performed with a high success rate. The procedure appears a promising therapeutic modality for secondary prevention of recurrent embolism in patients with PFO. Randomized trials must define its therapeutic value.

Adult↗