Grand challenges in mapping the human brain: NSF workshop report

This report summarizes the outcomes of the NSF Workshop on Mapping and Engineering the Brain, held at Arlington, VA, during August 13-14, 2013. Three grand challenges were identified, including high spatiotemporal resolution neuroimaging, perturbation-based neuroimaging, and neuroimaging in naturalistic environments. It was highlighted that each grand challenge requires groundbreaking discoveries, enabling technologies, appropriate knowledge transfer, and multi- and transdisciplinary education and training for success.

Metastatic breast cancer detection and therapy monitoring using folate-targeting flow cytometry

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Background: Circulating tumor cell (CTC) has emerged as a valuable surrogate tumor marker for cancer diagnosis, prognosis, therapy personalization, and drug discovery. To identify CTCs, EpCAM and/or cytokeratin have been commonly used; however, their expression may diminish for subgroups of breast cancers or during epithelial-mesenchymal transition. A unique approach by targeting folate receptor (FR) on CTCs overcomes the limitation. Cancer cells overexpress FR with high affinity (KD=0.1 nM) to internalize high levels of folate for rapid growth. FR is also found upregulated in most cancers, while at very low levels in normal tissues.

Methods: A flow cytometry based in-vitro CTC assay kit (OncoIVDx) was developed by IV Diagnostics Inc to specifically enumerate CTCs which overexpress FRs. 20 mL of 9 metastatic breast cancer (MBC) patients' peripheral blood was collected using CellSave tube before and after the treatment in midst of therapy. CTCs were tagged by fluorescently labeled folate conjugate, while leukocytes were counterstained by anti-CD45. To absolutely count the rare CTCs, a fluorescent bead was added serving internal control.

Results: Table.

Conclusions: No obvious shift in dot plots was found for patients' leucocytes compared to those in normal sample. Tumor size, histologic grade, nodal involvement and lymphovascular invasion (LVI) did not display a significant association with CTC presence, although more positive nodes with identified LVI might indicate an unfavorable increase in CTC counts. CTC presence was found associated with serum marker CA27.29. A score of 30 and less correlated with CTC response to the treatment. Chemotherapy alone or in combination with hormone therapy did not correlate with the change in CTC counts after treatment, except for hormone therapy alone. Unfavorable progression of cancers could be predicated for the patients with approximately 25 and more CTCs. We would like to thank NIH/NCI for SBIR phase I grant (1R43CA13789301A1).

[Table: see text]

Intestinal ciprofloxacin efflux: the role of breast cancer resistance protein (ABCG2)

Intestinal secretory movement of the fluoroquinolone antibiotic, ciprofloxacin, may limit its oral bioavailability. Active ATP-binding cassette (ABC) transporters such as breast cancer resistance protein (BCRP) have been implicated in ciprofloxacin transport. The aim of this study was to test the hypothesis that BCRP alone mediates intestinal ciprofloxacin secretion. The involvement of ABC transport proteins in ciprofloxacin secretory flux was investigated with the combined use of transfected cell lines [bcrp1/BCRP-Madin-Darby canine kidney II (MDCKII) and multidrug resistance-related protein 4 (MRP4)-human embryonic kidney (HEK) 293] and human intestinal Caco-2 cells, combined with pharmacological inhibition using 3-(6-isobutyl-9-methoxy-1,4-dioxo-1,2,3,4,6, 7,12,12a-octahydropyrazino[1',2':1,6]pyrido[3,4-b]indol-3-yl)-propionic acid tert-butyl ester (Ko143), cyclosporine, 3-[[3-[2-(7-chloroquinolin-2-yl)vinyl]phenyl]-(2-dimethylcarbamoylethylsulfanyl)methylsulfanyl] propionic acid (MK571), and verapamil as ABC-selective inhibitors. In addition, the regional variation in secretory capacity was investigated using male Han Wistar rat intestine mounted in Ussing chambers, and the first indicative measurements of ciprofloxacin transport by ex vivo human jejunum were made. Active, Ko143-sensitive ciprofloxacin secretion was observed in bcrp1-MDCKII cell layers, but in low-passage (BCRP-expressing) Caco-2 cell layers only a 54% fraction was Ko143-sensitive. Ciprofloxacin accumulation was lower in MRP4-HEK293 cells than in the parent line, indicating that ciprofloxacin is also a substrate for this transporter. Ciprofloxacin secretion by Caco-2 cell layers was not inhibited by MK571. Secretory flux showed marked regional variability in the rat intestine, increasing from the duodenum to peak in the ileum. Ciprofloxacin secretion was present in human jejunum and was reduced by Ko143 but showed marked interindividual variability. Ciprofloxacin is a substrate for human and rodent BCRP. An additional pathway for ciprofloxacin secretion exists in Caco-2 cells, which is unlikely to be MRP(4)-mediated. BCRP is likely to be the dominant transport mechanism for ciprofloxacin efflux in both rat and human jejunum.

Carcinomatous meningitis: the natural history of successfully treated metastatic bladder cancer

Carcinomatous meningitis due to bladder cancer is a rare entity reported only in case reports. Optimal therapy is thus poorly defined with earlier cases reporting an unsuccessful outcome. Here we report a case of late carcinomatous meningitis secondary to transitional cell carcinoma (TCC) of the bladder occurring in a patient in complete remission. He was successfully treated with intrathecal methotrexate and whole brain irradiation and experienced prolonged survival after treatment. With modern chemotherapy increasing complete remissions and survival rates in patients with TCC, more and more patients are being reported with carcinomatous meningitis. We raise the question of whether central nervous system prophylaxis should be considered in patients with TCC achieving a complete remission to chemotherapy in the metastatic setting.

A stretchable electrode array for non-invasive, skin-mounted measurement of electrocardiography (ECG), electromyography (EMG) and electroencephalography (EEG)

This paper reports a class of stretchable electrode array capable of intimate, conformal integration onto the curvilinear surfaces of skin on the human body. The designs employ conventional metallic conductors but in optimized mechanical layouts, on soft, thin elastomeric substrates. These devices exhibit an ability to record spontaneous EEG activity even without conductive electrolyte gels, with recorded alpha rhythm responses that are 40% stronger than those collected using conventional tin electrodes and gels under otherwise similar conditions. The same type of device can also measure high quality ECG and EMG signals. The results suggest broad utility for skin-mounted measurements of electrical activity in the body, with advantages in signal levels, wearability and modes of integration compared to alternatives.

Regulation of methionine synthesis in Escherichia coli: Effect of metJ gene product and S-adenosylmethionine on the expression of the metF gene

The regulation of the expression of the Escherichia coli metF gene, which codes for 5,10-methylenetet-rahydrofolate reductase (EC 1.1.99.15), has been investigated by using a simplified DNA-directed in vitro system that measures the formation of the first dipeptide (fMet-Ser) of the gene product. The synthesis of fMet-Ser directed by a plasmid containing the metF gene is specifically inhibited by metJ protein (repressor protein). S-Adenosylmethionine enhances the inhibition by the metJ protein of metF gene expression. The inhibition by the metJ protein is at the level of transcription and the results suggest that S-adenosylmethionine is functioning as an allosteric effector.

Environmental tobacco smoke and fetal health: systematic review and meta-analysis

OBJECTIVE

To determine the effects of environmental tobacco smoke (ETS) exposure on birth outcomes.

DESIGN

A systematic review and meta-analysis was performed in accordance with MOOSE guidelines. MEDLINE, EMBASE, CINAHL and LILACS (up to October 2007), were searched and also reviews and reference lists from publications, with no language restrictions. Pooled mean differences and odds ratios (ORs) with 95% confidence intervals were estimated using data extracted from papers, based on random effect models.

SETTING

Comparative epidemiological studies.

PATIENTS

Pregnant women or women who have given birth.

EXPOSURES

Maternal exposure to ETS during pregnancy.

MAIN OUTCOME MEASURES

Mean birth weight and proportion of premature infants.

RESULTS

58 studies were included; 53 used cohort designs, 23 ascertaining ETS exposure prospectively and 30 retrospectively; 5 used case-control designs. In prospective studies, ETS exposure was associated with a 33 g (95% CI 16 to 51) reduction in mean birth weight, and in retrospective studies a 40 g (95% CI 26 to 54) reduction. ETS exposure was also associated with an increased risk of low birth weight (birth weight <2500 g; prospective studies: OR 1.32, 95% CI 1.07 to 1.63; retrospective studies: OR 1.22, 95% CI 1.08 to 1.37). The risk of small for gestational age (<10th centile) birth was significantly associated with ETS exposure only in retrospective studies (OR 1.21, 95% CI 1.06 to 1.37). There was no effect of ETS exposure on gestational age.

CONCLUSIONS

Exposure of non-smoking pregnant women to ETS reduces mean birth weight by 33 g or more, and increases the risk of birth weight below 2500 g by 22%, but has no clear effect on gestation or the risk of being small for gestational age.

Induction of P-glycoprotein expression and function in human intestinal epithelial cells (T84)

Intestinal induction of Pgp is known to limit the oral availability of certain drug compounds and give rise to detrimental drug-drug interactions. We have investigated the induction of P-glycoprotein (Pgp; MDR1) activity in a human intestinal epithelial cell line (T84) following pre-exposure to a panel of drug compounds, reported to be Pgp substrates, inhibitors or inducers. Human MDR1-transfected MDCKII epithelial monolayers were used to assess Pgp substrate interactions and inhibition of digoxin secretion by the selected drug compounds. The T84 cell line was used to assess induction of Pgp-mediated digoxin secretion following pre-exposure to the same compounds. Changes in gene expression (MDR1, MRP2, PXR and CAR) were determined by quantitative RT-PCR. Net transepithelial digoxin secretion was increased (1.3 fold, n=6, P<0.05) following pre-exposure to the PXR activator hyperforin (100nM, 72h), as was MDR1 mRNA expression (3.0 fold, n=4, P<0.05). A number of Pgp substrates (quinidine, amprenavir, irinotecan, topotecan, atorvastatin and erythromycin) induced net digoxin secretion, as did the non-Pgp substrate artemisinin. Various non-Pgp substrates demonstrated inhibition of digoxin secretion (verapamil, mifepristone, clotrimazole, mevastatin, diltiazem and isradipine) but did not induce Pgp-mediated digoxin secretion. Of the compounds that increased Pgp secretion, quinidine, topotecan, atorvastatin and amprenavir pre-exposure also elevated MDR1 mRNA levels, whereas erythromycin, irinotecan and artemisinin displayed no change in transcript levels. This indicates possible post-translational regulation of digoxin secretion. Finally, a strong correlation between drug modulation of MRP2 and PXR mRNA expression levels was evident.

Rifampin and digoxin induction of MDR1 expression and function in human intestinal (T84) epithelial cells

BACKGROUND AND PURPOSE

Oral drug bioavailability is limited by intestinal expression of P-glycoprotein (MDR1, Pgp, ABCB1) whose capacity is regulated via nuclear receptors e.g. the pregnane X receptor (PXR, SXR, NR1I2). In order to study dynamic regulation of MDR1 transport capacity we have identified the T84 epithelial cell-line as a model for human intestine co-expressing MDR1 with PXR. The ability of rifampin, a known PXR agonist and digoxin, a model MDR1 substrate, to regulate MDR1 expression and transport activity has been tested, in these T84 cells.

EXPERIMENTAL APPROACH

Transport was assayed by bi-directional [(3)H]-digoxin transepithelial fluxes across epithelial layers of T84 cells seeded onto permeable filter supports following pre-exposure to rifampin and digoxin. Quantitative real-time PCR, Western blotting and immunocytochemistry were used to correlate induction of MDR1 transcript and protein levels with transport activity.

KEY RESULTS

Rifampin exposure (10 microM, 72 hours) increased MDR1 transcript levels (3.4 fold), MDR1 total protein levels (4.4 fold), apical MDR1 protein (2.7 fold) and functional activity of MDR1 (1.2 fold). Pre-incubation with digoxin (1 microM, 72 hours) potently induced MDR1 transcript levels (92 fold), total protein (7 fold), apical MDR1 protein (4.7 fold) and functional activity (1.75 fold). Whereas PXR expression was increased by rifampin incubation (2 fold), digoxin reduced PXR expression (0.3 fold).

CONCLUSIONS AND IMPLICATIONS

Chronic digoxin pre-treatment markedly upregulates MDR1 expression and secretory capacity of T84 epithelia. Digoxin-induced changes in MDR1 levels are distinct from PXR-mediated changes resulting from rifampin exposure.

Drugs to support smoking cessation in UK general practice: are evidence based guidelines being followed?

BACKGROUND

Prescribing drugs to support smoking cessation is one of the most cost effective interventions in primary care, but there is evidence they are underused. Little is known about how far guidelines have been adopted.

AIMS

To examine the context in which nicotine replacement therapy (NRT) and bupropion are prescribed in UK general practice and whether guidelines are being followed.

DESIGN

Patient questionnaire survey.

SETTING

Twenty five general practices from the Trent Focus Collaborative Research Network in South Yorkshire and East Midlands, UK.

METHODS

Participating practices posted a questionnaire to up to 40 patients prescribed NRT and bupropion respectively in the previous 3-9 months.

RESULTS

The response rate for people prescribed NRT was 44.7% (323/723) and for bupropion 42.5% (77/181). Patients reported initiating the prescription request in 258 cases (65%), whereas GPs were reported as suggesting it in 49 (12%), smoking cessation services (SCS) in 38 (10%), and practice nurses in 36 (9%). Of those who could recall the content of the consultation in which NRT or bupropion was prescribed, 191 (79%) reported receiving advice on treatment use and 209 (68%) were encouraged to set a quit date. Follow up by SCS was recommended to 186 (64%) and practice follow up was offered to 212 (63%), but 41 (15%) reported no offer of follow up support.

CONCLUSIONS

The majority of patients reported receiving advice and follow up in line with guidelines. However, relatively few prescriptions were suggested by GPs or practice nurses and, in a significant minority of cases, neither follow up by the practice nor additional support from SCS was recommended. More active implementation of guidelines could increase the impact of general practice on the prevalence of smoking.

Smoking cessation treatment in primary care: prospective cohort study

OBJECTIVE

To compare the characteristics of smokers who do and do not receive smoking cessation treatment in primary care.

DESIGN

Prospective cohort study using practices registered with the pilot QRESEARCH database.

SETTING

156,550 patients aged 18 years and over from 39 general practices located within four strategic health authorities, representing the former Trent Region, UK.

SUBJECTS

Patients registered with practices between 1 April 2001 and 31 March 2003 aged 18 years and over who were identified as smokers before the two year study period.

OUTCOME

Prescription for smoking cessation treatment (nicotine replacement therapy (NRT) or bupropion) in the two year study period.

VARIABLES

Age, sex, deprivation score, co-morbidity.

RESULTS

Of the 29,492 patients recorded as current smokers at the start of the study period 1892 (6.4%) were given prescriptions for smoking cessation treatment during the subsequent two years. Of these, 1378 (72.8%) were given NRT alone, 406 (21.5%) bupropion alone, and 108 (5.7%) both treatments. Smokers were more likely to receive smoking cessation treatment if they lived in the most deprived areas (odds ratio (OR) for the most relative to the least deprived fifth, adjusted for sex, age, and co-morbidity, 1.50, 95% confidence interval (CI) 1.26 to 1.78), and if they were aged 25-74 years compared to 18-24 years or 75 and over. Smokers with co-morbidity were also more likely to receive smoking cessation treatment. Smokers were less likely to receive smoking cessation treatment if they were male (adjusted OR 0.68, 95% CI 0.62 to 0.75).

CONCLUSION

The low proportion of smokers being prescribed these products strongly suggests that a major public health opportunity to prevent smoking related illness is being missed.