Application of fast atom bombardment mass spectrometry to biological samples: analysis of urinary metabolites of acetaminophen

Fast atom bombardment (FAB) is useful for the characterization of all major metabolites of the analgesic acetaminophen (APAP). It is particularly useful for providing mass spectra of the polar glucuronide and sulfate conjugates which eluded identification by field desorption and other more conventional methods of ionization. A protocol is described for the use of FAB in the identification of urinary APAP metabolites isolated by reversed phase high-performance liquid chromatography (HPLC) following therapeutic dosages of the drug. A tentative set of recommendations for the off-line use of HPLC and FAB is directed towards solving problems encountered when using these two analytical techniques in concert. In addition, a method for calculating the signal to background ratio (S/B) for analyte peaks in FAB spectra from selected relative ion intensities is proposed. Examples are presented that show the potential of S/B as an empirical parameter for judging the quality of FAB spectra.     

Biosynthesis of the macrolide antibiotic chlorothricin: basic building blocks

The biosynthesis of chlorothricin (I), a macrolide antibiotic isolated from Streptomyces antibioticus Tü 99, has been studied by feeding experiments with 14C- and 3H-labeled precursors. Acetate and propionate, but not methionine and mevalonate, were incorporated into the macrocylic aglycone of the antibiotic. Glucose and the various carbon atoms of tyrosine, except the carboxyl carbon, also contributed label to the aglycone. Glucose also seems to be a specific precursor of the 2-deoxyrhamnose moiety, probably via a process involving a hydrogen shift from C-4 to C-6 of the hexose. The substituted 6-methylsalicylic acid moiety seems to be derived from acetate and one O-methyl group provided by methionine; shikimic acid is not incorporated.     

Problems associated with the assay of arylsulphatases A and B of rat tissues

A method for the separation and purification of rat liver arylsulphatases A and B by gel filtration on Sephadex G-200 is described. The properties of the A enzyme and its molecular weight are similar to those of the corresponding ox liver enzyme. The B enzymes were found to be dissimilar. The method already developed for the assay of the corresponding enzymes from human tissues was shown to be unsuitable for the assay of the enzymes of rat tissues. A method of assay was developed which permits an approximate determination of the individual rat liver enzymes in a mixture of the two, but precise determination requires prior separation of the enzymes by gel-filtration chromatography.     

Parathenar palmar pattern: a dermatoglyphic sign of possible clinical significance.

The frequency of a 'double proximal axial triradius' (DPAT), which results in a palmar parathenar pattern, has been reported to be increased in those with ventricular septal defect (BSD). We scored the presence of this pattern in 313 patients with congenital heart defects (including 86 with isolated VSD), 176 with cystic fibrosis (CF) or relatives of those with CF, and 333 with no known clinical disease who were unrelated to individuals with CF. The frequencies in these three groups were 1.6, 2.3, and 0.6%, respectively. None of those with isolated VSD defect had a DPAT. All five individuals in the heart defect group with a DPAT had pulmonic stenosis. Of the total of eleven individuals in our series with DPAT patterns, eight were affected only on the right hand. The frequency of DPAT in individuals with no known disease in this series was 4/406=1.0%, more than double the frequency in a control series, published previously by DAVID, 5/1,129=0.4%. If the 73 relatives of those with CF are excluded from our own 'control' group, the frequency of DPAT in this group is then 0.6%, closer to the results in DAVID's control series.     

Tritium uptake and elimination by tissue-bound and body-water components in crickets (Acheta domesticus)

Tritium concentration ratios of less than unity (0·19) were determined for adult crickets which were at equilibrium for that particular instar with a tritium tagged food source. This phenomenon is interpreted as meaning that simple diffusion-equilibrium assumptions are not adequate for describing tritium movement in food chains when true equilibrium conditions are not met. Additional factors, such as rates of tritium assimilation and turnover for tissue-bound and body-water fractions, food habits, and duration of developmental stages must be considered along with environmental tritium concentrations in determining food chain transfers of this radionuclide.