Parasites in soil samples from Signy island, Antarctica

@#Studies on parasite populations in Antarctic soils are scarce and thus little is known about the threat of these parasites towards either the natural fauna or human visitors. However, human presence in Antarctica, mainly through research and tourism, keeps increasing over time, potentially exposing visitors to zoonotic infections from Antarctic wildlife and environment. Most available literature to date has focused on faecal samples from Antarctic vertebrates. Therefore, this study addressed the possible presence of parasites in Antarctic soil that may be infectious to humans. Soil samples were obtained from five locations on Signy Island (South Orkney Islands, maritime Antarctic), namely North Point and Gourlay Peninsula (penguin rookeries), Pumphouse (relic coal-powered pump house), Jane Col (barren high altitude fellfield) and Berntsen Point (low altitude vegetated fellfield close to current research station). Approximately 10% of the soil samples (14/135) from 3 out of the 5 study sites had parasites which included Diphyllobotridae spp. eggs, Cryptosporidium sp., an apicomplexan protozoa (gregarine), Toxoplasma gondii, helminths (a cestode, Tetrabothrius sp., and a nematode larva) and mites. The presence of parasites in the 3 sites are most likely due to the presence of animal and human activities as two of these sites are penguin rookeries (North Point and Gourlay Peninsula) while the third site (Pumphouse Lake) has human activity. While some of the parasite species found in the soil samples appear to be distinctive, there were also parasites such as Cryptosporidium and Toxoplasma gondii that have a global distribution and are potentially pathogenic.

Clinical and prognostic significance of serum transforming growth factor-beta1 levels in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has a poor 5-year survival rate of 5%. Biomarkers for the early detection of pancreatic cancer are urgently needed. Transforming growth factor-beta1 (TGF-β1) is elevated in the tissues and plasma of patients with PDAC. However, no studies systemically report prognostic significance of plasma TGF-β1 levels in PDAC. In the present study, we assessed the prognostic significance of serum TGF-β levels in patients with PDAC. TGF-β levels were determined in serum from 146 PDAC patients, and 58 patients with benign pancreatic conditions. Regression models were used to correlate TGF-β levels to gender, age, stage, class, and metastasis. Survival analyses were performed using multivariate Cox models. Serum levels of TGF-β1 distinguished PDAC from benign pancreatic conditions (P<0.001) and healthy control subjects (P<0.001). Serum levels of TGF-β also distinguished tumor stage (P=0.002) and lymph node metastasis (P=0.001). High serum levels of TGF-β1 were significantly correlated with reduced patient survival. Multivariate analysis revealed that TGF-β1, lymph node metastasis and tumor stage were independent factors for PDAC survival. Our results indicate that serum TGF-β1 may be used as a potential prognostic marker for PDAC.

A three-phase epidemiological study of short and long sleepers in a middle-aged Chinese population: prevalence and characteristics

Epidemiological studies of short and long sleepers have not been conducted previously. We collected socioeconomic, psychological, and polysomnographic characteristics of 6501 parents (3252 men and 3249 women) of 4036 primary school children in Guangzhou city. The study data were collected in three phases. The overall prevalence of short (5 h or less) and long (10 h or more) sleep duration was 0.52 and 0.64%, respectively. Long sleepers had higher Eysenck Personality Questionnaire neuroticism scores [odds ratio (OR)=1.224, 95% confidence interval (CI)=1.047-1.409] and lower education levels (OR=0.740, 95%CI=0.631-0.849) than short sleepers. In the polysomnographic assessment, short, long, and normal sleepers (7-8 h) shared similar durations of Stage 3 sleep (short=25.7±10.7, long=20.3±7.9, and normal=28.0±12.8 min, F=1.402, P=0.181). In daytime multiple sleep latency tests, short sleepers (10/19, 52.6%) were more prone to have a short sleep latency (≤8 min) than long sleepers (2/23, 8.7%). In addition to different sleep durations, neuroticism might also contribute to differences between short and long sleepers in social achievements. Stage 3 sleep might be essential for humans. The short sleep latency (≤8 min) of short sleepers in multiple sleep latency tests should be interpreted cautiously, since it was of the same severity as required for a diagnosis of narcolepsy or idiopathic hypersomnia.

Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries.

Growth inhibitory effect and Chk1-dependent signaling involved in G2/M arrest on human gastric cancer cells induced by diallyl disulfide

Diallyl disulfide (DADS) inhibits growth and induces cell cycle G2/M arrest in human gastric cancer MGC803 cells. In this study, 15 mg/L DADS exerted similar effects on growth and cell cycle arrest in human gastric cancer BGC823 cells. Due to the importance of cell cycle redistribution in DADS-mediated anti-carcinogenic effects, we investigated the role of checkpoint kinases (Chk1 and Chk2) during DADS-induced cell cycle arrest. We hypothesized that DADS could mediate G2/M phase arrest through either Chk1 or Chk2 signal transduction pathways. We demonstrated that DADS induced the accumulation of phosphorylated Chk1, but not of Chk2, and that DADS down-regulated Cdc25C and cyclin B1. The expression of mRNA and total protein for Chkl and Chk2 was unchanged. Chk1 is specifically phosphorylated by ATR (ATM-RAD3-related gene). Western blot analysis showed that phospho-ATR was activated by DADS. Taken together, these data suggest that cell cycle G2/M arrest, which was associated with accumulation of the phosphorylated forms of Chk1, but not of Chk2, was involved in the growth inhibition induced by DADS in the human gastric cancer cell line BGC823. Furthermore, the DADS-induced G2/M checkpoint response is mediated by Chk1 signaling through ATR/Chk1/Cdc25C/cyclin B1, and is independent of Chk2.

Genetic variations of EBV-LMP1 from nasopharyngeal carcinoma biopsies: potential loss of T cell epitopes

To find Epstein-Barr virus (EBV) strains with genetic variations of EBV latent membrane protein 1 (EBV-LMP1) from nasopharyngeal carcinoma (NPC), the full-length DNA of LMP1 genes from 21 NPC biopsies obtained in Hunan province in southern China was amplified and sequenced. Our sequences were compared to those previously reported by the Clustal V method. Results showed that all 21 sequences displayed two amino acid changes most frequently in LMP1 of CD4+ T cell epitopes at codons 144 (F arrow right I, 21/21) and 212 (G arrow right S, 19/21) or (G arrow right N, 2/21). We also show that type A EBV strain is prevalent in the cases of NPC from Hunan province with a 30-bp 18/21 deletion, and we highlight that this deletion resulted in loss of one of the CD4+ T cell-restricted epitopes. The other 3 sequences without this deletion all had a change at codon 344 (G arrow right D). Furthermore, in the major epitope sequence of CD8+ T cells restricted by HLA-A2, all 21 sequences showed changes at codons 126 (L arrow right F) and 129 (M arrow right I). Our study discovered that one of the 21 sequence variations harbored a new change at codon 131 (W arrow right C), and 5/21 specimens showed another novel change at codon 115 (G arrow right A) in the major epitope sequence of CD8+ T cells restricted by HLA-A2. Our study suggests that these sequence variations of NPC-derived LMP1 may lead to a potential escape from host cell immune recognition, protecting latent EBV infection and causing an increase in tumorigenicity.