Human fetal intestinal epithelial cells metabolize and incorporate branched chain fatty acids in a structure specific manner.

BACKGROUND: Branched chain fatty acids (BCFA) are constituents of gastrointestinal (GI) tract in healthy newborn human infants, reduce the incidence of necrotizing enterocolitis (NEC) in a neonatal rat model, and are incorporated into small intestine cellular lipids in vivo. We hypothesize that BCFA are taken up, metabolized and incorporated into human fetal cells in vitro. METHODS: Human H4 cells, a fetal non-transformed primary small intestine cell line, were incubated with albumin-bound non-esterified anteiso-17:0, iso-16:0, iso-18:0 and/or iso-20:0, and FA profiles in lipid fractions were analyzed. RESULTS: All BCFA were readily incorporated as major constituents of cellular lipids. Anteiso-17:0 was preferentially taken up, and was most effective among BCFA tested in displacing normal (n-) FA. The iso BCFA were preferred in reverse order of chain length, with iso-20:0 appearing at lowest level. BCFA incorporation in phospholipids (PL) followed the same order of preference, accumulating 42% of FA as BCFA with no overt morphological signs of cell death. Though cholesterol esters (CE) are at low cellular concentration among lipid classes examined, CE had the greatest affinity for BCFA, accumulating 65% of FA as BCFA. BCFA most effectively displaced lower saturated FA. Iso-16:0, iso-18:0 and anteiso-17:0 were both elongated and chain shortened by ±C2. Iso-20:0 was chain shortened to iso-18:0 and iso-16:0 but not elongated. CONCLUSIONS: Nontransformed human fetal intestinal epithelial cells incorporate high levels of BCFA when they are available and metabolize them in a structure specific manner. These findings imply that specific pathways for handling BCFA are present in the lumen-facing cells of the human fetal GI tract that is exposed to vernix-derived BCFA in late gestation.

[Analysis on factors associated with taking subsequent confirmation test among men who have sex with men after being tested positive in oral fluid HIV antibody test in Beijing].

OBJECTIVE: To analyze the proportion and associated factors of taking subsequent confirmation test among men who have sex with men (MSM) after being tested positive in oral fluid HIV antibody test. METHODS: By using successive sampling, 1 003 MSM, who were tested positive in oral fluid HIV antibody test in China-Bill & Melinda Gates Foundation AIDS prevention Program (Extension program) in Beijing during May 1 to December 31, 2013, were recruited. The inclusion criteria included: the objects were men who reported having sex with men; the objects aged more than 18 years old; the objects were tested positive in oral fluid HIV antibody test; the objects had not been reported as HIV positives in China Information System for Disease Control and Prevention previously. According to the program strategy, MSM grassroots organizations transferred the respondents to seek subsequent confirmation tests in specific Center for Disease Control and Prevention (CDCs) or hospitals. The subsequent confirmation tests included: fingertip blood HIV antibody rapid test, venous blood Enzyme Linked Immunosorbent Assay (ELISA) HIV antibody test and venous blood Western Blot (WB) HIV antibody test. Chi-square test was adopted to compare the proportion of taking subsequent confirmation tests in different groups. Nonconditional multivaritae binarylogistic regression analysis was taken to identify the associated factors with whether taking subsequent confirmation tests and to calculate the OR (95% CI) values. RESULTS: The 1 003 respondents were (30.9 ± 9.1) years old. Among all objects, 87.8% (881/1 003) of them took fingertip blood HIV antibody rapid tests and the positive rate was 85.4% (752/881). 98.0% (737/752) of those who were identified as positive in fingertip blood HIV rapid tests took ELISA and WB tests, and the positive rate was 94.4% (696/737). Comparing with those who were expected to seek subsequent confirmation tests in CDCs, the OR (95% CI) value of those who were expected to seek tests in hospitals was 5.10 (1.69-15.36). The OR (95% CI) values of those who used condom sometimes and those who never used condom in anal sex were 5.81 (2.14-15.77) and 3.45 (2.00-5.97) respectively, in comparison with those who reported not having anal sex or using condom consistently in anal sex during the past 6 months. Comparing with the respondents recruited from the internet, the OR (95% CI) values of those recruited in bathrooms, parks/toilets and bars were 0.17 (0.05-0.53), 0.10 (0.04-0.29) and 0.22 (0.06-0.79) respectively. The likelihood of taking subsequent confirmation test decreased with the increase of number of male sexual partners in the past 3 months, and the OR (95% CI) value was 0.92 (0.86-0.99). CONCLUSION: The potential HIV positive MSM in the bathroom, park/toilet and bars are less likely to take subsequent confirmation test. Those who do not use condom consistently during anal sex are more likely to seek subsequent confirmation test. Medical organization conducting subsequent confirmation tests is more likely to increase the confirmation test rate of potential HIV positive MSM. The number of male sexual partners has negative correlation with whether to accept the subsequent confirmation test.

Phylogenetic and temporal dynamics of human immunodeficiency virus type 1B in China: four types of B strains circulate in China.

To investigate the origin and evolutionary history of the spread of HIV-1 subtype B in China, a total of 409 sequences of pol gene sampled from 1994 to 2012 in 29 provinces across China was subjected to phylogenetic and Bayesian molecular clock analyses. The study reveals that subtype B strains in China are genetically diverse and can be classified into four distinct subgroups, namely B' (Thai-B), BJ-B (Beijing-B), Pan-B (Pandemic-B), and TW-B (Taiwan-B), according to the origin of the sequences. The BJ-B and TW-B are reported for the first time. Phylogeographic analysis reveals that B' exhibits a nationwide, transprovincial distribution, and is found in 21 provinces in China in this study, whereas the Pan-B, BJ-B, and TW-B lineages are restricted to particular regions. From the same common ancestor of B', there arise two subclusters in which sequences from Yunnan occupy the basal position. The times of the most recent common ancestors (tMRCAs) of B' and BJ-B are estimated to be 1983.6 (1975.9-1990.3) and 1995.3 (1989.6-2000.3), respectively. The skyline plot profile reveals an exponential decrease in median number of effective infections of subtype B in China from 1994 to 2009. The existence of four types of B clades also indicates distinct transmission networks of subtype B, originating from different introduction events at different time points. The data presented here offer a new perspective on the epidemic of HIV-1 subtype B in China.

Quantitative determination of compounds in tobacco essential oils by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.

A quantitative analysis of the individual compounds in tobacco essential oils is performed by comprehensive two-dimensional gas chromatography (GC x GC) combined with flame ionization detector (FID). A time-of-flight mass spectrometer (TOF/MS) was coupled to GC x GC for the identification of the resolved peaks. The response of a flame ionization detector to different compound classes was calibrated using multiple internal standards. In total, 172 compounds were identified with good match and 61 compounds with high probability value were reliably quantified. For comparative purposes, the essential oil sample was also quantified by one-dimensional gas chromatography-mass spectrometry (GC/MS) with multiple internal standards method. The results showed that there was close agreement between the two analysis methods when the peak purity and match quality in one-dimensional GC/MS are high enough.