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Biomedical subjects

S W Page

Publications and source records attributed to S W Page.

At least 19 recordsLinked to original sources
PubMed1991

Identification of minor C18 triene and conjugated diene isomers in hydrogenated soybean oil and margarine by GC-MI-FT-IR spectroscopy.

Vegetable oils are partially hydrogenated in order to produce palatable products of suitable plasticity. The constituents of these new dietary products are complex mixtures of fatty acid isomers with different nutritional properties. A rapid method is described for separating and identifying fatty acid methyl ester (FAME) isomers of linolenic (octadecatrienoic, 18:3) acid and of conjugated octadecadienoic (18:2) acid, minor species found in hydrogenated soybean oil and margarine, by capillary gas chromatography-matrix isolation-Fourier transform-infrared (GC-MI-FT-IR) spectroscopy. FAMEs of 18:3 acid isomers in margarine, soybean oil hydrogenated in our laboratory, and isomerized linolenic acid were identified by this method, and MI-FT-IR spectra of FAME geometric isomers of octadecatrienoic and conjugated octadecadienoic acids are reported for the first time. Five major C18 triene GC peaks are found in chromatograms of isomerized methyl linolenate, representing species with tri-cis and tri-trans configurations and three species with cis-trans mixed configurations. FAME isomers with these configurations are also found for a hydrogenated soybean oil having an iodine value of 111. Methyl linolenate (tri-cis) is no longer found when soybean oil is further hydrogenated to an iodine value of 96. IR spectra characteristic of a tri-trans isomer are obtained for two test samples with iodine values of 111 and 96. Besides methyl linolenate, only isomers with a mono-trans di-cis configuration are found for the margarine analyzed. Conjugated cis-trans and trans-trans 18:2 FAME isomers are also found in all the hydrogenated soybean oil and margarine analyzed.

Chromatography, Gas↗
PubMed1991

Diethylstilboestrol--historical background and current regulatory status.

Diethylstilboestrol is a non-steroidal orally active oestrogen that in the past has been widely used in a variety of conditions in both medical and veterinary fields. In recognition of potential systemic availability to man of DES in the tissues of treated food-producing animals, together with an understanding of the potential teratogenic and carcinogenic toxicity of DES in man, the veterinary use of DES has been restricted to oral use in small animals only. Use of DES is prohibited in all food-producing animals.

Animals↗
PubMed1991

Diethylstilboestrol--clinical pharmacology and alternatives in small animal practice.

Diethylstilboestrol is currently only available in Australia for oral use in dogs and cats. As an orally and systemically active non-steroidal oestrogen, DES has been widely used in small animal veterinary medicine for a variety of indications. A review of the literature reveals that many of the recommendations for use are founded on anecdotal or unreported clinical observations. While many of the uses may be valid, accurate determinations of optimum dosing regimens have not been defined. This is especially unfortunate in view of the potential toxicity of DES to small animals. Nevertheless, particularly in cases of low-dose intermittent administration, oral DES appears indicated at least until data on alternative safe and effective interventions become available.

Animals↗
PubMed1991

Chloramphenicol 1. Hazards of use and the current regulatory environment.

Chloramphenicol is a broad-spectrum antibiotic which has enjoyed extensive use in both medical and veterinary practice. Shortly after its introduction in the late 1940s, the use of chloramphenicol was associated with the induction of an idiosyncratic form of aplastic anaemia in man. This rare and unpredictable adverse effect has since been associated not only with systemic use but with topical applications, as well as occupational exposure. Recognition of the small risk of a potentially fatal adverse reaction, together with the risk of selection of chloramphenicol-resistant pathogens, has led to restrictions on the veterinary uses of chloramphenicol. In Australia at present, the use of chloramphenicol is only permitted in small animals. Its use is specifically prohibited in food-producing animals, including horses.

Agricultural Workers' Diseases↗
PubMed1991

Chloramphenicol 3. Clinical pharmacology of systemic use in the horse.

The use of chloramphenicol in the horse is now prohibited as horses are classified as food-producing animals. However, chloramphenicol has until recently been widely available for oral, intramuscular or intravenous administration. A critical appraisal of the published literature on the use of chloramphenicol in the horse clearly demonstrates that there are sound pharmacokinetic and microbiological reasons for concluding that chloramphenicol is not an appropriate antibiotic for systemic use. The short half-life of chloramphenicol in the horse, together with the broad range of minimum inhibitory concentrations of target pathogens, preclude the use of practical dosage regimens. It can be concluded that the withdrawal of chloramphenicol will have no adverse effects on chemotherapy in the horse.

Animals↗
PubMed1991

Environmental pathology. Mast cell and eosinophil infiltration in intestinal mucosa of Lewis rats treated with L-tryptophan implicated in human eosinophilia myalgia syndrome.

A recently developed animal model for the L-tryptophan-associated eosinophilia myalgia syndrome was used to examine the small intestine and colon, because there is clinical involvement at these sites in patients. Increased perivascular inflammatory infiltrates rich in degranulating mast cells, eosinophils, and monocytes were seen in the lamina propria of experimental animals when compared with controls. L-Tryptophan-associated disease also shares many clinical features with idiopathic scleroderma/eosinophilic fasciitis, in which there is gastrointestinal involvement as well. These features are similar to those found in the recently described animal model. The apparent morphologic and clinical similarities between these entities suggest that the animal model is suitable for further studying the pathogenesis of the gastrointestinal involvement in all these diseases.

Animals↗
PubMed1990

L-tryptophan implicated in human eosinophilia-myalgia syndrome causes fasciitis and perimyositis in the Lewis rat.

Tryptophan-associated eosinophilia-myalgia syndrome (L-TRP-EMS) is a newly described syndrome which occurred in epidemic fashion in the United States in the summer and fall of 1989. Epidemiologic data has linked the syndrome to intake of L-tryptophan (L-TRP) from one specific manufacturer, but the precise etiologic compound(s) must be established by replication of the syndrome in an appropriate animal model. In this study, implicated L-TRP, United States Pharmacopeia (USP) grade L-TRP, or vehicle was administered by gavage in a blinded fashion for 38 d to female Lewis rats at doses comparable with those ingested by patients who developed the eosinophilia-myalgia syndrome. Animals receiving implicated L-TRP, but not those receiving USP grade L-TRP or vehicle, developed histologic signs consistent with fasciitis and perimyositis, specific pathologic features of human L-TRP-EMS. Peripheral blood eosinophilia was not observed. Hypothalamic corticotropin releasing hormone mRNA levels were lower and plasma corticosterone levels tended to be lower in the animals that received implicated L-TRP. Plasma L-kynurenine was higher in both L-TRP-treated groups compared to the vehicle-treated animals. The female Lewis rat is known to be susceptible to a wide variety of inflammatory diseases. Identification of specific inflammatory changes in this rat following exposure to implicated L-TRP indicates that this animal model will be important in subsequent investigations into the etiology, pathogenesis, and treatment of human L-TRP-EMS.

Animals↗
PubMedDate not supplied

Mutagenic perylenequinone metabolites of Alternaria alternata: altertoxins I, II, and III.

The mold genus Alternaria is a widely distributed plant pathogen. Some of these species, e.g., A. alternata, are common decay organisms of fruits and vegetables. Two novel perylene oxide metabolites, altertoxins II and III, have been identified in extracts of A. alternata isolates that exhibit mutagenic responses in the Ames Salmonella typhimurium assay. These identifications were based on mass, optical rotational, and 1H- and 13C-nmr spectral studies. Previous reports of related perylene dione mycotoxins have been clarified.

Alternaria↗
PubMedDate not supplied

Immunoaffinity column coupled with solution fluorometry or liquid chromatography postcolumn derivatization for determination of aflatoxins in corn, peanuts, and peanut butter: collaborative study.

An AOAC/IUPAC (International Union of Pure and Applied Chemistry) collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column for the determination of aflatoxin. The test portion is extracted with methanol-water (7 + 3), filtered, diluted to less than 30% methanol with water, and applied to the affinity column. The column is washed with water and the concentrated aflatoxins are eluted with methanol. Total aflatoxins are determined by solution fluorometry with bromine (SFB), and individual toxins are determined by reverse-phase liquid chromatography with postcolumn derivatization with iodine (PCD). Corn naturally contaminated with aflatoxins, and peanuts, peanut butter, and corn containing added aflatoxins (B1:B2:G1:G2 = 7:1:3:1) were sent to 24 collaborators in the United States, France, Canada, and the Republic of South Africa. Twelve collaborators used the SFB method, 9 used the PCD method, and 3 used both SFB and PCD methods. Twenty collaborators completed the study (10 used the SFB method, 7 used the PCD method, and 3 used both SFB and PCD methods). Test portions were spiked at 10, 20, and 30 ng/g. For SFB analyses, recoveries of total aflatoxins were 123, 105, and 107%, respectively; the relative standard deviation for repeatability (RSDr) ranged from 11.75 to 16.57%, and the relative standard deviation for reproducibility (RSDR) ranged from 10.97 to 33.09%. For PCD analyses, recoveries were 81, 81, and 83%, respectively; the RSDr ranged from 5.20 to 17.22%, and the RSDR ranged from 4.68 to 50.77%. The RSDr for aflatoxins B1 and G1 for spiked test portions ranged from 5.45 to 23.55%, and the RSDR ranged from 4.21 to 57.28%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗
PubMedDate not supplied

Enzyme-linked immunosorbent assay for screening aflatoxin B1 in cottonseed products and mixed feed: collaborative study.

A joint AOAC/IUPAC (International Union of Pure and Applied Chemistry) interlaboratory study of an enzyme-linked immunosorbent screening assay (ELISA) for aflatoxins was conducted in laboratories in Canada, France, Japan, South Africa, Switzerland, The Netherlands, Tunisia, and the United States. Twenty-eight samples of raw and roasted peanuts, corn, whole cottonseed, cottonseed meal, ammoniated cottonseed meal, and poultry feed containing various quantities of natural aflatoxins and supplemented when appropriate with aflatoxin B1 were distributed to participating laboratories for testing. The assay is based on conjugation of pure aflatoxin B1 to an enzyme and the competition between this conjugate and (free) aflatoxins in the product for aflatoxin-specific antibodies coated onto microtiter well walls. After a wash step to remove all unbound aflatoxins, a substrate, added to each well, is catalyzed from a colorless to a green solution by any bound enzyme-conjugated aflatoxin B1 present. The intensity of the color decreases as the amount of free aflatoxin B1 in the product increases. Overall correlation was good between ELISA and thin-layer chromatographic (TLC) results for cottonseed products and mixed feed. Variable results were reported for corn and peanut product samples. Although some positive samples (greater than 15 ng/g) of cottonseed products and mixed feed were reported to contain less than 15 ng/g by visual determination, a review of data for absorbance measurements showed that the contamination level was close to the greater than or equal to 15 ng/g standard and would not have been reported as negative under routine screening.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxin B1↗
PubMedDate not supplied

Liquid chromatographic methodology for the characterization of orange juice.

Liquid chromatographic (LC) methodology potentially useful for the characterization of orange juice, with particular regard to detecting adulteration of orange juice by computer pattern recognition analysis, has been developed. After dilution with methanol the juice is extracted with hexane to remove the carotenoids, which are chromatographed on a C18 column with an acetonitrile-methanol-methylene chloride mobile phase and detection at 450 nm. Further extraction of the juice with methylene chloride isolates the methoxylated flavones, which are chromatographed by reverse phase LC with an acetonitrile-methanol-water mobile phase and detection at 280 nm. The flavanone glycosides remaining in solution are chromatographed on a C18 column with an acetonitrile-water mobile phase and detection at 280 nm. The precisions of the heights of the 32 LC peaks selected for pattern recognition analysis were determined from 5 replicate analyses of a single juice. Coefficients of variation of the replicates ranged from 0.3 to 4.5%, with an average of 2.1%. Adulteration of products with sodium benzoate-fortified pulpwash or grapefruit juice can be detected by this method. Pattern recognition analysis of the data obtained for 80 authentic and 19 adulterated orange juices showed that the method is potentially useful for distinguishing between authentic and adulterated products.

Beverages↗