‘Crystal-like structures’ of boiled beef heart mitochondria

Electron micrographs of boiled beef heart mitochondria are presented. On heating the mitochondrial suspension for 7 min in a boiling water bath ‘crystal-like’ structures inside and inbetween the mitochondria became visible.     

Gas chromatographic analysis of urinary dimercaptosuccinic acid

The therapeutic use of disulfhydryl compounds such as 2,3-dimercaptosuccinic acid (DMSA) for the treatment of heavy metal poisoning has generated a requirement for specific and sensitive methods to determine those compounds in biological media. We have developed a gas chromatographic assay for DMSA in urine. The use of capillary column technology eliminates the requirement for a preliminary clean-up step. Samples are first reduced electrochemically to liberate DMSA present as disulfides. The reduced product is then extracted into ethyl acetate and the organic phase removed by evaporation. The residue is derivatized with N,O-bis(trimethylsilyl)acetamide for gas chromatography. The silylated DMSA derivative is then detected with a flame ionization detector. The detection limit for DMSA is 1.9 nmol per 1-μl aliquot of derivatized extract injected on column (detector sensitivity at 1·10⁻¹¹ A/mV). The utility of the method was demonstrated by analyzing the urine of rats orally dosed with DMSA.     

Gas chromatographic analysis of hexosamines in glycoproteins

A gas chromatographic method for the analysis of hexosamines in glycoproteins was described which uses the alditol acetate derivatives of the sugars. A polyamide (Poly A 103) liquid phase was used which effectively separates glucosamine, galactosamine, and mannosamine from each other. Mannosamine served as internal standard to facilitate accurate quantitation of glucosamine and galactosamine.     

Gas-liquid chromatographic analysis of volatile short chain fatty acids in fecal samples as pentafluorobenzyl esters.

A protocol was developed for the analysis of volatile short chain fatty acids in microsamples of feces, short chain fatty acid (SCFA) extraction was from fecal samples using ethanol incorporating n-hexanoic acid as an internal standard. The SCFAs were converted to pentafluorobenzyl esters with alpha-2,3,4,5,6-pentafluorotoluene and analyzed on a gas-liquid chromatograph equipped with an electron capture detector. One hundred milligrams of sample was routinely used but analysis could be carried out on 20 mg of sample.     

Gas chromatographic headspace analysis of sevoflurane in blood

We have developed a rapid, simple and precise gas chromatographic headspace analysis for sevoflurane in blood which circumvents problems associated with the high volatility and low blood/gas partition coefficient of this anesthetic drug. Blood standards are easily prepared by volumetric addition of a saturated aqueous solution of sevoflurane. Likewise, internal standardization is achieved using a saturated aqueous solution of halothane. Chromatographic conditions are similar to those commonly used for the analysis of blood ethanol. A simple method is also described for the preparation of stable and precise aliquots of quality control materials for this assay.     

The volatile bases of cigar smoke

The following pyridine bases were isolated from cigar smoke condensate using temperature programmed gas chromatography: pyridine; α-, β-, and γ-picoline; 2,3-, 2,4-, 2,5-, and 2,6-lutidine; 3-ethylpyridine; 3-vinylpyridine; nicotine; nornicotine; myosmine, and 2,3′-dipyridyl. Tentative identifications were also obtained for 3,5-lutidine and 3-acetylpyridine. Semiquantiative measurements on the amounts of these compounds present in the smoke condensate were obtained.     

Dry-column chromatographic purification of aflatoxin precursors

The toxic and carcinogenic properties of aflatoxins are well understood, but little is known about the biological activity of the anthraquinone precursors of aflatoxin. This paper describes a dry column chromatographic method for preparing averantin, averufin, norsolorinic acid and versicolorin A from mycelial extracts of blocked mutants of Aspergillus parasiticus in quantities suitable for toxicological testing.     

Gas chromatographic analysis of oxidation products of adrenal corticosteroids

Gas chromatographic separations of periodic acid and sodium bismuthate oxidation products of corticosteroids, including cortexolone, cortisone, cortisol, prednisolone, deoxycorticosterone, dehydrocorticosterone, and corticosterone, were investigated using SE-30, QF-1, and XE-60 phases.     

Peroxidase-positive mononuclear leukocytes as possible precursors of human dendritic reticulum cells

In this report, we provide evidence that suggests the dendritic reticulum cells (DRC) occurring in germinal centers of lymphatic follicles originate from a distinct endogenous peroxidase-positive mononuclear blood cell subset. The new monoclonal antibody Ki-M4 showed a highly restricted reactivity, tested by immune histochemistry, being confined to DRC, lining cells of lymph node sinuses, and to 0.001% of nonadherent mononuclear blood cells separated at a density of 1.077 g/ml; the latter exhibited endogenous peroxidase activity in cytoplasmic granules. Such granules being specific for myelomonocytic cells implies that DRC may derive from a committed nonadherent subpopulation of this cell line, which in turn originates from bone marrow. The Ki-M4-reactive antigen was found to be destroyed by the majority of fixatives and to resist 4% paraformaldehyde for 10 min and cold acetone for 30 sec. In cell suspensions from human tonsils, Ki-M4 showed strong reactivity with the outer surface of DRC plasma membrane. This observation demonstrates the possibility of using Ki-M4 to separate DRC from cell suspensions in functional tests.     

Gas chromatographic analysis of nicotine and cotinine in hair

Non-invasive validation of cigarette- or cigar-smoking behaviour is necessary for large population studies. Urine or saliva samples can be used for confirmation of recent nicotine intake by analysis of cotinine, the major metabolite of nicotine. However, this test is not suitable for validation of survey data, since the quantification of cotinine in saliva only reflects nicotine exposure during the preceding week. To validate information on tobacco use, we investigated hair samples for quantifying nicotine and cotinine by gas chromatography—mass spectrometry. Hair (about 50–100 mg) was incubated in 1 M sodium hydroxide at 100°C for 10 min. After cooling, samples were extracted by diethyl ether, using ketamine as an internal standard. Drugs were separated on a 12-m BP-5 capillary column, and detected using selected-ion monitoring (m/z 84, 98 and 180 for nicotine, cotinine and ketamine, respectively). Hair from non-smokers and smokers contained nicotine and cotinine. Although it is difficult to determine an absolute cut-off concentration, more than 2 ng of nicotine per milligram of hair can be used to differentiate smokers from non-smokers. Some applications of this technique are developed to determine the status of passive smokers, the gestational exposure in babies and the pattern of an individual's nicotine use by cutting strands of hair into sections of one-month intervals.