Laboratory investigation of a poisoning epidemic in Sierra Leone.

In June 1986, an epidemic of poisoning occurred in Sierra Leone, West Africa; it involved 49 persons--with 14 deaths. Our laboratory's approach and investigation of this incident is described. Using positive chemical ionization mass spectrometry and nuclear magnetic resonance spectroscopy, the toxicant was identified as parathion, a highly toxic organophosphorus pesticide. Analysis of various items supported the epidemiologic hypothesis that bread was made from contaminated flour and that the flour became contaminated with parathion during a truck shipment. Modern analytical instruments played a major role in this laboratory investigation and effected the identification of the unknown toxicant within hours of receiving the initial bread sample. Close cooperation and clear communication between the epidemiologic and laboratory teams were important in this investigation.

Gas chromatographic and spectral properties of pentafluorobenzyl derivatives of 2,4-dichlorophenoxyacetic acid and phenolic pesticides and metabolites.

Eleven phenols and 2,4-dichlorophenoxyacetic acid, compounds that may be found in body fluids of humans exposed to pesticides, are derivatized with pentafluorobenzyl bromide and characterized by gas chromatography with electron capture detection. These derivatives are further characterized by positive and negative chemical ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and gas chromatography-Fourier transform infrared spectroscopy. Negative chemical ionization mass spectra of all derivatives have an anionic base peak derived from the parent analyte. In the positive mode the nonchlorinated derivatives have base peaks indicative of the analyte, while chlorinated derivatives are cleaved to give the pentafluorobenzyl cation as base peak. The possibility is explored that ortho-substituted phenols might be formed as byproducts in these derivatizations.

Frequency-pulsed electron-capture gas-liquid chromatographic studies of chemical changes in sera of patients with schistosomiasis.

Sera from well documented cases of Schistosoma mansoni and S. haematobium infections as well as controls, were studied by frequency-pulsed electron-capture gas--liquid chromatography (FPEL-GLC) and mass spectrometry for detection of carboxylic acids and amines. Many carboxylic acids and unidentified peaks were detected. In a few serum specimens from infected patients, putrescine and cadaverine were detected. Indications are that in these few patients with high egg counts enough diamines were present to possibly produce amine toxicity. Following the initial investigation, the basic chloroform extractions, which contained amines, were further studied by FPEC-GLC with the aid of splitless injection and a capillary column. Several amines were detected which seemed to be related to schistosomiasis. Mass spectra were obtained on an unidentified schistosamine peak. The possible significance of the data is discussed.

Identification of diethylene glycol in sera from Egyptian children by frequency-pulsed electron-capture gas-liquid chromatography.

Sera taken from fifteen patients (from Kerdasa village near Cairo, Egypt) infected with Schistosoma haematobium, with eggs present in the urine, were studied by frequency-pulsed electron-capture gas-liquid chromatography (FPEC-GLC). Some of the patients were treated with metrifonate and again studied by FPEC-GLC. Diethylene glycol was detected in the sera of untreated patients infected with S. haematobium. This compound was identified by negative chemical ionization and electron-impact mass spectrometry. Initially we suspected that the build-up of diethylene glycol in these patients was caused by schistosomiasis infection. However, in a follow-up blind-coded study using FPEC-GLC, which included 37 sera from Kerdasa and Tamooh villages near Cairo, Egypt, we detected diethylene glycol in eleven samples, four of which were controls from the villages. These latter findings indicate that the source of diethylene glycol might be the environment or foodstuffs, but the specific source has not been determined. Regardless of the source, diethylene glycol could affect the health of these Egyptian children by causing a narcotic effect, increased bladder stones, and increased numbers of bladder tumours.

Studies of metabolic changes in cell cultures infected with four serotypes of dengue fever viruses by frequency-pulsed electron-capture gas-liquid chromatography.

Monkey kidney cell cultures were infected with four serotypes of dengue viruses, and the supernatant fluids of the cell cultures were extracted for amines, alcohols, carboxylic acids, and hydroxy acids. The derivatized extracts were then analyzed by frequency-pulsed electron-capture gas-liquid chromatography (FPEC-GLC). FPEC-GLC profiles of the hydroxy acids showed peaks that were different for different serotypes and the FPEC-GLC carboxylic acid profiles differed from the control medium. These differences were reproducible when the same lot for medium was used. There were differences in profiles between lots of control media due apparently to different fetal bovine sera used in the growth medium. Therefore, the same lot of medium was necessary to reproduce profiles. The data obtained from the study indicate that FPEC-GLC can be used to detect changes in cellular metabolism caused by viral infection, and that these metabolic changes might be useful in detection of genetic differences in viruses as reflected by detectable changes in the metabolism of the infected cell.

Rapid differentiation of rocky mountain spotted fever from chickenpox, measles, and enterovirus infections and bacterial meningitis by frequency-pulsed electron capture gas-liquid chromatographic analysis of sera.

Normal sera and sera from patients with Rocky Mountain spotted fever, chickenpox, enterovirus infections, measles, and Neisseria meningitidis infections were extracted with organic solvents under acidic and basic conditions and then derivatized with trichloroethanol or heptafluorobutyric anhydride-ethanol to form electron-capturing derivatives of organic acids, alcohols, and amines. The derivatives were analyzed by frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). There were unique differences in the FPEC-GLC profiles of sera obtained from patients with these respective diseases. With Rocky Mountain spotted fever patients, typical profiles were detected as early as 1 day after onset of disease and before antibody could be detected in the serum. Rapid diagnosis of Rocky Mountain spotted fever by FPEC-GLC could permit early and effective therapy, thus preventing many deaths from this disease.

Frequency-pulsed electron capture gas-liquid chromatography and the tryptophan color test for rapid diagnosis of tuberculous and other forms of lymphocytic meningitis.

A total of 260 samples of cerebrospinal fluid received from Egypt, the United States, Canada, and South America were examined by frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC) for tuberculous and other forms of lymphocytic meningitis. Thirty-four of the specimens were culture positive for M. tuberculosis, and four cerebrospinal fluid specimens of herpes meningitis were established by immunological techniques. The compound, 3-(2'-ketohexyl)-indoline, was found in about 60% of the Egyptian tuberculous specimens and none of the culture-positive American specimens. the carboxylic and hydroxy acid FPEC-GLC profiles were used effectively in conjunction with other clinical data to make the diagnosis even in the absence of 3-(2'-ketohexyl)indoline. Herpes meningitis and mixed infections of Myeobacterium tuberculosis-herpes, M. tuberculosis-leptospira, and M. tuberculosis-Haemophilus influenzae produced profiles different from each other and from pure culture cases. The color test for tuberculous meningitis was evaluated, and free tryptophan was eliminated as the source of color reaction. Indications are that 3-(2'-ketohexyl)indoline, in most cases, is not responsible for the positive color reaction. Differences in the clinical and FPEC-GLC data obtained from samples from different geographical regions are discussed.

Rapid differentiation of the major causative agents of bacterial meningitis by use of frequency-pulsed electron capture gas-liquid chromatograph: analysis of acids.

The major causative agents of bacterial meningitis, Haemophilus influenzae serogroup B, Neisseria meningitidis serogroups B and C, Klebsiella pneumoniae, Streptococcus pneumoniae, and two types of Escherichia coli, were cultured in a modified chemically defined Catlin medium and in a commercial version of the unmodified Catlin medium. The spent media were extracted under acidic conditions, and electron-capturing derivatives were prepared by derivatization with trichloroethanol or haptafluorobutyric anhydride. The derivatives were analyzed on a gas chromatograph equipped with a frequency-pulsed electron capture detector and a PEP-2 computer. The data obtained from the study show that these organisms can be easily distinguished from each other on the basis of metabolic products detected in either type of medium. Three different metabolic groups were detected within two serogroups of N. meningitidis. The methods are practical, and the new technique should offer clinical laboratories and hospitals a better method for rapid identification of this important group of pathogens.

Rapid differentiation of the major causative agents of bacterial meningitis by use of frequency-pulsed electron capture gas-liquid chromatography: analysis of amines.

The major causative agents of bacterial meningitis (Haemophilus influenzae serogroup B, Neisseria meningitidis serogroups B and C, Klebsiella pneumoniae, Steptococcus pneumoniae, and two types of Escherichia coli) were cultured in a chemically defined medium, and selected strains were further studied in Todd-Hewitt medium. After acidic extraction of the spent media with chloroform, a basic extraction was made with chloroform to obtain amines. A third extraction was performed on re-acidified Todd-Hewitt medium with ethyl ether to obtain hydroxyacids. The extracts were derivatized with heptafluorobutyric anhydride-ethanol to form electron-capturing derivatives, and the derivatives were analyzed on a frequency-pulsed electron capture gas-liquid chromatograph (FPEC-GLC) equipped with a PEP-2 computer. The data obtained from the study showed that amines were produced by these organisms that formed characteristic patterns. Different serotypes of K. pneumoniae and the two serogroups of N. meningitidis produced different types of FPEC-GLC profiles within serotypes. E. coli produced several hydroxy acids on Todd-Hewitt medium that made it unique among the organisms studied. The methods used are practical and the techniques have potential for use in clinical laboratories and hospitals as a valuable aid for the rapid identification of the major causative agents of bacterial meningitis.

Electron capture gas-liquid chromatographic-mass spectral identification of acids produced by Neisseria meningitidis in a defined medium.

The acid metabolites and the cellular fatty acids of three strains of Neisseria meningitidis grown in a chemically defined liquid medium were determined with computerized frequency-pulsed electron capture gas-liquid chromatography. Five acids not previously reported were subsequently identified: isobutyric, octanoic, decenoic (C10:1), dodecenoic (C12:1), and tetradecenoic (C14:1). These acids were produced during active metabolism and were not detected as cellular constituents. The frequency-pulsed electron capture gas-liquid chromatography methods which we used provide a rapid, reliable, sensitive means of detecting both these and other metabolic and cellular acids in spent culture medium.

Possible use of frequency-pulse-modulated electron capture gas-liquid chromatography to identify septic and aseptic causes of pleural effusions.

Frequency-pulse-modulated electron capture gas-liquid chromatography was used in conjunction with appropriate derivatization procedures to obtain chromatograms from extracts of pleural effusions. These chromatograms were used to rapidly classify the various types of pleural effusions. With this method we have been able to distinguish among a limited number of effusions caused by congestive heart failure, Mycobacterium tuberculosis, and some other types of bacterial empyemas and pleural effusions.

Identification of some basic extractable compounds produced by Neisseria gonorrhoeae and Neisseria meningitidis in a defined medium.

Electron capture gas-liquid chromatography and mass spectrometry have been used to identify some of the basic extractable heptafluorobutyric anhydride reactive compounds found in a defined medium after 20 h of growth by Neisseria gonorrhoeae and N. meningitidis. Acetoin, 2,3-butanediol, pyrroline, and 1,3-diaminopropane were identified by both gas chromatography and mass spectrometry; 2-hydroxy-pyrrolidine and 3-aminomethyl-pyrrolidine were tentatively identified by mass spectrometry. A possible origin of the amines is through enzymatic oxidation of polyamines.

Electron capture gas chromatography detection and mass spectrum identification of 3-(2'-ketohexyl)indoline in spinal fluids of patients with tuberculous meningitis.

A basic, extractable, indolic type of compound, which was derivatized with heptafluorobutyric anhydride and pyridine, was obtained from the cerebrospinal fluids of patients with acute tuberculous meningitis. The compound was detected by frequency-pulsed, modulated electron capture gas-liquid chromatography, and it was tentatively identified by mass spectrometry as 3-(2'-ketohexyl)indoline. The compound was found to be valuable for differentiating between tuberculous, cryptococcal, and aseptic meningitides.

Electron capture gas chromatography study of the acid and alcohol products of Clostridium septicum and Clostridium chauvoei.

The metabolic products produced by several strains of Clostridium septicum obtained from patients and animals, along with strains of Clostridium chauvoei, were studied in chopped meat glucose medium by electron capture gas-liquid chromatography (EC-GLC). The strains of C. septicum and C. chauvoei were shown to comprise five different metabolic groups. Both the EC-GLC study and the O and H antigenic study performed previously showed that strains of C. septicum comprise a heterogeneous group. One type of metabolic profile was found only in strains of C. chauvoei. The O antigen types and EC-GLC metabolic types of C. septicum correlated fairly well in isolates from cancer patients but not in stock culture and animal isolates.