Validity and cost comparison of ^(14)carbon urea breath test for diagnosis of H Pylori in dyspeptic patients

AIM： To validate and compare the cost of microdose ^14C urea breath test （UBT） with histology and rapid urease test for the diagnosis of H Py/ori. METHODS： Ninety-four consecutive patients with dyspeptic symptoms undergoing gastroscopy were enrolled. Gastric biopsies were taken for histology and rapid urease test. UBT was performed after gastroscopy by microdose ^14 urea capsules. Sensitivity, specificity and accuracy of UBT were calculated and compared with histology and rapid urease test. Cost comparison of these tests was also performed. RESULTS： H pylori was diagnosed by histology and rapid urease test in 66 （70%） and 61 （65%） patients, while ^14C UBT detected infection in 63 （67%）. Accuracy of UBT was 93% in comparison with histology while its positive and negative predictive values were 97% and 84%, respectively. Comparison of ^14C UBT with rapid urease test gives an accuracy of 96%, with positive and negative predictive values of 95% and 97%, respectively. These results were highly reproducible with a Kappa test （P value 〈 0.001）. Cost of histology or rapid urease test with gastroscopy was 110 USD or 95 USD respectively while the cost of UBT was 15 USD.CONCLUSION： Microdose ^14C UBT was comparable to histology and rapid urease test. ^14C UBT is an economical, self sufficient and suitable test to diagnose active Hpylori infection in less developed countries.

Is lithium potentially a trace element?

Lithium, a naturally occurring element, is widely used in clinical settings for psychiatric treatment. Several studies showed that micro-dose lithium(e.g., lithium in drinking water) could have anti-aging and anti-dementia effects in addition to an anti-suicidal effect, although antimania and psychosis or anti-cancer effects are yet to be determined. Although these studies do not provide conclusive evidence, further studies are warranted to investigate whether lithium is trace element. If so, future studies would need to determine what levels are required to maintain mental health.

Microdosing cocktail study on the determination and pharmacokinetics of six hepatic cytochrome probes and their metabolites in rat

OBJECTIVE To describe a highly sensitive LC-ESI MSnmethod that was developed to simultaneously detect six CYP isoform-specific probes and their metabolites in rat plasma for microdosing cocktail study.METHODS After administration of a mixture of six probes(i.e.,a cocktail approach with caffeine 100μg·kg-1,tolbutamide100μg·kg-1,omeprazole 500μg·kg-1,dextromethorphan 500μg·kg-1,chlorzoxazone 50μg·kg-1and midazolam 100μg·kg-1)to SD rats.The plasma samples were extracted using ethyl acetate with diazepam and gliclazide as the IS.The assay was performed on an Agilent Eclipse Plus C18 column(2.1×50 mm,3.5μm).The mobile phase consisted of 0.01%formic acid(1 mmol·L-1ammonium formate)and acetonitrile.The flow rate was0.3 m L·min-1.The samples were analyzed by LC-20A&5500Qtrap ESI MSnin MRM mode.The MS/MS reaction selected 181.2/124.0 m/z ions for caffeine,195.2/138.2m/z for paraxanthine,269.1/170.0 m/z for tolbutamide,285.1/186.0 m/z for 4-hydroxytolbutamide,346.1/198.1m/z for omeprazole,362.2/214.2 m/z for 5-hydroxyomeprazole,272.3/147.1 m/z for dextromethorphan,258.2/157.0 m/z for dextrorphan,168.1/132.1 m/z for chlorzoxazone,326.1/291.2 m/z for midazolam,and 342.1/324.2m/z for 1′-hydroxymidazolam.RESULTS The datashowed that the method was with good linearity in the range of 0.2-200 ng·m L-1for caffeine,0.1-25 ng·m L-1for paraxanthine,0.05-100 ng·m L-1for omeprazole,0.01-25 ng·mL-1for 5-hydroxyomeprazole,0.1-200 ng·mL-1for dextromethorphan,0.05-12.5 ng·mL-1for dextrophan,0.2-200 ng·mL-1for midazolam,and 0.2-25 ng·mL-1for 1′-hydroxymidazolam,respectively.The stability%RSD for al probes was less than 15%and matrix effects in plasma on the ionization were negligible.CONCLUSION This highly sensitive and quantitative method allowed a pharmacokinetic study in subjects receiving doses 10-100 times lower than typical therapeutic doses.The established LCMS/MS method was suitable for pharmacokinetic study of this mixture cocktail probe group and could be applied deeply to CYP isoforms(1A2,2C9,2C19,2D6,2E1and 3A)research.