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Biomedical subjects

W Aberer

Publications and source records attributed to W Aberer.

137 records · Page 8Linked to original sources
PubMed1982

[Stevens-Johnson syndrome and toxic epidermal necrolysis following intake of sulfonamides].

Sulfonamides, particularly in combination with trimethoprim, are among the most commonly prescribed antimicrobial chemotherapeutic agents since they are generally well tolerated and have a broad antibacterial spectrum. However, they are the most common cause of adverse cutaneous drug reactions, the most serious of which are the major variant of erythema multiforme, i.e. Stevens-Johnson-syndrome, and toxic epidermal necrolysis. In eight of 11 patients with Stevens-Johnson syndrome or toxic epidermal necrolysis seen in our department over a period of 4 years, sulfonamides were the most probable causative agent. The present report describes these eight patients and discusses the potential risks of sulfonamide therapy.

Aged↗
PubMed1981

Ultraviolet light depletes surface markers of Langerhans cells.

This report defines the influence of ultraviolet light (UV) on Langerhans cells (LC). Human volunteers and hairless mice (Swiss ha/ha) were exposed to various single and/or cumulative doses of either UV-A, UV-B, or UV-A plus small amounts of UV-B (UV-A (+B)). 24 hr after the last irradiation, morphology of the entire epidermis was evaluated by both light and electron microscopy while LC, in addition, were tested for expression of specific histochemical (ATPase) and functional immunological markers (Ia antigens). In both men and mice, cumulative doses of either 80-120 J/cm2 UV-A (+B) or 1-2 X 100 J/cm2 UV-A resulted in a dramatic reduction of cells exhibiting ATPase and Ia-reactivity. In the UV-B spectrum, single doses of 60-80 mJ/cm2 produced a virtually complete elimination of LC membrane markers. By contrast, pemphigus antigens of keratinocytes were unaffected by these energy doses. Electron microscopy revealed cellular damage of some LC after UV-doses which produce a virtually complete abolition of LC membrane markers. At certain dose ranges (15-30 mJ/cm2 UV-B and 1 x 40 to 2 x 100 J/cm2 UV-A) LC were the only epidermal cells to display morphological damage at the ultrastructural level whereas higher doses affected all epidermal cells. The finding that LC surface markers and to a lesser extent the cells themselves are particularly susceptible to UV irradiation has important implications in view of previous findings that LC are potent stimulators of antigen-specific and allogeneic T cell activation. UV-induced alteration of LC plasma membrane integrity may represent a tool to manipulate adverse immune reactions involving the epidermis.

Adenosine Triphosphatases↗
PubMed1978

Particle segregation in chromaffin granule membranes by forced physical contact.

Bovine chromaffin granules were exposed to different isotonic non-ionic and ionic solutions (sucrose; Ca2+- and Mg2+-free phosphate-buffered saline; Tris-HCl + NaCl; Ca2+- and Mg2+-free phosphate-buffered saline + sucrose; Tris-HCl + sucrose) at pH 7 and then frozen either in suspension or as firm pellets. Freezing was performed without prefixation or antifreeze treatments either by 'standard' techniques (approx. 1 mm3 suspended or pelleted material on gold specimen supports dipped into liquid Freon) or with increased cooling rates by spraying suspensions into liquid propane ('spray-freezing'). Regardless of the freezing method, membrane-intercalated particles were always randomly distributed when chromaffin granules were frozen in suspension. In contrast, forced physical contact between granules produced by centrifugation (12000 X g, 25 min) provoked dispersal of membrane-intercalated particles, but only in the presence of ions. Sucrose or EDTA in an ionic environment had no inhibitory effect. The following conclusions are derived: (1) Even below the reported phase transition region particle clustering is possible. (2) Chromaffin granule membranes are not liable to thermotropic segregation of membrane-intercalated particles. (3) Although the low freezing rates of 'standard' freezing techniques produce large-scale segregation artefacts (by which suspended chromaffin granules are pushed together within the segregated solute) this does not result in intramembraneous particle segregation. (4) Forced physical contact produces a Ca2+-independent particle segregation, but only when repulsive electrostatic forces of membrane components are partially screened in an ionic environment. (5) This does not invalidate results obtained by others, showing Ca2+-mediated chromaffin granules agglomeration and segregation of membrane-intercalated particles, but it might indicate the occurrence of another, not directly Ca2+-dependent particle segregation mechanism in a prefusional stage of close membrane-to-membrane contact during exocytosis.

Animals↗
PubMed1978

A characterization of the nucleotide uptake of chromaffin granules of bovine adrenal medulla.

Chromaffin granules isolated from bovine adrenal gland were incubated with (3)H-labelled nucleotides and [(14)C]noradrenaline to study the uptake of these substances. [(3)H]ATP, [(3)H]ADP and [(3)H]AMP are taken up by these organelles by the same temperature-dependent mechanism. The apparent K(m) for ATP and ADP is 1.4mm, and for AMP it is 2.9mm. The uptake of ATP has a flat pH optimum, whereas the catecholamine uptake increases with more alkaline pH. Atractyloside and carboxyatractyloside are competitive and specific inhibitors of nucleotide uptake, whereas reserpine inhibits only that for catecholamines. Mg(2+) ions activate uptake of both catecholamine and nucleotides, whereas EDTA and N-ethylmaleimide inhibit these processes. Nucleotide and catecholamine uptakes are inhibited by uncouplers of oxidative phosphorylation and by two ATP analogues. NH(4) (+) ions and nigericin in the presence of KCl inhibit only catecholamine uptake. It is concluded that nucleotide uptake, as proposed previously for catecholamine uptake, depends on an electrochemical proton gradient produced by a proton-translocating adenosine triphosphatase localized in the membrane of chromaffin granules. Furthermore, as suggested by the effect of NH(4) (+) and nigericin, catecholamine uptake apparently depends on the chemical part of this gradient, whereas the results for nucleotide uptake are consistent with its dependence on the electrical component.

Adenosine Diphosphate↗
PubMedDate not supplied

Cross-reacting allergens in tree pollen and pollen-related food allergy: implications for diagnosis of specific IgE.

BACKGROUND: A number of recombinant allergens are by now constituents of devices that can be routinely used for the detection of specific IgE. Therefore, the results of diagnostic procedures using conventional allergen extracts can be compared with those employing selected recombinant allergens. METHODS: Thirty-four sera from patients allergic to birch pollen were tested with the standard t3-CAP and rBet v 1a- and rBet v 2-CAP. cDNA was prepared by RT-PCR using primers according to the N terminus of purified allergens. Expression cDNA libraries were screened with IgE from selected patients. RESULTS: Twenty-four patients allergic to birch pollen showed the same RAST class with t3 as with rBet v 1a; 8 patients differed within 1 RAST class. In addition, 3 patients showed RAST class 3 with rBet v 2. Besides Bet v 1 and Bet v 2, 3 allergens from celery and avocado belonging to highly conserved protein families were cloned and sequenced. CONCLUSIONS: rBet v 1a can be expected to represent an excellent tool for the diagnosis of patients allergic to birch pollen in Central, Northern, and Eastern Europe. Still, a much higher number of patients has to be tested. For their high degree of conservation, further protein families have to be identified to explain cross-reactivities of birch pollen allergens other than Bet v 1 and Bet v 2 with, e.g., allergens from vegetable food.

Allergens↗
PubMedDate not supplied

[The "false-positive" patch test reaction].

If a positive patch test reaction occurs in the absence of sensitization to a certain antigen, we call it a false positive reaction. There may be several reasons for this: impurities of the test substances, too high a concentration, wrong choice of test location and reading time; positive reactions against test vehicle, or adhesive tape, nonspecific reactions due to adjacent strongly positive patch test reactions and finally wrong interpretation by the doctor. Diagnosis of contact allergy, especially to potent allergens or topical medications and questions relating to occupational disease may be of eminent importance to the patient. Therefore false positive as well as false negative test reactions should be recognized; this also appears particularly important for medicolegal reasons.

Dermatitis, Contact↗
PubMedDate not supplied

[The spectrum of Lyme borreliosis from the dermatologic viewpoint].

Erythema chronicum migrans, lymphadenosis benigna cutis and acrodermatitis chronica atrophicans represent the dermatological manifestations of the multi-organ disease Lyme borreliosis. Koch's requirements of evidence for an infectious disease, demonstration of the bacterium, transfer, and culture have proven Borrelia burgdorferi to be the causative agent of the above mentioned skin diseases. This justifies a penicillin therapy, that has been administered in Europe empirically for the last 30 years. Correct and prompt diagnosis is important since delayed treatment is less effective, presumably because the spirochete becomes sequestered in immune-privileged sites. Recent observations in several laboratories that antibody titers to Borrelia burgdorferi are also elevated in several other skin diseases and that the spirochete can be detected in tissue sections of different organs may imply extension of the dermatological spectrum of Lyme disease. The significance of these findings in such heterogeneous diseases as morphea, lichen sclerosus et atrophicans, etc. however awaits final examination.

Acrodermatitis↗