Biomedical subjects
R Watts
Publications and source records attributed to R Watts.
Separation of mono- and diglycerides by gas--liquid chromatography.
The parameters affecting the separation and quantification of trimethylsilyl ethers of mono- and diglycerides have been investigated by gas-liquid chromatography with QF-1 and SE-30 as stationary phases and a flame ionization detector. Results have been compared with those obtained earlier for triglycerides. The isothermal characteristics of a range of trimethylsilyl ethers of mono- and diglycerides on both stationary phases showed that log retention volume was directly proportional to carbon number and inversely proportional to absolute temperature. However, glyceride derivatives with lower carbon numbers deviated from these relationships. By using various rates of programmed temperature rise, we have determined the elution temperatures (Kelvin scale) of the mono- and diglyceride trimethylsilyl ethers relative to that of glycerol trilaurate. The "carbon equivalent of a trimethylsilyl group" is defined and shown to be useful in comparing the chromatographic properties of different glyceride classes. Weight and molar correction factors have been obtained and used to analyze diglycerides derived from egg and bovine brain lecithins.
Gas-liquid chromatography of monoglycerides and diglycerides.
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Separation of triglycerides by gas-liquid chromatography.
The parameters affecting the separation and quantification of triglycerides by gas-liquid chromatography have been investigated with the use of QF-1 and SE-30 as stationary phases and a flame ionization detector. The isothermal characteristics of a wide variety of triglycerides (carbon number 6 to 60) on both columns show that long retention volume is directly proportional to carbon number and inversely proportional to absolute temperature. Isothermal retention indices of some triglycerides are given, as are column efficiencies (in terms of theoretical plates and ability to separate closely related triglycerides). When various rates of programmed temperature rise are used, retention indices have been found to be less useful than absolute or relative elution temperatures. The elution temperatures of triglycerides of carbon number 6 to 54 have been determined relative to that of trilaurin. Under optimal separation conditions weight and molar correction factors can be obtained. Triolein and tristearin have been partially separated, as have certain triglycerides that have the same carbon number but widely different fatty acids. The natural triglycerides of human milk fat have been separated.
Quantitative gas-liquid chromatographic analysis of rodent milk triglycerides.
A comparison has been made of the milk and adipose tissue triglycerides of rabbits and guinea pigs provided with one diet and of rats and mice provided with another. Both intact triglycerides and component fatty acids were analyzed by gas-liquid chromatography. Good correlation of the data obtained by the two techniques was obtained by calculating the average chain length of the fatty acid moieties. Little difference was found in the triglyceride composition of the adipose tissue of the different species. However, wide variation in the triglyceride composition of the milk was found between the species: the average fatty acid chain length in milk was 11.7 for rabbits, 14.2 for rats, 15.3 for mice, and 17.2 for guinea pigs. The corresponding values for adipose tissue were in the range 16.9-17.4 in all animals. The significance of enzymes that synthesize short-chain fatty acids in mammary gland is discussed.
Actinomycetoma masquerading as an abdominal neoplasm.
Despite the fact that infection accompanying actinomycotic organisms is relatively rare, the possibility of such infection should be kept in mind because the organism is known to be commensal in the oral cavity, lungs, and intestinal tract. Abdominal lesions may mimic a neoplasm in many ways--physical findings, clinical course, and roentgenographic changes. Since the bacterium is anaerobic and difficult to grow on culture, one may have to rely on histologic confirmation for diagnosis. The infection can usually be eradicated by large doses of antibiotic (penicillin) over an extended period of time.
Aortic washout of 125I compounds in atherosclerotic and normal rabbits.
An in vivo rabbit model is described for the study of aortic washout of 125I tagged compounds. Washout is compartmental and in sequence from the lumen, aortic wall, and periaortic fat. Toluene-azo-naphthol (TAN) affixed chiefly to periaortic fat. A double isotope method with TAN plus a cholesterophilic substance is suggested for the assay of atherosclerosis in situ.
Antibodies to lactate dehydrogenase of Plasmodium knowlesi are specific to Plasmodium species.
Polyclonal immune monkey serum raised against schizonts of Plasmodium knowlesi (H-strain) showed the presence of antibodies to lactate dehydrogenase (LDH) of P. knowlesi by immunodot enzyme staining method. The anti-LDH antibodies are most probably directed towards an epitope distinct from the catalytic site as shown by the specific enzyme staining of LDH after binding with antibody on nitrocellulose paper. These antibodies showed reactivity with LDH from different strains (H, P and W1 strains of P. knowlesi) and species (P. cynomolgi B, P. berghei, P. yoelii, P. falciparum and P. vivax) of malarial parasites but did not cross-react with three isoenzymic forms of mammalian LDH (A4, B4 and C4) as well as with LDH from some protozoan and helminth parasites. These findings suggest that the anti-LDH antibodies have defined specificity to Plasmodium spp.
Longitudinal analysis of antibodies to histones, Sm-D peptides and ubiquitin in the serum of patients with systemic lupus erythematosus, rheumatoid arthritis and tuberculosis.
A longitudinal analysis of 12 lupus patients has been undertaken to assess their autoantibody reactivity by ELISA with histones, Sm-D peptides, ubiquitin and DNA. As controls patients with rheumatoid arthritis and tuberculosis were studied. Whereas the control groups showed little evidence of autoantibody reactivity 25% or more of the lupus patients had raised levels of autoantibodies against eight of the nine antigens tested. Of particular note was the fact that approximately 70% of the blood tested possessed antibodies reacting with Sm-D peptide 1-20. In contrast only one patient had anti-Sm antibodies by counter immunoelectrophoresis. In general the levels of antibodies to core histones reflected disease activity unlike the levels of anti-H1 antibodies. High levels of antibodies to ubiquitin often seemed to correlate inversely with active lupus and DNA antibody levels.
Bacteremia of dental origin and antimicrobial sensitivity following oral surgical procedures in children.
METHODS: The prevalence and intensity of bacteremia of dental origin were examined in 207 children divided into four groups: a baseline with no surgical intervention (group I), after a single tooth extraction (group II), multiple tooth extraction (group III), and mucoperiosteal flap elevation (group IV). The bacterial isolates were grown using a broth culture (Bactec) and lysis centrifugation (Paediatric Isolator) techniques. Dental plaque deposits, gingivitis, spontaneous gingival bleeding and the presence/absence of a dental abscess were recorded and their relationship to bacteremia assessed. RESULTS: The broth culture was positive for group I 11% of the time, group II for 43%, group III for 54%, and group IV for 43%. The Paediatric Isolator system was found to be a poor method for detecting bacteremia, having only one quarter the sensitivity of the broth culture technique. When organisms were isolated, the intensity of bacteremia ranged from 1 to 3400 colony forming units per milliliter (cfu/mL). Bacterial isolates were susceptible to most of the antibiotics recommended for antibiotic prophylaxis, but erythromycin, gentamycin, penicillin G, and teicoplanin were only 80% (or less) effective in their efficacy while chlorhexidine, amoxicillin, clindamycin, and vancomycin were between 92 and 100% effective. CONCLUSIONS: The antibiotics commonly used for an oral and/or parenteral prophylaxis are likely to be effective on at least 80% of occasions with most of them effective on 100% of occasions.