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Biomedical subjects

Stefan Wöhrl

Publications and source records attributed to Stefan Wöhrl.

9 recordsLinked to original sources
PubMed2006

Automated measurement of skin prick tests: an advance towards exact calculation of wheal size.

BACKGROUND: Using the Khoros image processing software environment, we developed a software-based system capable of extracting wheal size from skin prick tests (SPTs) in mm(2) for research and routine purposes. METHODS: At 20 min, the outlines of up to 20 wheals were marked with a pen and transferred with translucent adhesive tapes to a white paper form carrying predefined markings. The form was scanned at 200 dpi. The software automatically analysed the scanned image and calculated the sizes of the wheals. In a pilot study, serial SPTs with histamine in increasing dilutions were performed in 12 healthy volunteers in duplicate on both volar forearms. We matched the application results with a reference created from the scanned pictures. RESULTS: Bland-Altman analysis showed reference and software calculation reaching very high agreement. The comparison of reference/software resulted in a low centred coefficient of variation (COV) of 11.9%. This was superior to the conventional measurement of horizontal (COV 37.9%) or maximal/minimal diameter (COV 25.9%). CONCLUSION: We present an accurate tool for exactly calculating SPT wheal size in mm(2).

Adult↗
PubMed2006

Neurosyphilis is unlikely in patients with late latent syphilis and a negative blood VDRL-test.

Patients with latent syphilis or syphilis of unknown duration should be evaluated for tertiary disease and neurosyphilis. The aim of this retrospective study was to determine relevant serological parameters for the identification of those individuals with syphilis who are most likely to have neurosyphilis and who therefore require lumbar puncture. After excluding repeated estimates and patients whose blood syphilis serology had either been negative or not been determined within 3 months of lumbar puncture, 265 out of 710 cerebrospinal fluids from 1988 to 2004 were analysed. In each of those patients the earliest available pairs of serum and cerebrospinal fluid samples were evaluated. The diagnosis of neurosyphilis was based on criteria according to established guidelines. Forty-three of 265 patients (16.2%; 5 women, 38 men; mean age 47+/-16 years) had neurosyphilis. Seven of 72 (9.7%) of those testing HIV-positive, fulfilled the criteria of neurosyphilis. Not a single patient with neurosyphilis tested Venereal Disease Research Laboratory test (VDRL)-negative in peripheral blood, an effect which was highly significant (p < 0.01, chi2-test). The median blood-VDRL titre was significantly higher in patients with neurosyphilis than in those without (1:32 vs. 1:0; p < 0.01, t-test, two-sided). Hence, neurosyphilis is very unlikely in patients with a negative blood-VDRL. Therefore, lumbar puncture is not recommended in these patients.

Adult↗
PubMed2005

EMPACT syndrome.

BACKGROUND: Seizure prophylaxis with phenytoin is a common measure in oncologic patients with brain metastases. In these patients, generalized severe adverse drug reactions such as erythema multiforme (EEM) may occur. However, in a subgroup of patients with brain radiation therapy, EEM-like lesions develop particularly in the radiation field. Most recently, the acronym EMPACT (Erythema Multiforme associated with Phenytoin And Cranial radiation Therapy) was proposed to specifically describe this syndrome. PATIENT/METHOD: Here, we report on EMPACT syndrome in a 46-year-old woman. Therapeutic measures included seizure prophylaxis with phenytoin and total brain radiation therapy of brain metastases from bronchial carcinoma. Three weeks after introduction of phenytoin, the patient presented with EEM-like skin lesions restricted to the original radiation field and facial mucocutaneous involvement. After a few days, the rash spread to the upper part of the body. She was also in poor general condition. RESULTS: The immediate cessation of phenytoin therapy, combined with administration of systemic corticosteroids and high dose immunoglobulins along with intensive local treatment and pain medications, resulted in complete resolution of the skin eruption. Patch testing to phenytoin was positive after 72 hours. CONCLUSION: EMPACT should be classified as an specific entity among the EEM-like drug reactions as it only appears after radiotherapy and seizure prophylaxis with the anticonvulsant phenytoin. We propose including specific type IV-sensitization to phenytoin into the definition of EMPACT.

Adrenal Cortex Hormones↗
PubMed2005

Automatic measurement of skin wheals provoked by skin prick tests.

Skin prick tests (SPT) represent the standard method for the diagnosis of type-1 allergies. The skin wheals provoked by the SPTs are considered positive above certain cut-off diameters, usually 3 mm. At present their size is mostly estimated by measuring the diameter with rulers. Since the shape of wheals usually is not circular, the measurement of diameters leads to imprecise results. Therefore, we developed an algorithm for precisely measuring the wheals' area in mm(2) automatically. The average deviation of the automatic measurement on a test set achieved with the developed algorithm was 6.9 %. Compared to the maximum standard deviation of 6.59 % when measuring the manually redrawn outlines, the automatic method works sufficiently well.

Algorithms↗
PubMed2003

Molecular mechanisms of early electrical remodeling: transcriptional downregulation of ion channel subunits reduces I(Ca,L) and I(to) in rapid atrial pacing in rabbits.

OBJECTIVES: The purpose of the study was to characterize the ionic and molecular mechanisms in the very early phases of electrical remodeling in a rabbit model of rapid atrial pacing (RAP). BACKGROUND: Long-term atrial fibrillation reduces L-type Ca(2+) (I(Ca,L)) and transient outward K(+) (I(to)) currents by transcriptional downregulation of the underlying ionic channels. However, electrical remodeling starts early after the onset of rapid atrial rates. The time course of ion current and channel modulation in these early phases of remodeling is currently unknown. METHODS: Rapid (600 beats/min) right atrial pacing was performed in rabbits. Animals were divided into five groups with pacing durations between 0 and 96 h. Ionic currents were measured by patch clamp techniques; messenger ribonucleic acid (mRNA) and protein expression were measured by reverse transcription-polymerase chain reaction and Western blot, respectively. RESULTS: L-type calcium current started to be reduced (by 47%) after 12 h of RAP and continued to decline as pacing continued. Current changes were preceded or paralleled by decreased mRNA expression of the Ca(2+) channel beta subunits CaB2a, CaB2b, and CaB3, whereas significant reductions in the alpha(1) subunit mRNA and protein expression began 24 h after pacing onset. Transient outward potassium current densities were not altered within the first 12 h, but after 24 h, currents were reduced by 48%. Longer pacing periods did not further decrease I(to). Current changes were paralleled by reduced Kv4.3 mRNA expression. Kv4.2, Kv1.4, and the auxiliary subunit KChIP2 were not affected. CONCLUSIONS: L-type calcium current and I(to) are reduced in early phases of electrical remodeling. A major mechanism appears to be transcriptional downregulation of underlying ion channels, which partially preceded ion current changes.

Analysis of Variance↗
PubMed2003

Pemphigoid gestationis: treatment with immunoapheresis.

BACKGROUND: Pemphigoid (herpes) gestationis is a rare blistering disease of pregnancy. Topical and systemic corticosteroids and antihistamines are usually sufficient for treatment. CASE REPORT: A patient suffering from severe, therapy-resistant pemphigoid gestationis was successfully treated with the additional use of six sessions of immunoapheresis. Systemic corticosteroids could be tapered and serum autoantibody levels to bullous pemphigoid antigen 2 (BPAG2 = BP180) significantly dropped during this treatment. CONCLUSION: Immunoapheresis represents a helpful therapeutic option with few side effects for severe cases of pemphigoid gestationis, unresponsive to conventional treatment.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Patch testing in children, adults, and the elderly: influence of age and sex on sensitization patterns.

Patch testing was done on 2776 consecutive patients (76.5% female) with a locally revised standard series of 34 contact allergens and the results analyzed for age- and gender-specific differences. At least one positive epicutaneous test reaction occurred in 48.9% of patients. Nickel (20.9%), ethylmercuric chloride (13.2%), thimerosal (11.8%), fragrance mix (9.3%), metallic mercury (8.9%), palladium (5.8%), balsam of Peru (3.8%), copper (3.7%), cobalt (3.3%), and chromium (2.3%) were the 10 most important sensitizers. The following tested allergens with sensitization rates of more than 1% were not part of the usual standard series: ethylmercuric chloride, metallic mercury, copper, propolis (1.3%), propylene glycol (1.0%). Reactions to nickel, cobalt, and palladium, but not to chromium, were significantly more abundant in females (p < 0.002, chi-squared test). The overall sensitization rate was highest in children less than 10 years old (62%) and decreased steadily, to be lowest among patients more than 70 years old (34.9%). The rate of positive reactions to nickel and thimerosal decreased with age, while fragrance mix and metallic mercury stayed at the same level through all age groups.

Adolescent↗
PubMedDate not supplied

Histamine intolerance-like symptoms in healthy volunteers after oral provocation with liquid histamine.

Histamine in food at non-toxic doses has been proposed to be a major cause of food intolerance causing symptoms like diarrhea, hypotension, headache, pruritus and flush ("histamine intolerance"). Histamine-rich foods such as cheese, sausages, sauerkraut, tuna, tomatoes, and alcoholic beverages may contain histamine up to 500 mg/kg. We conducted a randomized, double-blind, placebo-controlled cross-over study in 10 healthy females (age range 22-36 years, mean 29.1 +/- 5.4) who were hospitalized and challenged on two consecutive days with placebo (peppermint tea) or 75 mg of pure histamine (equaling 124 mg histamine dihydrochloride, dissolved in peppermint tea). Objective parameters (heart rate, blood pressure, skin temperature, peak flow) as well as a total clinical symptom score using a standardized protocol were recorded at baseline, 10, 20, 40, 80 minutes, and 24 hours. The subjects received a histamine-free diet also low in allergen 24 hours before hospitalization and over the whole observation period. Blood samples were drawn at baseline, 10, 20, 40, and 80 minutes, and histamine and the histamine-degrading enzyme diamine oxidase (DAO) were determined. After histamine challenge, 5 of 10 subjects showed no reaction. One individual experienced tachycardia, mild hypotension after 20 minutes, sneezing, itching of the nose, and rhinorrhea after 60 minutes. Four subjects experienced delayed symptoms like diarrhea (4x), flatulence (3x), headache (3x), pruritus (2x) and ocular symptoms (1x) starting 3 to 24 hours after provocation. No subject reacted to placebo. No changes were observed in histamine and DAO levels within the first 80 minutes in non-reactors as well as reactors. There was no difference in challenge with histamine versus challenge with placebo. We conclude that 75 mg of pure liquid oral histamine--a dose found in normal meals--can provoke immediate as well as delayed symptoms in 50% of healthy females without a history of food intolerance.

Administration, Oral↗