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Biomedical subjects

H Ippen

Publications and source records attributed to H Ippen.

At least 19 recordsLinked to original sources
PubMed1990

Labilin.

Explore the source record for details and available documents.

Allergens↗
PubMed1990

[Effect of phototoxic substances on simple biological systems. I. Standardizing the method with furocoumarins].

As a basis for the investigation of new substances in respect of their photosensitization effects, we established and standardized 3 microbiological test systems, which enabled us to do without animal experiments. Using several furocumarines and various sources of light, we performed a comparative study on the eukaryotes, Chlamydomonas reinhardii (CR) and Candida albicans, and the prokaryote, Bacillus subtilis. We found that, if different light qualities were employed, our test systems also allowed a comparison of different substances by means of half-quantitative evaluation of the inhibiting areolas, which appear after exposure. With regard to the furocumarines, 8- and 5-methoxypsoralene (MOP) had the strongest photosensitizing effect under all test conditions. The remaining furocumarines showed decreasing effectiveness from psoralene to trimethylpsoralene (TMP) and imperatorine; psoralene, however, was slightly more effective in CR than 5-MOP. With the exception of CR, TMP had a stronger effect on the micro-organisms than imperatorine.

Animals↗
PubMed1990

Contact allergy to Phacelia spp. (Hydrophyllaceae).

Six persons involved with cultivation trials of Phacelia spp. developed a contact allergy to certain plants of this species. Geranyl(hydro)quinone and related substances, including the geranylhydroquinone geroquinol (INN), which has been introduced as a radioprotective agent, are potent allergens and probably are more often the cause of allergic eczema than is apparent from the literature.

Dermatitis, Contact↗
PubMed1989

Studies on uroporphyrinogen decarboxylase of etiolated Euglena gracilis Z.

1. A 423-fold purified fraction of uroporphyrinogen decarboxylase (EC 4.1.1.37) showing a specific activity of 770 units/mg protein has been employed in order to study some properties in etiolated Euglena gracilis Z. 2. Uroporphyrinogen decarboxylase has a relative molecular mass of 54,000, an optimum pH of 7.2 and exhibits Michaelis-Menten kinetics, employing both uroporphyrinogen I and uroporphyrinogen III as substrates. 3. Anaerobic conditions seem not to be necessary for uroporphyrinogen decarboxylase activity. Neither EDTA nor cysteine affected enzyme activity, whereas dithiothreitol produced a remarkable activation of coproporphyrinogen formation. 4. Kinetic data employing both substrates showed an accumulation of porphyrinogen (i.e. hexa- and hepta-porphyrin) containing six or seven COOH groups, depending on the uroporphyrinogen concentration used. 5. An unusual elution profile of the intermediates on Sephacryl S-200 was found.

Animals↗
PubMed1988

[Preparations containing sunscreens in West Germany 1988].

The commercial UV-absorbing cosmetics and sunscreens which are currently available in Germany are presented in two tables. In addition to the UV-absorbing and light-reflecting sunscreens, we list other ingredients which may cause skin reactions or have special properties. Our survey provides quick information on potential allergens and photoallergens. Well-tolerated alternative preparations can be chosen on the basis of the listed ingredients. Complete declaration of all ingredients in cosmetics and sun cosmetics is necessary in order to facilitate the diagnosis of allergies and photoallergies and should replace comprehensive surveys, which are rapidly outdated.

Chemical Phenomena↗
PubMed1988

[Photoallergic and allergic contact eczema caused by dibenzoylmethane compounds and other sunscreening agents].

Dibenzoylmethanes are widely used in Europe in UV-A-absorbing sunscreens. We report on 21 patients with (photo)allergic contact dermatitis from 4-isopropyl-dibenzoylmethane. Six subjects revealed, in addition, (photo)allergic reactions to 4-tert.butyl-4'-methoxy-dibenzoylmethane, seven to 3-(4-methylbenzylidene)-camphor, two to 2-phenyl-benzimidazole-5-sulfonic acid and one to 2-phenyl-5-methylbenzoxazole. Allergic contact dermatitis from 2-phenyl-benzimidazole-5-sulfonic acid has not been reported previously. The relevance of sunscreens as a cause of (photo-)allergic contact dermatitis is discussed.

Adolescent↗
PubMed1988

[Sunscreening agents in West Germany 1988].

The commercial UV-absorbing cosmetics and sunscreens which are currently available in Germany are presented in two tables. In addition to the UV-absorbing and light-reflecting sunscreens, we list other ingredients which may cause skin reactions or have special properties. Our survey provides quick information on potential allergens and photoallergens. Well-tolerated alternative preparations can be chosen on the basis of the listed ingredients. Complete declaration of all ingredients in cosmetics and sun cosmetics is necessary in order to facilitate the diagnosis of allergies and photoallergies and should replace comprehensive surveys, which are rapidly outdated.

Chemical Phenomena↗
PubMed1987

[Treatment of acute intermittent porphyria with a new protein-bound lyophilized hematin].

Hematin (iron-III-protoporphyrin 9) has been used for several years in the treatment of acute attacks of inducible porphyrias. Three patients were treated with a new, albumin-bound lyophilized hematin preparation (manufactured by Behringwerke). In all patients it achieved a reduction in the urine of the porphyrin precursors porphobilinogen and 5-aminolevulin acid. In two patients the clinical symptoms were clearly improved, while a third patient died with tetraparesis. Hematin administration proved superior to the preceding glucose treatment. No abnormality of clotting or thrombophlebitis was detectable after hematin infusion.

Acute Disease↗