Background: Short-chain fatty acids such as lactic acid produced by the intestinal bacterial flora have various physiological actions involved in health, and it is important to determine the concentrations of faecal short-chain fatty acids and evaluate their relationship with large intestinal diseases. In this study, we evaluated the highly selective and sensitive simultaneous measurement of both volatile and non-volatile short-chain fatty acid hydrazides using high-performance liquid chromatography (HPLC). Materials and methods: Faeces treated with ethanol were used as analytic samples. Short-chain fatty acids were measured as fatty acid hydrazides by HPLC. Results: For 12 types of short-chain fatty acid, the results regarding linearity, recovery tests and reproducibility were favourable. Faeces treated with ethanol could be stored at room temperature. Discussion: The stability of short-chain fatty acids in faeces at room temperature was statistically analysed. Faeces stored without treatment with ethanol showed increases/decreases in the concentrations of short-chain fatty acids, which may be due to assimilation by intestinal bacteria. However, specimen in 70% ethanol and stored in room temperature exhibited no substantial changes in concentrations of short-chain fatty acids up to seven days.
We simultaneously quantified fecal bile acids (BAs) and short-chain fatty acids (SCFAs) florescence labeled with 9chloromethylanthracene using high-performance liquid chromatography-fluorescence (HPLC-FL) and developed an inexpensive and highly accurate method for determining the ratio of BAs and SCFAs in colorectal cancer patients and healthy controls. Samples were extracted with hexane/ether, and extractants were measured using HPLC-FL. The healthy subject group included 17 men and 21 women, whereas the colorectal cancer group included patients with cancer in the rectum (3 men, 2 women), sigmoid colon (3 men, 2 women), and ascending colon (2 men, 3 women). The contribution rate of determination for calibration curves was >0.99, and the additional recovery rate was 67.2%-107% for the simultaneous quantification of fecal BAs and SCFAs using HPLC-FL. Intra-day and inter-day variations in the control feces ranged 2.4%-5.1% and 3.1%-9.2%, respectively. The proportion of primary BAs to total BAs was higher in the colorectal cancer group (87.3%) than in the healthy subject group (67.9%). A significant difference was observed in the ratio of BAs to butyric acid between healthy subject and colorectal cancer groups. BA levels were higher in the colorectal cancer group. Thus, the ratio of total BAs to butyric acid may be a better predictor of colon cancer than BAs or SCFAs alone.
Serum sialic acid (SA) levels are important for diagnosis, follow-up, and mechanistic analysis of malignant diseases. However, little is known about the levels of SA bound to serum IgM. Here, we isolated IgM from sera of healthy individuals and patients with cancer using DEAE chromatography and 8% polyethylene glycol precipitation. In this fraction, which contained partially purified IgM (recovery; 52%; purity: 25%), SA was quantified with fluorescence detection-HPLC (detection limit: 0.08 μM). SA levels in the IgM-enriched fraction was significantly higher in cancer patients (104 ± 27 µM) than in healthy individuals (81 ± 11 µM; P = 0.003).
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