Differentiation between Supratentorial Single Brain Metastases and High Grade Astrocytic Tumors: an Evaluation of Different DSC MRI Measurements

This study evaluated the role of different perfusion MRI measurements in the pre-operative differentiation between single brain metastases and high grade astrocytic tumors. 24 high-grade astrocytic tumors and 29 single metastases were studied. A gradient echo-planar sequence was used for DSC MRI. Relative cerebral blood volume, cerebral blood flow and mean transit time in both tumor parenchyma (T rCBV, T rCBF and T rMTT) and peritumoral edema (P rCBV, P rCBF and P rMTT) were measured. Mann-Whitney tests were used to assess differences between single brain metastases and high grade astrocytic tumors. Receiver operating characteristic analyses were performed to determine optimum thresholds for tumor differentiation. Sensitivity, specificity and accuracy for identifying brain metastases were calculated. Mean T rCBV, T rCBF, P rCBV and P CBF of brain metastases (2.75±1.72, 2.51±2.09, 1.05±0.53, 0.87±0.40) differed statistically (P <0.05) from those of high grade astrocytic tumors (6.00±2.17, 5.68±2.35, 1.77±1.19 and 1.58±0.99). No statistical difference was found between mean rMTTs of these two entities (P >0.05). Based on the area under the ROC curves (AUC), the efficiency of T rCBV and T rCBF for correct diagnosis of brain metastases is almost identical (AUC: 0.899, 0.890 respectively) and superior to other measurements. A threshold value of 3.50 for T rCBF provided the same specificity (86.7) as that of T rCBV but higher sensitivity (86.2) and accuracy (86.3). Different perfusion measurements can be used to differentiate single metastases from high-grade astrocytic tumors. T rCBF showed the highest diagnostic efficiency among these measurements.

Discordance in HIV-1 viral loads and antiretroviral drug concentrations comparing semen and blood plasma

OBJECTIVES

For individuals not on antiretroviral therapy, the risk of heterosexual transmission of HIV appears negligible when blood plasma (BP) viral loads are <1500 HIV-1 RNA copies/mL. It is not clear whether this observation can be extrapolated to individuals on highly active antiretroviral therapy (HAART). Because of differential tissue penetration, antiretroviral drug concentrations may be sufficient to maintain an undetectable viral load in the BP yet not achieve adequate levels to suppress HIV in the genital tract. Therefore, we wanted to correlate HIV viral loads and drug concentrations in semen plasma (SP) and BP.

METHODS

Thirty-three men were included. All were on combination antiretroviral therapy with an undetectable BP viral load for at least 1 year. Blood and semen samples were collected within 2 h of each other and tested for HIV RNA by the NucliSens QT (bioMerieux, St Laurent, QC, Canada) method; drug concentrations were determined by liquid chromatography tandem mass spectrometry.

RESULTS

Two of the 33 patients (6.1%) with BP viral loads below detection had time-matched HIV viral loads in SP > or =700 copies/mL. Both patients were on efavirenz, the SP concentrations of which were < or =10% of the levels in BP and well below the minimal therapeutic drug monitoring target concentration required to suppress HIV.

CONCLUSIONS

Because, at least in part, of poor drug penetration into the genital tract, an undetectable HIV viral load in the BP does not guarantee an undetectable viral load in semen. In view of this, caution should be taken in concluding that patients on HAART with suppressed viraemia are sexually non-infectious.

Investigations into the role of ST2 in acute asthma in children

The ST2 gene is a member of the interleukin-1 receptor family and is located on chromosome 2q12, an area of the genome that has been associated with asthma. The soluble product of the ST2 gene, serum ST2 (sST2), has previously been shown to be elevated in adult asthmatic patients. This study investigated the potential role of ST2 in children with acute asthma. Children aged 2-16 years (n = 186) were recruited on presentation with acute asthma in the emergency department. Blood was obtained on presentation and during convalescence. Variables assessed included sST2 levels, a comprehensive assembly of clinical parameters and two polymorphisms in the ST2 gene, -26999G/A, located in the distal promoter region, and ala78glu polymorphism, on exon 3. The A allele of the -26999G/A polymorphism occurred more frequently in asthmatics compared with an unselected control group (P = 0.031). Serum ST2 levels were substantially higher during acute asthma compared with levels after the attack: 0.29 ng/ml (95% confidence interval: 0.23-0.36) and 0.14 ng/ml (0.12-0.17), respectively (P = 0.001) and were inversely related to eosinophil counts during an acute asthma attack (P = 0.002). The -26999AA genotype, as well as the AC haplotype, was associated with asthma severity scores (P = 0.05 and 0.02) compared with the -26999GA and GG genotypes. Serum ST2 levels were not associated with any of the studied genotypes or haplotypes. The observed associations of ST2 genotypes and haplotypes with acute asthma and asthma severity scores as well as the phenotypic differences associated with ST2 polymorphisms suggest that ST2 may play a role in the pathophysiology of asthma.

Phase I dose-escalation study of thoracic radiotherapy in combination with gefitinib in patients with IIIB/IV non-small cell lung cancer (NCT00497250)

e14581

Background: Cinical studies have confirmed that gefitinib, an EGFR-TKI, is effective for some advanced NSCLC patients. Patients with Asian ethnicity are reported to have a higher response rate with gefitinib monotherapy. However, a higher incidence of interstitial lung disease, sometimes lethal, is also found. The combination of gefitinib and radiotherapy has been observed to have a synergistic, anti-proliferative effect against NSCLC in vitro. This phase I study assessed the safety, clinical feasibility and optimally tolerated regimen (OTR) of this combination in patients with pretreated locally advanced or metastatic (IIIB/IV) NSCLC. Methods: Patients with stage IIIB or selected stage IV, failure of platinum-based chemotherapy regimen NSCLC were eligible. Four Cohorts of eight patients each were planned to be treated with escalating doses from 54 to 60 Gy of conformal or intensity- modulated radiotherapy (2Gy/Fx) administered in combination with gefitinib 250mg daily during RT and 60 days after the completion of RT to determine the OTR. Results: Since June 2007, 2 cohorts, a total of 16 patients, were enrolled and treated: 8 stage IIIB and 8 stage IV; 2 squamous-cell carcinoma and 14 adenocarcinoma; 8 smokers and 8 nonsmokers. Prior-chemotherapy regimen was consisted of NP, GP and TP for a median of 3.5 cycles (range, 1–5). Median follow-up time was seven months. Mean progression-free survival time was 5.2 months (median, 3.9; range, 1.7–12.3). Overall, adverse events were mild to moderate in severity. The most frequent grade 2 events included pneumonitis (31%) and dysphagia (19%). There were one treatment-related grade 3 event, which was nausea, and no grade 4 events. Most of the failure patterns were out-of-field (11/13) and the most common distant metastasis organ was the lungs. Three patients are progression-free to date. Conclusions: Thoracic radiotherapy up to 56 Gy concurrent with gefitinib 250 mg daily was well tolerated and clinically active in this group of pretreated Chinese NSCLC patients, including nonsmokers with adenocarcinoma. Accrual is continuing. Sponsorship: This work was partly supported by Program for New Century Excellent Talents in University (NCET), Ministry of Education.

No significant financial relationships to disclose.

Anti-bacterial IgE in the antibody responses of house dust mite allergic children convalescent from asthma exacerbation

Background Atopic sensitization to the house dust mite (HDM) is associated with altered antibody responses to the nasopharyngeal colonizing bacterium Haemophilus influenzae and children admitted to the emergency department for asthma exacerbation have reduced IgG responses to HDM allergens.

Objective To investigate anti‐bacterial and anti‐allergen antibody responses during convalescence from asthma exacerbation and differences found in exacerbations associated with and without viral infection.

Results IgE antibodies to the P6 bacterial antigen increased in 60% of sera during convalescence and for many children achieved titres as high as IgE titres to allergens. In contrast IgE anti‐HDM titres declined during convalescence. The anti‐bacterial IgE titres were the same in subjects with and without virus infection while the anti‐HDM IgE declined more rapidly in virus‐infected subjects. IgG titres to the major HDM allergens showed no consistent increase and the overall IgG anti‐HDM titres even declined in subjects without a virus infection. Anti‐bacterial IgG antibodies in contrast to IgE did not change. Patients with frequent episodic or persistent asthma had similar IgE anti‐bacterial titres to patients with infrequent asthma during the acute phase, although they had reduced IgG titres to both the bacteria and the HDM.

Conclusions During the period following an acute exacerbation of asthma there was a marked and specific increase in anti‐bacterial IgE compared with a reduced IgE response to HDM. This provides further support for the concept of T‐helper type 2 responses to bacterial antigens playing a role in asthma pathogenesis.

Ventricular dilation and elevated aqueductal pulsations in a new experimental model of communicating hydrocephalus

In communicating hydrocephalus (CH), explanations for the symptoms and clear-cut effective treatments remain elusive. Pulsatile flow through the cerebral aqueduct is often significantly elevated, but a clear link between abnormal pulsations and ventriculomegaly has yet to be identified. We sought to demonstrate measurement of pulsatile aqueductal flow of CSF in the rat, and to characterize the temporal changes in CSF pulsations in a new model of CH. Hydrocephalus was induced by injection of kaolin into the basal cisterns of adult rats (n = 18). Ventricular volume and aqueductal pulsations were measured on a 9.4 T MRI over a one month period. Half of the animals developed ventricular dilation, with increased ventricular volume and pulsations as early as one day post-induction, and marked chronic elevations compared to intact controls (volume: 130.15 +/- 83.21 microl vs. 15.52 +/- 2.00 microl; pulsations: 114.51 nl +/- 106.29 vs. 0.72 +/- 0.13 nl). Similar to the clinical presentation, the relationship between ventricular size and pulsations was quite variable. However, the pulsation time-course revealed two distinct sub-types of hydrocephalic animals: those with markedly elevated pulsations which persisted over time, and those with mildly elevated pulsations which returned to near normal levels after one week. These groups were associated with severe and mild ventriculomegaly respectively. Thus, aqueductal flow can be measured in the rat using high-field MRI and basal cistern-induced CH is associated with an immediate change in CSF pulsatility. At the same time, our results highlight the complex nature of aqueductal pulsation and its relationship to ventricular dilation.

Substance P release and neurokinin 1 receptor activation in the rat spinal cord increase with the firing frequency of C-fibers

Both the firing frequency of primary afferents and neurokinin 1 receptor (NK1R) internalization in dorsal horn neurons increase with the intensity of noxious stimulus. Accordingly, we studied how the pattern of firing of primary afferent influences NK1R internalization. In rat spinal cord slices, electrical stimulation of the dorsal root evoked NK1R internalization in lamina I neurons by inducing substance P release from primary afferents. The stimulation frequency had pronounced effects on NK1R internalization, which increased up to 100 Hz and then diminished abruptly at 200 Hz. Peptidase inhibitors increased NK1R internalization at frequencies below 30 Hz, indicating that peptidases limit the access of substance P to the receptor at moderate firing rates. NK1R internalization increased with number of pulses at all frequencies, but maximal internalization was substantially lower at 1-10 Hz than at 30 Hz. Pulses organized into bursts produced the same NK1R internalization as sustained 30 Hz stimulation. To determine whether substance P release induced at high stimulation frequencies was from C-fibers, we recorded compound action potentials in the sciatic nerve of anesthetized rats. We observed substantial NK1R internalization when stimulating at intensities evoking a C-elevation, but not at intensities evoking only an Adelta-elevation. Each pulse in trains at frequencies up to 100 Hz evoked a C-elevation, demonstrating that C-fibers can follow these high frequencies. C-elevation amplitudes declined progressively with increasing stimulation frequency, which was likely caused by a combination of factors including temporal dispersion. In conclusion, the instantaneous firing frequency in C-fibers determines the amount of substance P released by noxious stimuli.

Neovascularization in an arterio-venous loop-containing tissue engineering chamber: role of NADPH oxidase

Using an in vivo arterio-venous loop-containing tissue-engineering chamber, we have created a variety of vascularized tissue blocks, including functional myocardium. The viability of the transplanted cells is limited by the rate of neovascularization in the chamber. A Nox2-containing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is thought to have a critical role in ischaemic angiogenesis. In this study we investigated whether NADPH oxidase is involved in the neovascularization process in the tissue-engineering chamber. New blood vessels originating from the venous and the arterial ends of the loop could be identified after 3 days, and the vessel density (by lectin staining) peaked after 7 days and was maintained for at least 14 days. This was accompanied by granulation tissue formation and concomitant increase in the mRNA level of Nox4 NADPH oxidase. Although the total level of Nox2 mRNA in the chamber tissue decreased from day 3 to day 7, immunohistochemistry identified a strong expression of Nox2 in the endothelial cells of the new vessels. In human microvascular endothelial cells, the NADPH oxidase inhibitor apocynin reduced NADPH oxidase activity and inhibited the angiogenic responses in vitro. Local treatment with the NADPH oxidase inhibitors apocynin or gp91ds-tat peptide significantly suppressed the vessel growth in the chamber. In conclusion, NADPH oxidase-dependent redox signalling is important for neovascularization in this novel tissue-engineering chamber in vivo, and boosting this signalling might be a new approach to extending vascularization and tissue growth.

Recombinant Human Erythropoietin Protects against Experimental Spinal Cord Trauma Injury by Regulating Expression of the Proteins MKP-1 and p-ERK

The present study explored the tissue-protective effect of erythropoietin in rats after experimental spinal cord injury (SCI) produced by dropping a weight onto surgically exposed spinal cord. Sixty rats were randomized to sham operation (spinal cord exposure; control), SCI plus intraperitoneal saline injection, or SCI plus intraperitoneal erythropoietin injection. Locomotor function was evaluated with Basso, Beattie and Bresnahan scores 1 day (24 h) and 7 days later, and rats were then killed for analysis of lesion site tissue. Compared with saline-treated SCI rats, erythropoietin-treated SCI rats showed significantly less locomotor dysfunction and faster locomotor recovery. Immunohistochemistry showed that erythropoietin-treated SCI rats had a significantly lower phospho-extracellular signal-regulated kinase (p-ERK) protein expression and a significantly higher mitogen-activated protein kinase phosphatase-1 (MKP-1) protein expression than saline-treated SCI rats. Haematoxylin–eosin staining showed progressive disruption of dorsal white matter and neuron loss after SCI; lesions were less severe and there was more neuron regeneration in the erythropoietin group than in the saline group. It is concluded that erythropoietin reduces pathological changes and SCI severity via down-regulation of p-ERK and up-regulation of MKP-1.

Imaging the effects of propofol on human cerebral glucose metabolism using positron emission tomography

The effects of propofol on glucose metabolism in different cerebral regions were observed, using positron emission tomography (PET) technology, to determine a possible cerebral target region. Seven healthy volunteers were injected with (18)F-fluorodeoxyglucose developing agent for PET scanning whilst awake (control group T1), during sedation (induced by 1.5 microg/ml propofol administered by target controlled injection [TCI], group T2) and when unconsciousness (induced by 2.5 microg/ml propofol administered by TCI, group T3). Whole brain glucose metabolism was reduced during propofol anaesthesia; this was initially observed in the cortical areas at the lower dose of propofol (group T2) but extended to the subcortical regions, especially the thalamus and hippocampus, at the higher dose (group T3). This suggests that these regions of the brain might be important targets that are susceptible to propofol.

Monte Carlo electron-trajectory simulations in bright-field and dark-field STEM: implications for tomography of thick biological sections

A Monte Carlo electron-trajectory calculation has been implemented to assess the optimal detector configuration for scanning transmission electron microscopy (STEM) tomography of thick biological sections. By modeling specimens containing 2 and 3 at% osmium in a carbon matrix, it was found that for 1-microm-thick samples the bright-field (BF) and annular dark-field (ADF) signals give similar contrast and signal-to-noise ratio provided the ADF inner angle and BF outer angle are chosen optimally. Spatial resolution in STEM imaging of thick sections is compromised by multiple elastic scattering which results in a spread of scattering angles and thus a spread in lateral distances of the electrons leaving the bottom surface. However, the simulations reveal that a large fraction of these multiply scattered electrons are excluded from the BF detector, which results in higher spatial resolution in BF than in high-angle ADF images for objects situated towards the bottom of the sample. The calculations imply that STEM electron tomography of thick sections should be performed using a BF rather than an ADF detector. This advantage was verified by recording simultaneous BF and high-angle ADF STEM tomographic tilt series from a stained 600-nm-thick section of C. elegans. It was found that loss of spatial resolution occurred markedly at the bottom surface of the specimen in the ADF STEM but significantly less in the BF STEM tomographic reconstruction. Our results indicate that it might be feasible to use BF STEM tomography to determine the 3D structure of whole eukaryotic microorganisms prepared by freeze-substitution, embedding, and sectioning.

HoxC6 regulation of early mammary epithelial growth and differentiation: implications for breast cancer potential

Abstract #2010

Background: Early menarche and breast development are increasingly common risk factors for breast cancer. Epigenetic mechanisms implicated include natural and anthropogenic steroids, such as estrogens, that disrupt endocrine signaling and dysregulate stem cell homeostasis. Animal models show that, although a proliferative response to estrogens in mammary epithelium is not observed until near puberty, in utero or neonatal exposure can recapitulate aberrant breast development. The molecular basis for the delay in proliferative response remains poorly understood and assessments of agent activity, potency and risk remain inaccurate. Here, we provide a candidate molecular mechanism involving the homeobox transcription factor HoxC6, through which more accurate assessments may be facilitated.&#x2028; Materials & Methods: Genetically and hormonally manipulated in vivo mouse models (HoxC6 targeted disruption, C6KO; and mammary epithelial-specific inducible HoxC6, MMTV-rtTA TRE-HoxC6-IRES-EGFP) and in vitro human breast cancer cell lines (MCF10A, MCF7 and MDA-MB-231; "231") were used to assess impacts on mammary epithelial growth, differentiation and expression of HoxC6 and its direct target genes IGFBP3, CD44 and FGFR2. Cell lines were manipulated using HoxC6 shRNA and cDNA lentivirus and activated Akt isoform retroviral expression vectors. Gene expression and signaling were measured by quantitative RT-qPCR, IHC, Western blot and using the BioPlex200 Multiplex System.&#x2028; Results: RT-qPCR analysis shows HoxC6 expression elevated in well-differentiated cell lines (MCF10A, 5.06X; MCF7, 5.16X) and decreased in more aggressive tumor cell lines (-1.95X, 231 cells; relative to A549 cells). HoxC6 knockdown in MCF10A cells results in an inhibition of cellular growth and decreased branching in 3D cultures and dysregulation of HoxC6 target genes. These results are consistent with in vivo results in which C6KO causes defective postnatal mammary epithelial growth/branching. Rescue of growth defects in knockdown MCF10A cells is achieved to varying extents with myristoylated Akt isoforms, however morphological defects persist and are associated with EMT. HoxC6 induction in stem cells is associated with altered self-renewal and differentiation. HoxC6 repression by estrogens was assessed in vivo under conditions of neonatal estrogen exposure and estrogen-free diets, showing alterations in HoxC6 and target gene expressions and other phenotypic changes.&#x2028; Discussion: Based on our results, we will present a model in which HoxC6 is estrogen-responsive and coordinates mammary stem/progenitor cell homeostatic pathways, including FGF and GH-IGF1 signaling in the control of pool size and branching morphogenesis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2010.

Streptococcus cristatus attenuates Fusobacterium nucleatum-induced interleukin-8 expression in oral epithelial cells

BACKGROUND AND OBJECTIVE

Oral epithelial cells may be invaded by a polymicrobial intracellular flora, including pathogens together with commensals. Various oral pathogens can induce the production of interleukin-8, a potent neutrophil chemotractant, in oral epithelial cells. Evidence from the gut suggests that commensal species may modulate inflammatory responses to pathogens. The aim of this study was to examine the interleukin-8 responses of oral epithelial cells to an oral pro-inflammatory species, Fusobacterium nucleatum, in combination with an oral commensal, Streptococcus cristatus.

MATERIAL AND METHODS

KB, TERT-2, TR146 and SCC15 cells were cocultured with F. nucleatum and S. cristatus, either alone or in combination, at 37 degrees C in 5% CO2 under various conditions. The mRNA expression of interleukin-8 was analyzed by reverse transcription-polymerase chain reaction and protein secretion was measured by enzyme-linked immunosorbent assay.

RESULTS

F. nucleatum alone evoked a potent interleukin-8 response, whereas S. cristatus alone did not induce significant interleukin-8 expression in oral epithelial cells. When present together, S. cristatus attenuated the F. nucleatum-induced interleukin-8 production in the four oral epithelial cell lines to varying degrees. The inhibitory effect of S. cristatus was independent of its viability and its co-aggregation with F. nucleatum, was not related to soluble bacterial products and appeared to require bacterial contact with epithelial cells. Similar effects were seen with several other species of oral streptococci.

CONCLUSION

Our data suggest that S. cristatus may exert immunomodulatory effects on the interleukin-8 response of oral epithelial cells to F. nucleatum challenge.

Brain death affects the hepatic immunogenicity of pigs

OBJECTIVE

The purpose of this study was to observe how the brain-death state affects the hepatic immunogenicity of pigs.

MATERIALS AND METHODS

Twelve healthy ChangBai pigs were allocated randomly to 2 groups: control group (n = 6) with Foley catheter balloon placed intracalvarium for 24 hours only versus brain-death group (n = 6) with brain death for 24 hours. The serum and hepatic tissues were obtained at 6, 12, and 24 hours after the initial confirmation of brain death. Tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 were determined by enzyme-linked immunosorbent assay (ELISA). The major histocompatibility complex class II (MHC-II) was determined by immunohistochemistry, and the intercellular adhesion molecule-1 (ICAM-1) mRNA and monocyte chemotactic protein-1 (MCP-1) mRNA by real-time polymerase chain reaction (PCR).

RESULTS

The serum TNF-alpha and IL-6, MHC-II, ICAM-1 mRNA, and MCP-1 mRNA in hepatic tissues in the brain-death group were higher than in the control group; they all increased with time.

CONCLUSION

Brain death increased liver immunogenicity, which may increase the immune lesion and rejection after transplantation.

Does the relationship between IgE and the CD14 gene depend on ethnicity?

This review considers the data from studies analysing associations between the CD14C-159T single nucleotide polymorphism (SNP) and asthmatic phenotypes and discusses the variability of the conclusions. By searching PubMed and EMBASE for articles on CD14C-159T -related population or family-based association studies, 47 were identified up till September 2007. Collectively, the studies reviewed herein consistently showed population differences in frequencies of the alleles of the SNP, with African descent having the highest C allele frequencies, followed by Caucasians and Asians. The T allele of the SNP was associated with increased sCD14 in some studies but not in others. Inconsistently, the C allele, or even occasionally the T allele, was associated with atopic phenotypes in a population subgroup. There are several explanations for these inconsistencies, including lack of power, linkage disequilibrium, gene-gene interactions, population admixture and gene-environment interactions. If the SNP was associated with functional changes to the coded protein and thus modulating susceptibility to allergic disease, its effect may be modest and dependent on other co-existent, ethnicity-specific, genetic or environmental risk factors.