Hypoxia inducible factors in cancer stem cells

Oxygen is an essential regulator of cellular metabolism, survival, and proliferation. Cellular responses to oxygen levels are monitored, in part, by the transcriptional activity of the hypoxia inducible factors (HIFs). Under hypoxia, HIFs regulate a variety of pro-angiogenic and pro-glycolysis pathways. In solid cancers, regions of hypoxia are commonly present throughout the tissue because of the chaotic vascular architecture and regions of necrosis. In these regions, the hypoxic state fluctuates in a spatial and temporal manner. Transient hypoxic cycling causes an increase in the activity of the HIF proteins above what is typical for non-pathologic tissue. The extent of hypoxia strongly correlates to poor patient survival, therapeutic resistance and an aggressive tumour phenotype, but the full contribution of hypoxia and the HIFs to tumour biology is an area of active investigation. Recent reports link resistance to conventional therapies and the metastatic potential to a stem-like tumour population, termed cancer stem cells (CSCs). We and others have shown that within brain tumours CSCs reside in two niches, a perivascular location and the surrounding necrotic tissue. Restricted oxygen conditions increase the CSC fraction and promote acquisition of a stem-like state. Cancer stem cells are critically dependant on the HIFs for survival, self-renewal, and tumour growth. These observations and those from normal stem cell biology provide a new mechanistic explanation for the contribution of hypoxia to malignancy. Further, the presence of hypoxia in tumours may present challenges for therapy because of the promotion of CSC phenotypes even upon successful killing of CSCs. The current experimental evidence suggests that CSCs are plastic cell states governed by microenvironmental conditions, such as hypoxia, that may be critical for the development of new therapies targeted to disrupt the microenvironment.

Hydrodynamic conditions in designed spiral photobioreactors

In this work, a series of spiral tube PBRs were introduced. Flow dynamics of microalgae fluid, light intensity histories of tracked cells and swirl numbers within the spiral PBRs were numerically simulated. Results show that strong swirl motions are formed in the cross-sections along axial coordinate of spiral PBRs, but no such vortice is observed for tubular PBR. The light intensity histories identify that the microalgae cells experience the so-called light/dark cycle, which is necessary to their growth. With high swirl numbers ranging from 0.15 to 0.35, the mixing performances of the spiral tube PBRs are much better than that of tubular PBR, indicating such innovative geometries of spiral tube PBRs may be applicable for large scale commercial cultivation of microalgae in the future.

Flocculation properties of a bioflocculant produced by Bacillus licheniformis

Studies of the flocculation properties of bioflocculant combined with its structure characterization are helpful to develop more effective bioflocculant. This paper reports findings of our research on the flocculation properties of the bioflocculant ZS-7 in the kaolin suspension based on its structure characterization. With the addition of 2 mg/L ZS-7 and 9 mM CaCl(2), the optimum temperature for flocculation performance of ZS-7 in the kaolin suspension is about 30°C, giving the highest flocculating activity 99.2%. Studies of the flocculation properties revealed that it was stable at 60-100°C and pH 4-10. Moreover, it could flocculate a kaolin suspension over a wide range of pH (2-12) and temperatures (4-95°C) in the presence of CaCl(2).

Pseudomonas aeruginosa serological analysis in young children with cystic fibrosis diagnosed through newborn screening

BACKGROUND

With newborn screening (NBS) for cystic fibrosis (CF), eradication of Pseudomonas aeruginosa (PA) is possible if PA detection occurs early. A serological response to infection likely precedes culture positivity in CF patients, so PA serological testing is very appealing in this population. However, controversies continue to exist about serology testing, titer cutoffs for enzyme-linked immunosorbent assay (ELISA) antibody tests, and their value in children with CF.

METHODS

This longitudinal, prospective study collected respiratory secretions as oropharyngeal swabs or expectorated sputum for culture and also sera over 6 years in 69 patients diagnosed by NBS. Serology assessed PA antibody titers against cell lysate, exotoxin A, and elastase. A novel statistical approach with weighted receiver operating characteristic (ROC) curves was used to determine best antibody titer cutoff values to predict subsequent PA positive cultures.

RESULTS

Using these weighted ROC curves, the order of sensitivity was found to be cell lysate, exotoxin A, and then elastase while age-specific cutoffs were better than fixed cutoffs previously used. Age-specific serological cutoffs both predict and detect PA respiratory infections with a higher sensitivity and specificity. Serological responses to the PA antigens determined that a response to cell lysate occurs significantly earlier than culture positivity.

CONCLUSIONS

Age-specific serological cutoffs rather than fixed values against common PA antigens improve early PA identification in infants and young children diagnosed with NBS. Regular serological assessment with age-specific cutoffs in these children appears to be a worthy diagnostic tool.

A novel HLA-B*37 allele, B*370105, was identified in a Chinese Han individual

We report here the sequence of a novel human leukocyte antigen B*37 allele, B*370105, which is identical to B*370101 except for a single nucleotide substitution in exon 3 at nucleotide 558 where C>A, codon 162 GGC>GGA, no coding change.

A novel HLA-DRB1 allele, DRB1*112802, was identified in a Chinese individual

We report here a novel human leukocyte antigen-DRB1 allele, DRB1*112802, which was identified from a Chinese individual during sequence-based typing. The new allele is identical to DRB1*112801 except for one nucleotide change at nucleotide 189 (A --> G ), codon 34 Q (CAA) --> Q (CAG), no coding change.

Retrosigmoid keyhole approach to the posterior cranial fossa: an anatomical and clinical study

The purpose of this study is to describe the microsurgical anatomic features, as well as the operative technique for the retrosigmoid keyhole (RSK) approach to the posterior cranial fossa. In the anatomical study, 6 cadaveric heads were dissected to simulate the RSK approach. In the clinical study, the records for 15 patients treated using the RSK approach were examined. We found both conventional and RSK procedures expose the regions superior to the anterolateral margin of the tentorium, inferior to the foramen magnum, and medial to the anterolateral pons and medulla. Clinically, total removal was achieved in 13 out of 15 patients. We feel it is a safe, succinct, and minimally invasive alternative to the traditional retrosigmoid approach in selected patients.

Full length sequence of the HLA-Cw*0361 allele identified in a Chinese Han potential bone marrow donor from Northern China

HLA-Cw*0361 allele differs from Cw*030301 by one nucleotide substitution at nt 566 from T to A, resulting in an amino acid change at codon 165 from Val to Glu.

Identification of a novel HLA-Cw*08 variant allele, Cw*0824

A novel HLA-C allele, Cw*0824, which was identified from an individual of the Han Chinese, differs from Cw*080101 at codon 222 (GAG > AAG ) in exon 4, which results in an amino acid change Glu222Lys.

Elevated ability to compete for limited food resources by 'all-fish' growth hormone transgenic common carp Cyprinus carpio

Food consumption, number of movements and feeding hierarchy of juvenile transgenic common carp Cyprinus carpio and their size-matched non-transgenic conspecifics were measured under conditions of limited food supply. Transgenic fish exhibited 73.3% more movements as well as a higher feeding order, and consumed 1.86 times as many food pellets as their non-transgenic counterparts. After the 10 day experiment, transgenic C. carpio had still not realized their higher growth potential, which may be partly explained by the higher frequency of movements of transgenics and the 'sneaky' feeding strategy used by the non-transgenics. The results indicate that these transgenic fish possess an elevated ability to compete for limited food resources, which could be advantageous after an escape into the wild. It may be that other factors in the natural environment (i.e. predation risk and food distribution), however, would offset this advantage. Thus, these results need to be assessed with caution.

Complete genomic sequence of a novel HLA-B*1325 allele observed in a Chinese Han individual

The complete genomic sequence of HLA-B*1325 allele shows one nucleotide difference from B*130101 at nt 302 where A --> G resulting in an amino acid substitution from Asn(AAC) to Ser(AGC) at codon 77 in exon 2.

Genomic sequence of HLA-Cw*1222 allele identified in a Chinese Han patient from Southern China

The genomic sequence of HLA-Cw*1222 allele is identical to Cw*120202 except for a single-nucleotide substitution at codon 87 (CAG-->CGG) resulting in an amino acid change from Gln to Arg.

Elevated levels of serum antibodies against Saccharomyces cerevisiae mannan in patients with systemic lupus erythematosus

This study was undertaken to investigate whether levels of anti- Saccharomyces cerevisiae mannan antibodies (ASCMAs), a serological marker for Crohn’s disease, seronegative spondyloarthritis and Behcet’s disease, also correlate with systemic lupus erythematosus (SLE) in humans. Serum samples from healthy volunteers ( n = 152) and patients with SLE ( n = 40) were compared for ASCMA-IgA, -IgG and -IgM levels using enzyme linked immunosorbent assays. ASCMA-IgG, but not IgM and IgA, prevalence was significantly raised in active SLE patients (57.5%) compared with healthy controls (8.5%). ASCMA-IgG levels in SLE patients during remission were relatively lower, indicating a possible correlation with disease activity. These results differ from a previous study, which did not detect a difference between ASCMA levels in SLE patients and healthy control. It remains to be evaluated whether elevated ASCMA-levels are common to all rheumatic disorders.