With unmatched mass resolution, mass accuracy, and exceptional detection sensitivity, Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) has the potential to be a powerful new technique for high-throughput metabolomic analysis. In this study, we examine the properties of an ultrahigh-field 12-Tesla (12T) FTICR-MS for the identification and absolute quantitation of human plasma metabolites, and for the untargeted metabolic fingerprinting of inbredstrain mouse serum by direct infusion (DI). Using internal mass calibration (mass error ≤1 ppm), we determined the rational elemental compositions (incorporating unlimited C, H, N and O, and a maximum of two S, three P, two Na, and one K per formula) of approximately 250 out of 570 metabolite features detected in a 3-min infusion analysis of aqueous extract of human plasma, and were able to identify more than 100 metabolites. Using isotopically-labeled internal standards, we were able to obtain excellent calibration curves for the absolute quantitation of choline with subpmol sensitivity, using 500 times less sample than previous LC/MS analyses. Under optimized serum dilution conditions, chemical compounds spiked into mouse serum as metabolite mimics showed a linear response over a 600-fold concentration range. DI/FTICR-MS analysis of serum from 26 mice from 2 inbred strains, with and without acute trichloroethylene (TCE) treatment, gave a relative standard deviation (RSD) of 4.5%. Finally, we extended this method to the metabolomic fingerprinting of serum samples from 49 mice from 5 inbred strains involved in an acute alcohol toxicity study, using both positive and negative electrospray ionization (ESI). Using these samples, we demonstrated the utility of this method for high-throughput metabolomics, with more than 400
Bile cast nephropathy is a condition of renal dysfunction in the setting of hyperbilirubinemia. There are very few cases of this condition reported in the last decade and a lack of established treatment guidelines. While the exact etiology remains unknown, bile cast nephropathy is presumed to be secondary to multiple concurrent insults to the kidney including direct toxicity from bile acids, obstructive physiology from bile casts, and systemic hypoperfusion from vasodilation. Therapy directed at bilirubin reduction may improve renal function, but will likely need dialysis or plasmapheresis as well. We report our case of bile cast nephropathy and the therapeutic measures undertaken in a middle-aged male with chronic renal insufficiency that developed hyperbilirubinemia and drug-induced liver injury secondary to antibiotic use. He developed acute renal injury in the setting of rising bilirubin. He subsequently had a progressive decline in renal and hepatic function, requiring dialysis and plasmapheresis with some improvement, ultimately requiring transplantation.
Choline is an essential nutrient for humans that is used to synthesize membrane phospholipids and the neurotransmitter acetylcholine. Betaine, a metabolite of choline, functions as a methyl-group donor in the conversion of homocysteine to methionine, and is important for renal function. Accurate analysis of choline intake was previously not possible because the choline content of most foods was not known. Using new and recently published data on the concentrations of choline in common foods, we measured the choline content of diets consumed ad libitum by healthy adult volunteers housed in a clinical research center and compared these with estimates of choline intake derived from 3-d food records kept by subjects immediately before study enrollment. Mean choline intake in this subject population met or slightly exceeded the current Adequate Intake (AI) of 7 mg/(kg . d) set by the Institute of Medicine. Men and women consumed similar amounts of choline per day (8.4 and. 6.7 mg/kg, respectively; P = 0.11). Choline intakes estimated from the 3-d food records were significantly lower than this (when expressed as mg/kg, or as total mg, but not when normalized to energy intake), suggesting underreporting of food intake. Intake of betaine, which may spare choline utilization as a methyl-group donor, was 5.3 mg/(kg . d) in men and 4.7 mg/(kg . d) in women. Intake of folate, vitamin B-12, and methionine + cysteine, were similar and sufficient in all subjects. The current recommended AI for choline seems to be a good approximation of the actual intake of this nutrient.
Choline is an essential nutrient for humans and its availability during pregnancy is important for optimal fetal development. The Food and Nutrition Board of the Institute of Medicine in the United States of America has set the adequate choline intake during pregnancy at 450 mg/day. There is limited data available on normal plasma choline concentrations in pregnancy. Moreover, there are neither documented studies of choline intake among pregnant women in the Jamaican population nor of free plasma choline concentrations during pregnancy. Sixteen women presenting to the antenatal clinic of the University Hospital of the West Indies (UHWI) at 10-15 weeks of gestation were selected for this pilot study. A food frequency questionnaire was administered to estimate frequency of consumption of foods rich in choline. Fasting blood samples were collected by venepuncture and plasma assayed for choline using liquid chromatography electrospray ionization isotopic dilution mass spectrometry. Most of the women reported consumption of diets that delivered less than the recommended choline intake (mean +/- SEM, 278.5 +/- 28.9 mg). Mean plasma choline concentration was 8.4 +/- 0.4 micromol/L. This falls below the normal concentration (10 micromol/L) reported for individuals that are not pregnant and pregnant (14.5 micromol/L). The results of this study may be an indication that the choline included in the diet of pregnant women in Jamaica may not be adequate to meet both the needs of the mother and fetus and that further studies are warranted to determine clinical implications.
Statement of Problem:Tetrahydrozoline has been introduced as new gingival retraction agent but its clinical efficacy with widely used conventional retraction agents has not been tested.Purpose:The study was designed to clinically evaluate efficacy of newer retraction agent tetrahydrozoline with two widely used retraction systems i.e., Expasyl retraction system and medicated retraction cords on basis of amount of gingival retraction.Materials and Methods:30 subjects were selected according to inclusion and exclusion criteria. Maxillary Impressions were made with irreversible hydrocolloid for all subjects. Tray material was used for making the special tray. Latin Block Design was Used in the Study to avoid tissue fatigue. Retraction was done with aluminium chloride; Tetrahydrozoline and Expasyl according to Latin block design. Impressions were poured with die stone. Casts were retrieved and sections were made with die cutter. 3 mm thin slices were obtained. Each slice was used to measure the amount of retraction under stereomicroscope under 20x and images were transferred to image analyser.Results:The amount of gingival retraction obtained by using aluminium chloride as gingival retraction agent was maximum (148238.33 μm2) compared to tetrahydrozoline (140737.87 μm2) and Expasyl (67784.90 μm2).
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