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Biomedical subjects

R Kraft

Publications and source records attributed to R Kraft.

At least 181 records · Page 10Linked to original sources
PubMed1979

[Midline granuloma. A review of the literature with particular reference to diagnostic and therapeutic problems supplemented by 3 personal case reports].

The term midline granuloma and various synonyms have been used to describe a rare lesion that ultimately forms a necrotizing ulcerating destruction of the midface. The aetiology has been variously and repeatedly discussed, and a review of the literature shows that at least three entities, which are difficult to differentiate, should be considered. Wegener's granulomatosis, malignant lymphoma and atypical histiocytic lymphoma, a disease with a pleomorphic histology, may all have an extensive necrosis and an intense inflammatory reaction. Upon the diagnosis, which is confirmed by biopsy, depends the appropriate treatment of these fatal diseases. The collective term midline granuloma should be avoided since it may delay the correct management.

Adolescent↗
PubMed1979

[Biotransformation and Stability of Hydrocotarnine and Diazocarbonylhydrocotarnine and -hydrohydrastinine derivatives (author's transl)].

After oral application of the weakly basic (pKs = 6.18-6.26) and relatively stable (1 at pH = 7.4; t1/2(35 degrees C) = 6.9 h) secondary 1-diazocarbonylhydrocotarnine or -hydrohydrastinine derivatives 1-4 and of hydrocotarnine (6) to rats, a total of 18 metabolites, predominantly isoquinolines of varying degrees of hydrogenation (7-19), were isolated from 48-hour urine specimens. These isoquinolines result from cleavage of the C-1/C-1' bond as well as from oxygenation (11, 15, 17-19), N-dealkylation (13, 15, 17-19) and O-dealkylation (8-12, 18, 19). Among these isoquinolines were some phenolic betaines (8-11) of which 9 is the major metabolite of the cotarnine derivatives. Furthermore, C-1-substituted metabolites as well as metabolites with benzo-1,2-diazaindolizine (23, 24) or benzodiazepine structure (20, 21) were isolated. Also in an aqueous-alkaline or an aqueous-acidic medium, the cleavage of the C-1/C-1' bond as well as the formation of benzodiazepines follows a non-enzymatic pathway as evidenced by stability studies. The structures assigned to the different compounds are supported by high-resolved mass spectra, further spectroscopic studies (UV, IR and 1H-NMR spectra) and, in part, by comparison with authentical material.

Animals↗
PubMed1978

Dioxygen and temperature dependence of ubiquinone formation in Escherichia coli: studies of cells charged with 2-octaprenyl phenol.

The multiple aromatic auxotroph Escherichia coli K-12 strain AB 2847 (aroB-) was conditioned for efficient ubiquinone-8 formation. Resting cells readily convert 4-hydroxy[U-14C]benzoate into ubiquinone-8 (60 nmol per g wet weight). Under argon this processing stops at the stage of 2-octaprenyl phenol. Only upon admission of air is the pool of 2-octaprenyl phenol converted to ubiquinone-8. This reaction occurs in the cytoplasmic membrane and is significantly inhibited by cytochrome P-450 inhibitors. The rate for 2-octaprenyl phenol conversion is strongly dependent on temperature. The Arrhenius plot shows inflection points at 32 degrees C and 16 degrees C. Enzymes for ubiquinone-8 synthesis are absent from anaerobically grown E. coli. Processing of 4-hydroxy[U-14C]benzoate by these cells starts only when protein synthesis is permitted under aerobic conditions.

Cytochrome P-450 Enzyme System↗
PubMed1978

Mass spectroscopy of natural products. III--Mass spectrometric comparison of lysergic acid and 9,10-dihydrolysergic acid.

The influence of the 9,10-double bond in the ergoline skeleton on the fragmentation behaviour of lysergic acid and 9,10-dihydrolysergic acid is discussed. The main fragmentation pathways were determined using high resolution mass spectrometry and metastable ion studies. The 70 eV electron impact spectra are compared with the 12 eV electron impact spectra and the negative ion mass spectra (2--4 eV).

Ergolines↗
PubMed1975

[The determination of chloride in plasma and serum (mercury(II)-thiocyanate method) with the Greiner Electronic Selective Analyzer GSA II (author's transl)].

1. A mercury(II)-thiocyanate method for the determination of chloride in plasma and serum was adapted for the Greiner Electronic Selective Analyzer GSA II. A sample blank value and a partial reagent blank value were determined by omitting thiocyanate from the control system. 2. The course of the reaction was investigated. For a reaction time of 350-500 s, the response was linear between 30 and 130 mmol/l. Between 90 and 110 mmol/l, the deviation between the actual and the theoretical value is less than 1%. 3. The calibration must be checked and, if necessary, restandardized; this is probably due to variable contamination of the reagents with chloride ions. 4. Haemolysis, lipaemia and bilirubin do not interfere. Protein has no effect on the course of the reaction. 5. At concentrations around 100 mmol/l, the in series precision, expressed as the variation coefficient (%), is 0.3-0.6% for aqueous solutions, 0.4-0.8% for liquid control sera, and 0.8-1.5% for lyophilized control sera. 6. No carry over was detectable from samples containing 150 to those containing 10 mmol/l.

Autoanalysis↗