The Role of Fecal Occult Blood Test in Screening of Colorectal Cancer and Inflammatory Bowel Disease

Colorectal cancer (CRC) and inflammatory bowel disease (IBD) are a quite common colon disease in the world. The World Gastroenterology Organization (WGO) recommends screening test to detect colorectal cancer, i.e. fecal occult blood test (FOBT) and colonoscopy. Diagnosis of CRC is established based on a good history taking, clinical manifestation, physical examination and laboratory examination. Other supporting laboratory tests include routine laboratory test of hemoglobin for detecting anemia, examination of bleeding stool either macroscopically or microscopically. Radiographic examination, either colon in loop or colonoscopy (if such modalities are available), shall be performed to confirm the occurrence of cancer mass in the colon. Moreover, biopsy examination is carried out to obtain the histopathological feature of tumor mass or the type of cancers. WGO has made a guideline for CRC screening, which consists of 6 cascades, which depend on the risk of colorectal cancer and local facilities available. There are several kinds of FOBT, but the most frequently used include three methods, i.e.: the FOBT guaiac base/traditional, the fecal immunochemical test (FIT) and the FOB + transferrin rapid test (OT 102c & OT 103c). FIT and FOB + transferrin rapid test have a quite high sensitivity and specificity in detecting the lower gastrointestinal tract bleeding caused by colorectal cancer and IBD

Testing Luminescence Dating Methods for Small Samples from Very Young Fluvial Deposits

The impetus behind this study is to understand the sedimentological dynamics of very young fluvial systems in the Amazon River catchment and relate these to land use change and modern analogue studies of tidal rhythmites in the geologic record. Initial quartz optically stimulated luminescence (OSL) dating feasibility studies have concentrated on spit and bar deposits in the Rio Tapajós. Many of these features have an appearance of freshly deposited pristine sand, and these observations and information from anecdotal evidence and LandSat imagery suggest an apparent decadal stability. The characteristics of OSL from small (~5 cm) sub-samples from ~65 cm by ~2 cm diameter vertical cores are quite remarkable. Signals from medium-sized aliquots (5 mm diameter) exhibit very high specific luminescence sensitivity, have excellent dose recovery and recycling, essentially independent of preheat, and show minimal heat transfer even at the highest preheats. These characteristics enable measurement of very small signals with reasonable precision and, using modified single-aliquot regenerative-dose (SAR) approaches, equivalent doses as low as ~4 mGy can be obtained. Significant recuperation is observed for samples from two of the study sites and, in these instances, either the acceptance threshold was increased or growth curves were forced through the origin; recuperation is considered most likely to be a measurement artefact given the very small size of natural signals. Dose rates calculated from combined inductively coupled plasma mass spectrometry/inductively coupled plasma optical emission spectrometry (ICP-MS/ICP-OES) and high-resolution gamma spectrometry range from ~0.3 to 0.5 mGya−1 , and OSL ages for features so far investigated range from 13 to 34 years to several 100 years. Sampled sands are rich in quartz and yields of 212–250 µm or 250–310 µm grains indicate high-resolution sampling at 1–2 cm intervals is possible. Despite the use of medium-sized aliquots to ensure the recovery of very dim natural OSL signals, these results demonstrate the potential of OSL for studying very young active fluvial processes in these settings