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1.  Improvement of lumbar bone mass after infliximab therapy in Crohn’s disease patients 
BACKGROUND:
Patients with Crohn’s disease (CD) have a high risk of developing osteoporosis, but the mechanisms underlying bone mass loss are unclear. Elevated proinflammatory cytokines, such as tumour necrosis factor-alpha (TNFα), have been implicated in the pathogenesis of bone resorption.
AIM:
To assess whether suppression of TNFα with infliximab treatment has a beneficial effect on lumbar bone mass.
METHODS:
Adult CD patients who had received infliximab treatment, and who underwent lumbar densitometric evaluation before and during treatment, were selected. Adult CD patients who had never received infliximab treatment were selected as controls. Information regarding age, sex, weight, duration of CD, use of glucocorticoids and bisphosphonates, and signs of disease activity between both densitometric measurements were collected.
RESULTS:
Data from 45 patients were analyzed. The control group (n=30, mean [± SD] 26.7±9 years of age) had a significantly higher increase in body weight between both evaluations (6.26%±8%) than the infliximab group (n=15, 30.6±13 years), which had an increase of 0.3%±7.4%. There was a strong correlation between the final weight and lumbar bone mineral content (BMC) in both groups. The infliximab group had a significant increase in lumbar bone area (4.15%±6.6%), BMC (12.8%±13.6%) and bone mineral density (8.13%±7.7%) between both evaluations (interval 22.6±11 months) compared with the control group. The increase in BMC in patients who had received infliximab treatment was significant when compared with control patients who had received glucocorticoids (n=8) or had evidence of disease activity (n=13).
CONCLUSION:
Infliximab therapy improved lumbar bone mass independent of nutritional status. This finding suggests that TNFα plays a role in bone loss in CD.
PMCID: PMC2658130  PMID: 17948133
Bone mass; Crohn’s disease; Infliximab; Osteopenia; Osteoporosis
2.  13C urea breath test for Helicobacter pylori: Evaluation of 10-minute breath collection 
AIM:
To determine whether a shortened 13C urea breath test (13C UBT) (breath collection time of 10 min) is as reliable as the standard assay (30 min).
METHODS:
Two hundred ninety-seven patients (mean ± SD: 53±16 years, 57% female) completed a 13C UBT. Breath samples were obtained at baseline and at 5 min intervals up to 30 min. Sixty-seven patients also underwent endoscopic biopsy. Cluster analysis was performed on the 13C UBT data to determine the optimal cut-off point at each time interval. Sensitivity and specificity of the 13C UBT at all intervals compared with histology and culture and against the standard 30 min interval were determined.
RESULTS:
The calculated optimal cut-off points for each time interval (T), expressed as delta over baseline (δ‰), were 3.29 δ‰ at T5, 3.15 δ‰ at T10, 3.42 δ‰ at T15, 3.17 δ‰ at T20, 2.99 δ‰ at T25 and 2.82 δ ‰ at T30. Except at T5, the risk of false-positive and false-negative test results at each time interval was lower than 2.3% using these cut-off points. When replacing the cut-off points with 3.0 δ‰, the risk of error was still lower than 2.3%. The test at T10 showed 98.6% sensitivity and 98.6% specificity compared with T30. T10 and T30 showed 100% sensitivity and 96% specificity compared with histology and culture.
CONCLUSIONS:
The 13C UBT is an accurate, noninvasive test, even when the breath sample interval is reduced to 10 min. The present study confirms the validity of a cut-off point of 3.0 δ‰ for the 10 min and 30 min 13C UBT.
PMCID: PMC2660834  PMID: 17171196
13C urea breath test; Cut-off point; Helicobacter pylori
3.  13C urea breath test for Helicobacter pylori: Determination of the optimal cut-off point in a Canadian community population 
AIM:
To determine the test characteristics and the optimal cut-off point for the 13C urea breath test (13C UBT) in a Canadian community laboratory setting.
METHODS:
Of 2232 patients (mean age ± SD: 51±21 years, 56% female) who completed a 13C UBT, 1209 were tested to evaluate the primary diagnosis of Helicobacter pylori infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the 13C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results. Additionally, 176 patients underwent endoscopic biopsy to allow validation of the sensitivity and specificity of the 13C UBT against histology and microbiology using the calculated cut-off point.
RESULTS:
The calculated cut-off points were 3.09 δ‰ for the whole study population (n=2232), 3.09 δ‰ for the diagnosis group (n=1209) and 2.88 δ‰ for the post-treatment group (n=1023). When replacing the calculated cut-off points by a practical cut-off point of 3.0 δ‰, the risk of false-positive and false-negative results was lower than 2.3%. The 13C UBT showed 100% sensitivity and 98.5% specificity compared with histology and microbiology (n=176) for the diagnosis of active H pylori infection.
CONCLUSIONS:
The 13C UBT is an accurate, noninvasive test for the diagnosis of H pylori infection and for confirmation of cure after eradication therapy. The present study confirms the validity of a cutoff point of 3.0 δ‰ for the 13C UBT when used in a large Canadian community population according to a standard protocol.
PMCID: PMC2660833  PMID: 17171195
13C urea breath test; Cut-off point; Helicobacter pylori

Results 1-3 (3)