Lipid composition of leprosy-derived corynebacteria, a distinct group of corynebacteria, and of a reference Corynebacterium.

Leprosy-derived corynebacteria (LDC) are diphtheroid organisms isolated from leprosy patients and previously characterized by DNA and cell wall analysis. Three groups of LDC components of taxonomic value, glycolipids, and phospholipids and cell-wall-bound lipids were analyzed in comparison with those of a reference strain C. hoffmannii (CH). The main CH glycolipid, "cord factor" (trehalose dimycolate), was missing from LDC. Among phospholipids, phosphatidylinositol and phosphatidylglycerol had lowered proportions in LDC, as compared to CH, whereas phosphatidylethanolamine and cardiolipin were absent from both microorganisms. Bound lipids in acidic extracts of delipidated LDC yielded arabinose corynomycolate in lesser quantity with respect to CH. Alkaline hydrolysis of whole cells released fatty acids and mycolic acids, which were analyzed by gas chromatography/mass spectrometry. Reference CH, grown in the absence of serum, yielded C16:0 and C18:1 (major) and C18:0 (minor) fatty acids, as well as C32, C34, and C36 corynomycolic acids. All these components, particularly mycolates, had lowered proportions when this organism was grown in the presence of serum. Dominant LDC components were, in addition to C16:0, C18:0, and CI8:u fatty acids, cholesterol from serum. Very low concentrations of corynomycolic acids with a high degree of unsaturation were found in these organisms, suggesting a dependence of lipid metabolism on growth conditions. The presence in LDC of tuberculostearic acid (C19r:0), a mycobacterial component found in some pathogenic corynebacteria, was carefully explored: Traces of C19r:0 were found in LDC 19 grown in the presence of delipidated serum, but not in LDC 15 nor in C. hoffmannii. Present data, in conjunction with previous studies on DNA and mycolic acids, disclose basic differences in the composition of LDC and conventional corynebacteria.

Carboplatin in association with etoposide and either adriamycin or epirubicin for untreated small cell lung cancer: a dose escalation study of carboplatin. UCL Clinical Oncology Group.

A multi-center, open trial was conducted to determine the maximal tolerable dose of carboplatin in combination with conventional doses of both etoposide and an anthracycline for the treatment of previously untreated small cell lung cancer (SCLC) patients. Ninety-five patients [48 with limited disease (LD) and 47 with extensive disease (ED)] received a total of 376 courses of treatment. Carboplatin was given on day 1 at a dose of 250 mg m-2 in 60 courses, 300 mg m-2 in 69, 330 mg m-2 in 236 and 350 mg m-2 in 11, with 120 mg m-2 etoposide on days 1, 3 and 5 and either 40 mg m-2 adriamycin or 60 mg m-2 epirubicin on day 1. Epirubicin was not administered before carboplatin reached the dose of 330 mg m-2. Courses were repeated every 3 weeks. The main toxicity was hematological. The first course of therapy induced a dose-dependent decrease of leucocyte, neutrophil and platelet counts: all patients, except one, who received 350 mg m-2 carboplatin had a neutropenia below 200 microliters-1 and a thrombopenia below 100,000 microliters-1. Three patients died of septicemia. Other toxicities were well tolerated. After three courses, patients were re-staged by performing a mandatory fiberoptic bronchoscopy and a thoracic computed axial tomography (CAT). The overall objective response rate for 86 evaluable patients was 91% (98% for LD) with 21% complete remissions (30% for LD). All 23 hepatic and six brain sites, evaluable after chemotherapy alone, responded.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous detachment of benign mesothelioma into the pleural space and removal during pleuroscopy.

Benign pleural mesothelioma is a rare tumor which is usually diagnosed by thoracotomy in a patient with an intra-thoracic mass of uncertain origin. We report a case in which both diagnosis and therapy of a small, peripheral coin-lesion were achieved through thoracoscopy. The latter was performed following the observation that the tumor moved freely in the pleural space, because of an incidental pneumothorax.

Analysis of mycolic acids from a group of corynebacteria by capillary gas chromatography and mass spectrometry.

The cell wall of leprosy-derived corynebacteria (a group of 'diphtheroids' isolated from human leprosy lesions and patients' blood) was previously shown to contain, in addition to peptidoglycan and arabinogalactan, mycolic acids. These alpha-branched beta-hydroxy fatty acids were attributed to the corynomycolic group, according to their RF in monodimensional thin-layer chromatography. In the present work, mycolic acids from leprosy-derived and reference corynebacteria have been fractionated by monodimensional and bidimensional thin-layer chromatography and by gas chromatography. Pyrolyzed mycolic acids have been analyzed on conventional packed columns, whereas intact methyl esters of mycolic acids with free and silylated beta-hydroxyl group have been analyzed on capillary columns, and their structure has been established by mass spectrometry. In all leprosy-derived corynebacteria, some 20 components containing 24-36 carbon atoms and 0-4 double bonds were obtained. The three major groups had 32, 34 and 36 carbons, and the frequency of unsaturated versus saturated chains increased proportionally to the molecular weight. For comparison, the main components of a reference corynebacterium. Corynebacterium diphtheriae PW8, had 30 and 32 carbons, and their hydrocarbon chains were essentially saturated. This work confirms the relative chemical homogeneity of different leprosy-derived corynebacteria and describes some peculiar traits in the chemical structure of this group of organisms. In addition, it shows the complexity of the mycolic acid fraction of corynebacterial cell wall and suggests that the mycolic acid pattern is a sort of fingerprint of each bacterial strain grown under standard conditions. Finally, the fractionation of intact corynomycolic acid methyl esters with free or silylated beta-hydroxyl group by capillary gas chromatography proved to be the best analytical procedure at present available for resolving this complex mixture of corynomycolate isomers. Structural determination of silylated samples by mass spectrometry is preferred because they have more diagnostic fragments.

Chemical identification of some cell-wall components of microorganisms isolated from human leprosy lesions.

The cell walls of 24 coryneform non-acid-fast, Gram-positive organisms isolated from human leprosy lesion, were hydrolysed and analysed. Four known chemical markers of different high polymer components of the walls of microorganisms of the CMN (Corynebacterium, Mycobacterium, Nocardia) group were detected in whole cells and cell wall hydrolysates of the coryneform bacteria analyzed. These markers were: meso-diaminopimelic acid (peptidoglycan), arabinose and galactose (arabinogalactan), and mycolic acids. In addition, mycolic acids proved to be of the corynomycolic type, as shown by thin layer chromatography analysis. The conclusion was drawn that these coryneform strains independently isolated from patients of different countries, represent a homogeneous group within the genus Corynebacterium. This inference is supported by a parallel work showing that the guanine-plus-cytosine content of the DNA of these coryneform strains falls within the range of values characteristic of true corynebacteria pathogenic for animals.