Development of new photon-counting detectors for single-molecule fluorescence microscopy

Two optical configurations are commonly used in single-molecule fluorescence microscopy: point-like excitation and detection to study freely diffusing molecules, and wide field illumination and detection to study surface immobilized or slowly diffusing molecules. Both approaches have common features, but also differ in significant aspects. In particular, they use different detectors, which share some requirements but also have major technical differences. Currently, two types of detectors best fulfil the needs of each approach: single-photon-counting avalanche diodes (SPADs) for point-like detection, and electron-multiplying charge-coupled devices (EMCCDs) for wide field detection. However, there is room for improvements in both cases. The first configuration suffers from low throughput owing to the analysis of data from a single location. The second, on the other hand, is limited to relatively low frame rates and loses the benefit of single-photon-counting approaches. During the past few years, new developments in point-like and wide field detectors have started addressing some of these issues. Here, we describe our recent progresses towards increasing the throughput of single-molecule fluorescence spectroscopy in solution using parallel arrays of SPADs. We also discuss our development of large area photon-counting cameras achieving subnanosecond resolution for fluorescence lifetime imaging applications at the single-molecule level.

Past, present, and future of endovascular stroke therapies

Endovascular therapy in the acute management of ischemic stroke has become more common with technologic advances, such as easier navigation into the intracranial circulation and improved treatment efficacy with the advent of revascularization devices. This select review outlines milestones in the application of endovascular therapy in acute ischemic stroke (AIS) and offers some insight into important factors influencing the future directions of endovascular AIS treatment. In particular, we discuss the evolution of endovascular devices for AIS and how ingenuity continues to offer novel treatments. With these advances, the future of endovascular AIS treatment is promising.

Ages at different reproductive events, numbers of menstrual cycles in between and breast cancer risk

One hundred and seventy-five pathologically confirmed new cases of female breast cancer in National Taiwan University Hospital were selected as the case group. Four hundred and fifty-seven inpatient controls were individually matched for each case by age and date of admission. Information of reproductive factors and potential confounders were collected from questionnaire interview and medical records. Menstrual cycles before and after first fuIl-term pregnancy were estimated from the questionnaire. Conditional logistic regression was used to estimate the effects of reproductive risk factors and numbers of menstrual cycles before and after first full-term pregnancy. After adjusting for educational level, body mass index, family history of breast cancer and oral contraceptive use, age at menarche and menopause only showed borderline significance. Age at first full-term birth predicted breast cancer risk better. Parity was the most important protective factor. Number of menstrual cycles before first full-term pregnancy was also positively associated with breast cancer risk with linear trends.

Accuracy of noninvasive quantification of brain NAA concentrations using PRESS sequence: verification in a swine model with external standard

The metabolite ratios had been employed in the field of MR spectroscopy (MRS) for a long period. The main drawback of metabolite ratio is that ratio results are not comparable with absolute metabolite concentration in vivo. The purpose of this study was to examine the accuracy of noninvasive quantification of brain N-acetylaspartate (NAA) concentrations using previously reported MR external standard method. Eight swine were scanned on a GE 1.5 T scanner with a standard head coil. The external standard method was utilized with a sphere filled with NAA, GABA, glutamine, glutamate, creatine, choline chloride, and myo-inositol. The position resolved spectroscopy (PRESS) sequence was used with TE=135 msec, TR=1500 msec, and 128 scan averages. The analysis of MRS was done with SAGE/IDL program. In vivo NAA concentration was obtained using the equation S=N * e(-TE/T₂) * [1-e(-TR/T₁). In vitro NAA concentration was measured by high performance liquid chromatography (HPLC). In the MRS group, the mean concentration of NAA was 10.03 plusmn 0.74 mmol/kg. In the HPLC group, the mean concentration of NAA was 9.22 plusmn 0.55 mmol/kg. There was no significant difference between the two groups (p = 0.46). However, slightly higher value was observed in the MRS group (7/8 swine), compared with HPLC group. The range of differences was between 0.02~2.05 mmol/kg. MRS external reference method could be more accurate than internal reference method. ¹H MRS does not distinguish between N-acetyl resonance frequencies and other N-acetylated amino acids.

Tuning the performance of organic spintronic devices using x-ray generated traps

X rays produced during electron-beam deposition of metallic electrodes drastically change the performance of organic spintronic devices. The x rays generate traps with an activation energy of ≈0.5  eV in a commonly used organic. These traps lead to a dramatic decrease in spin-diffusion length in organic spin valves. In organic magnetoresistive (OMAR) devices, however, the traps strongly enhance magnetoresistance. OMAR is an intrinsic magnetotransport phenomenon and does not rely on spin injection. We discuss our observations in the framework of currently existing theories.

Involvement of fatty acid metabolism in the hepatotoxicity induced by divalproex sodium

Divalproex sodium is an antiepileptic drug. Hepatotoxicity is one of the most common side effects induced by divalproex sodium. Impaired fatty acid metabolism is considered to play an important role in the drug-induced hepatotoxicity. The sterol regulatory element-binding protein 1c (SREBP-1c) and peroxisome proliferator-activated receptor α (PPARα) are two key transcription factors involved, respectively, in fatty acid synthesis and degradation in liver. In the present study, we investigated the hepatotoxicity induced by divalproex sodium and its potential mechanism. The results indicated that divalproex sodium significantly decreased the cell viability and increased lactate dehydrogenase leakage in hepatocytes. The activities of alanine aminotransferase and aspartate transaminase were increased in hepatocytes treated with divalproex sodium. Furthermore, divalproex sodium activated SREBP-1c and increased the mRNA expressions of acetyl-CoA carboxylase 1, fatty acid synthase and stearoyl-CoA desaturase 1. Divalproex sodium also inhibited PPARα and decreased the messenger RNA expressions of 3-hydroxy-3-methylglutaryl-CoA synthase 2 and carnitine palmitoyltransferase 1A. These results suggest that the hepatotoxicity induced by divalproex sodium may be related with fatty acid synthesis and degradation mediated by SREBP-1c and PPARα in hepatocytes.

Are existing measures of overall diet quality associated with peak bone mass in young premenopausal women?

BACKGROUND

  Low peak bone mass in young adulthood is associated with an increased risk of osteoporosis and fracture after menopause, and an understanding of the modifiable factors that contribute to low peak bone mass is important for fracture prevention. Diet is an important modifiable factor linked to bone health and, although studies have examined the role of individual dietary components in bone health, bone growth and maintenance are complex processes, and such studies may not adequately represent the role of diet in these processes.

METHODS

  To address this issue, a cross-sectional analysis of 226 healthy, premenopausal women aged 18-30 years was conducted to determine whether existing indices of overall diet quality are associated with bone density in premenopausal women nearing peak bone mass. Bone density was measured using dual-energy X-ray absorptiometry and diet quality was measured using two overall diet scores based on current dietary guidelines: the Recommended Food Score and the Alternate Healthy Eating Index (AHEI).

RESULTS

  In the multiple linear regression, bone density did not increase across quartiles of either diet quality score and was not associated with continuous diet quality variables. Furthermore, none of the individual AHEI components (e.g. fruit intake, vegetable intake) were associated with bone density.

CONCLUSIONS

  These findings suggest that existing diet quality scores are not appropriate for studies of peak bone mass, most likely because they do not give sufficient weight to foods and nutrients important to bone health. We recommend the development of a diet pattern index that better predicts bone mass measures.

Parallel multispot smFRET analysis using an 8-pixel SPAD array

Single-molecule Förster resonance energy transfer (smFRET) is a powerful tool for extracting distance information between two fluorophores (a donor and acceptor dye) on a nanometer scale. This method is commonly used to monitor binding interactions or intra- and intermolecular conformations in biomolecules freely diffusing through a focal volume or immobilized on a surface. The diffusing geometry has the advantage to not interfere with the molecules and to give access to fast time scales. However, separating photon bursts from individual molecules requires low sample concentrations. This results in long acquisition time (several minutes to an hour) to obtain sufficient statistics. It also prevents studying dynamic phenomena happening on time scales larger than the burst duration and smaller than the acquisition time. Parallelization of acquisition overcomes this limit by increasing the acquisition rate using the same low concentrations required for individual molecule burst identification. In this work we present a new two-color smFRET approach using multispot excitation and detection. The donor excitation pattern is composed of 4 spots arranged in a linear pattern. The fluorescent emission of donor and acceptor dyes is then collected and refocused on two separate areas of a custom 8-pixel SPAD array. We report smFRET measurements performed on various DNA samples synthesized with various distances between the donor and acceptor fluorophores. We demonstrate that our approach provides identical FRET efficiency values to a conventional single-spot acquisition approach, but with a reduced acquisition time. Our work thus opens the way to high-throughput smFRET analysis on freely diffusing molecules.

Fast and direct measurements of the electrical properties of graphene using micro four-point probes

We present measurements of the electronic properties of graphene using a repositionable micro four-point probe system, which we show here to have unique advantages over measurements made on lithographically defined devices; namely speed, simplicity and lack of a need to pattern graphene. Measurements are performed in ambient, vacuum and controlled environmental conditions using an environmental scanning electron microscope (SEM). The results are comparable to previous results for microcleaved graphene on silicon dioxide (SiO(2)). We observe a pronounced hysteresis of the charge neutrality point, dependent on the sweep rate of the gate voltage; and environmental measurements provide insight into the sensor application prospects of graphene. The method offers a fast, local and non-destructive technique for electronic measurements on graphene, which can be positioned freely on a graphene flake.

A randomized trial of punctuated antiretroviral therapy in Ugandan HIV-seropositive adults with pulmonary tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/μL

BACKGROUND

Optimal treatment of human immunodeficiency virus (HIV)-associated tuberculosis in patients with high CD4⁺ T-cell counts is unknown. Suppression of viral replication during therapy for tuberculosis may block effects of immune activation on T cells and slow HIV disease progression.

METHODS

We conducted a randomized trial in 214 HIV-infected patients with active tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/μL to determine whether 6 months of antiretroviral therapy given during tuberculosis treatment would improve clinical outcomes. Subjects were randomized to receive 6 months of abacavir-lamivudine-zidovudine concurrent with tuberculosis therapy or delayed antiretroviral therapy. Endpoints were CD4⁺ T-cell counts of < 250 cells/μL, AIDS, or death.

RESULTS

Intervention and comparison arms had similar median CD4⁺ counts (517 and 534 cells/μL, respectively) and HIV RNA levels (4.6 and 4.7 log₁₀ copies/μL, respectively). Viral suppression was achieved in 86% of patients allocated to intervention. Seventeen subjects (15.6%) in the intervention arm developed study outcome compared to 25 subjects (22.8%) in the comparison arm (P = .17). Grade 3 or 4 adverse events were less frequent in the intervention arm. By 2 months, 90% of subjects in both arms were culture-negative for tuberculosis.

CONCLUSIONS

Short-term antiretroviral therapy during tuberculosis treatment in patients with CD4⁺T-cell counts of >350 cells/μL was safe and associated with clinical benefits.

Endovascular treatment of carotid embolic occlusions has a higher recanalization rate compared with cardioembolic occlusions

BACKGROUND AND PURPOSE

Treatment of large artery cerebral occlusions is rapidly evolving. We hypothesized that patients with intracranial embolic occlusions secondary to an extracranial carotid artery stenosis or occlusion have a higher probability of successful endovascular recanalization compared with those with cardioembolic occlusions.

METHODS

We retrospectively reviewed the databases of three institutions (University of Pittsburgh Medical Center (UPMC), Michigan State University (MSU) and Cleveland Clinic Foundation (CCF)) for acute anterior circulation ischemic strokes treated with endovascular therapies from January 2006 to July 2008. After collection of demographic, radiographic and angiographic variables, two groups were identified: artery to artery embolic occlusions and cardioembolic/cryptogenic intracranial occlusions. We defined recanalization as TIMI 2 or 3 flow. A binary logistic regression model was constructed to determine which characteristics were unique to patients with carotid embolic occlusions.

RESULTS

A total of 207 patients were identified (UPMC=100, CCF=71, MSU=36) with a mean age of 69±11 years and mean NIHSS of 17±5. Of these, 157 (75%) were due to a cardiac or cryptogenic source and 50 (25%) were from a carotid embolic source. The use of multimodal therapy (OR 2.6 (1.2-5.6), p<0.009) and the presence of a carotid embolic intracranial occlusion (OR 3.6 (1.2-7.1), p<0.012) were associated with successful recanalization, while carotid terminus occlusions were associated with unsuccessful recanalization (OR 0.35 (0.18-0.68), p<0.002).

CONCLUSIONS

Patients with intracranial occlusions secondary to an extracranial carotid stenosis or total occlusion appear to have more successful recanalization rates when treated with endovascular therapy compared with those with cardioembolic occlusions.

Subcellular distribution of L-type calcium channel subtypes in rat hippocampal neurons

L-type calcium channels play an essential role in synaptic activity-dependent gene expression and are implicated in long-term alterations in synaptic efficacy underlying learning and memory in the hippocampus. The two principal pore-forming subunits of L-type Ca2+ channels expressed in neurons are the Ca(v)1.2 (alpha(1C)) or Ca(v)1.3 (alpha(1D)) subtypes. Experimental evidence suggests that calcium entry through Ca(v)1.2 and Ca(v)1.3 Ca2+ channels occurs in close proximity to key signalling molecules responsible for triggering signalling pathways leading to transcriptional responses. Determining the subcellular distribution of Ca(v)1.2 and Ca(v)1.3 L-type channels in neurons is clearly important for unravelling the molecular mechanisms underlying long-term alterations in neuronal function. In this study, we used immunogold-labelling techniques and electron-microscopy (EM) to analyse the subcellular distribution and density of both Ca(v)1.2 and Ca(v)1.3 Ca2+ channels in rat hippocampal CA1 pyramidal cells in vivo. We confirm that both Ca(v)1.2 and Ca(v)1.3 channel subtypes are predominantly but not exclusively located in postsynaptic dendritic processes and somata. Both Ca(v)1.2 and Ca(v)1.3 are distributed throughout the dendritic tree. However, the smallest (distal) dendritic processes and spines have proportionally more calcium channels inserted into their plasma membrane than located within cytoplasmic compartments indicating the potential targeting of calcium channels to microdomains within neurons. Ca(v)1.2 and Ca(v)1.3 Ca2+ channels are located at the postsynaptic density and also at extra-synaptic sites. The location of L-type Ca(v)1.2 and Ca(v)1.3 channels in distal dendrites and spines would thus place them at appropriate sites where they could initiate synapse to nucleus signalling.

Effect of AbGn-7, a glycotope-specific monoclonal antibody, on apoptosis in colon cancer cells and tumor growth in xenograft models

e15118

Background: While clinical benefit against colorectal cancer has been observed with therapeutic monoclonal antibodies such as bevacizumab, cetuximab and panituzumab, the death rate of advanced colorectal cancer remains high that warrants further development of more potent therapeutics. Methods: A cell-based immunization approach was used to generate monoclonal antibodies against targets expressed on human colorectal cancer cells. A chimeric monoclonal antibody, AbGn-7, was selected and evaluated for the potential clinical use to treat colorectal cancer. Results: Expression of AbGn-7 antigen: Carbohydrate competition assay demonstrated that AbGn-7 recognizes a Lewis-A-like carbohydrate antigen (AbGn-7 antigen). Immunohistochemical studies showed that AbGn-7 antigen is expressed in colorectal cancer tissue. No significant binding could be detected in non-tumor tissues except in the epithelia of GI track. Effector function of AbGn-7: AbGn-7 triggered dose-dependent apoptosis in COLO 205 colon cancer cell. In addition, AbGn-7 elicited potent complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) in a dose-dependent manner. Molecular mechanism of apoptosis induced by AbGn-7: Tunel assay, PARP cleavage assay as well as caspase inhibitor studies demonstrated that AbGn-7 induced apoptosis in COLO 205 colon cancer cells via a caspase-independent pathway. Xenograft study: AbGn-7 alone, or in combination with 5FU-Leucovorin, effectively inhibited the growth of COLO 205 xenograft in SCID mice and prolonged their survival. Conclusions: The results of the present study suggest that AbGn-7 is a potential candidate for effective treatment of colorectal cancer.

[Table: see text]

Phase IIb trial of fluorouracil, leucovorin, oxaliplatin, and paclitaxel (POF) compared with fluorouracil, feucovorin, and irinotecan (IF) as first-line treatment for advanced gastric cancer (AGC)

e15642

Background: Primary results of POF as 1st and 2nd line treatment for AGC have been presented at ASCO 2007 and 2008. We report here data on the feasibility and the toxicity of POF versus IF(Dank, et al, ASCO 2005) in 1st line treatment of AGC. Methods: Patients with previously untreated, advanced, unresectable, and histologically confirmed adenocarcinoma of the gastric or gastroesophageal junction were randomly assigned to POF or IF regiment. Treatment was continued until disease progressed, unacceptable toxicity, or patient choice. Results: 25 patients were entered in this study between March 2007 and July 2007: 13 in the POF group and 12 in the IF group. The median patient age was 55 years (range, 36 to 67 years), 18 were males and 7 were females. No complete response was observed. The response rate was 62.5% (POF) and 33.3% (IF) respectively. At a median follow-up of 285 days, 7(POF) versus 6(IF) patients were still alive. Hematological toxicity was the most frequent toxicity in both groups. Grade 3 to 4 neutropenia were 38.5% (POF) versus 8.3% (IF). Diarrhea was found 0% and 8.3% in POF and IF group respectively. No grade 3 peripheral neurotoxicity was observed. Conclusions: Compared with IF regiment, POF could also be used as first-line treatment for AGC with acceptable safety profile, good efficacy, and more encouraging results.

No significant financial relationships to disclose.

Nutrition and children's respiratory health in Guangzhou, China

OBJECTIVE

To investigate the role of nutrition in children's respiratory health in subjects participating in a study on air pollution and respiratory health.

STUDY DESIGN

Cross-sectional survey.

METHODS

The relationships between consumption of fresh fruit, vegetables and milk and pulmonary function (forced expiratory volume in 1 s, FEV(1)) and respiratory symptoms (phlegm with cold, phlegm without cold, cough with cold, and cough without cold) were examined in 2228 children (age 10.07+/-0.86 years) in Guangzhou, China.

RESULTS

A positive association was found between consumption of leafy vegetables and lung function in children. Subjects with the highest consumption of leafy vegetables had significant higher FEV(1) values than subjects who ate leafy vegetables less than once per week (1.68 l vs 1.56 l; P=0.047). Children with high consumption of fresh fruit and milk had higher lung function values than children with low consumption, although the differences were not statistically significant. Milk consumption was a protective factor for phlegm with cold, cough with cold, and cough without cold [odds ratio (OR) 0.62, 95% confidence interval (CI) 0.39-0.97; OR 0.53, 95% CI 0.36-0.79; OR 0.43, 95% CI 0.21-0.92, respectively, in the highest intake group]. Consumption of vegetables was a protective factor for cough with cold (P for trend=0.003) and cough without cold (P for trend=0.028). Consumption of fresh fruit was marginally associated with reduced prevalence of respiratory symptoms.

CONCLUSIONS

This study suggests that dietary nutrients are important protective factors for children's respiratory health. Following-up these children may provide more evidence to confirm these associations.

Results of semimonthly 5-florouracil/leucovorin combined with paclitaxel and oxaliplatin in treatment of advanced gastric cancer (AGC)

15045

Background: At present there is still no standard chemotherapy regimen for AGC, the progress of AGC exhibits a pessimistic result with a median survival of less than 9 months. The purpose of this trial was designed to enhance the treatment efficacy for AGC by using semimonthly FU/LV combined with paclitaxel and oxaliplatin. Methods: Patients chosen with histologically proven diagnosis of adenocarcinoma of the stomach or gastroesophageal junction, locally advanced (i.e., unresectable) or metastatic and measurable disease. The chemotherapy regimen was comprised of a 3-hour infusion of 135 mg/m2 of paclitaxel followed by oxaliplatin 85 mg/m2 and LV 400 mg/m2, administered simultaneously as a 2-hour infusion, then continued a 46-hour infusion of FU 2.4 g/m2 using an ambulatory pump. Treatment was continued until disease progressed, unacceptable toxicity, or patient choice. The primary endpoint was response rate. Results: Twenty-seven patients were enrolled onto this study in our center between September 19, 2005 and December 25, 2006. The median patient age was 51 years (range, 28 to 66 years), 21 were males and 6 were females. All patients received the chemotherapy between at least two cycles and maximum eight cycles with a median of three. Four CRs of 27 enrolled patients, fifteen PRs and eight SDs were observed. Nineteen patients were chemonaive within enrolled patients: Four CRs, eleven PRs. At a median follow-up of 8.7 months, the median survival was 6.8 months. Frequent grade 3 to 4 toxicities were: neutropenia (37.0%), stomatitis (7.4%), nausea (7.4%), vomiting (7.4%), hepatic dysfunction (3.7%), paresthesia (18.5%). No treatment-related death occurred. Conclusion: Semimonthly FU/LV combined with paclitaxel and oxaliplatin appears to be of well efficacy and is well tolerated in patients with AGC. Currently, this regimen is being tested in the phase III trial involving patients with AGC on the basis of well result.

No significant financial relationships to disclose.

Selective method for the analysis of perchlorate in drinking waters at nanogram per liter levels, using two-dimensional ion chromatography with suppressed conductivity detection

The United States Environmental Protection Agency (EPA) collected drinking water occurrence data for perchlorate in the Unregulated Contaminant Monitoring Regulation (UCMR 1; 2001-2005) using EPA Method 314.0. To address the interest in increasing sensitivity and selectivity for the analysis of perchlorate, three new methods, EPA Methods 314.1, 331.0 and 332.0, were subsequently published by EPA for the analysis of perchlorate in drinking water. In 2006, an automated two-dimensional ion chromatography (2D-IC) method for measuring perchlorate with suppressed conductivity detection was developed. Two-dimensional IC is essentially an automated "heart-cutting", column concentration and matrix elimination technique. In the first dimension, a large sample volume is injected onto a first separation column and the separated matrix ions are diverted to waste while the analyte(s) of interest are selectively cut, trapped and concentrated in a concentrator column. In the second dimension, the contents from the concentrator column are eluted onto a second analytical column for separation and quantitation of the analyte(s) of interest. Incorporation of two columns with different affinities for the analyte(s) in a single analysis can provide comparable selectivity and superior sensitivity to a method using second column confirmation in a second separate analysis step. Use of this approach led to the development of a new, highly sensitive and selective 2D-IC, suppressed conductivity method with a Lowest Concentration Minimum Reporting Level (LCMRL) of 55 ng/L for perchlorate in drinking water samples. This new method has comparable sensitivity and selectivity and is simpler and more economical than IC-mass spectrometric (MS) or IC-MS-MS techniques. The method is now being prepared for publication as EPA Method 314.2.

Improving spatial signal homogeneity in MR 2D chemical shift imaging using outer volume saturation bands

Many endeavors of improving chemical shift imaging (CSI) techniques have been made during last two decades. Good examples of two-dimensional CSI and three-dimensional CSI can be found in the literature. However, clinical CSI using available sequences is still not satisfactory. The purpose of this study was to assess the effect of outer volume saturation bands on signal homogeneity in MR 2D chemical shift imaging. The 2D CSI scans were acquired using a point resolved spectroscopy (PRESS) CSI sequence on a phantom filled with brain metabolites. A single PRESS volume of interest was prescribed graphically. The acquisition matrix was 18x18 phase encodings over a 24-cm FOV. Identical acquisitions were obtained with and without outer-volume saturation bands. After initial acquisition was obtained, four more acquisitions were repeated for both studies with and without saturation bands. Identical five groups of voxels were compared for both studies. Standard deviations of metabolite ratios were calculated in each group for both studies. Spectra obtained without outer-volume saturation bands showed signal to noise gradient with higher concentration of signal within voxels at the center of the volume of interest. Outer volume saturation bands reduced this gradient. In general, standard deviations of metabolite ratios with saturation bands were smaller than those without saturation bands. Improved spatial homogeneity of spectra in voxels of CSI with saturation bands was obtained. Outer-volume saturation bands improve spatial signal homogeneity of chemical shift imaging.

The value of detecting anti-VZV IgG antibody in CSF to diagnose VZV vasculopathy

BACKGROUND

Factors that may obscure the diagnosis of varicella zoster virus (VZV) vasculopathy include the absence of rash before TIAs or stroke as well as similar clinical features and imaging, angiographic, and CSF abnormalities to those of other vasculopathies. Diagnosis relies on virologic confirmation that detects VZV DNA, anti-VZV IgG antibody, or both in the CSF.

METHODS

We reviewed our current 14 cases of patients diagnosed with VZV vasculopathy based on combined clinical, imaging, angiographic, or CSF abnormalities. All CSFs must have been tested for VZV DNA by PCR and for anti-VZV IgG antibody by enzyme immunoassay and found to be positive for either or both. Of the 14 subjects, 8 had a history of recent zoster, whereas 6 had no history of zoster rash before developing vasculopathy.

RESULTS

All 14 subjects (100%) had anti-VZV IgG antibody in their CSF, whereas only 4 (28%) had VZV DNA. The detection of anti-VZV IgG antibody in CSF was a more sensitive indicator of VZV vasculopathy than detection of VZV DNA (p < 0.001).

CONCLUSIONS

In varicella zoster virus (VZV) vasculopathy, the diagnostic value of detecting anti-VZV IgG antibody in CSF is greater than that of detecting VZV DNA. Although a positive PCR for VZV DNA in CSF is helpful, a negative PCR does not exclude the diagnosis of VZV vasculopathy. Only when the CSF is negative for both VZV DNA and anti-VZV IgG antibody can the diagnosis of VZV vasculopathy be excluded.

Elevated HIV seroprevalence and risk behavior among Ugandan TB suspects: implications for HIV testing and prevention

OBJECTIVES

Voluntary counseling and testing (VCT) for the human immunodeficiency virus (HIV) is recommended for persons treated for tuberculosis (TB). Opportunities to diagnose HIV may be missed by limiting HIV testing to only persons diagnosed with TB. Among TB suspects in Uganda, we determined HIV prevalence, risk behaviors, and willingness to refer family for VCT.

METHODS

Consenting adult patients presenting for evaluation at a referral TB clinic received same-day VCT. TB diagnosis data were abstracted from clinical records.

RESULTS

Among 665 eligible patients, 565 (85%) consented to VCT. Among these, 238 (42%) were HIV-positive. Of the HIV-infected patients, 37% had received a non-TB diagnosis. HIV seroprevalence was higher in patients with a non-TB diagnosis (49%) than those diagnosed with TB (39%) (P = 0.02). Fewer than 6% of HIV-infected patients reported always using condoms with sexual partners. The majority of patients (86%) reported being 'very willing' to refer family members for VCT.

CONCLUSIONS

Over 35% of HIV-infected cases in our population would have been undetected if HIV testing was limited to cases with diagnosed TB. The high HIV seroprevalence in both TB and non-TB cases merits HIV testing for all patients evaluated at TB clinics. HIV-infected TB suspects reporting high-risk behavior are at risk for HIV transmission, and should receive risk-reduction counseling.

A large noncoding RNA is a marker for murine hepatocellular carcinomas and a spectrum of human carcinomas

Tumor markers can facilitate understanding molecular cell biology of neoplasia and provide potential targets for the diagnosis and insight for intervention. We here identify a novel murine gene, hepcarcin (hcn), encoding a 7-kb mRNA-like transcript. The gene appears to be the murine ortholog of the human alpha gene, that is, MALAT-1. The gene and homologs lack credible open reading frames, consistent with a highly conserved large noncoding RNA (ncRNA). In all nodules of procarcinogen-induced murine hepatocellular carcinomas (HCCs) and human HCCs, expression was markedly elevated compared to the uninvolved liver. Quantitative analyses indicated a 6-7-fold increased RNA level in HCCs versus uninvolved liver, advancing this as a molecule of interest. This ncRNA was overexpressed in all five non-hepatic human carcinomas analysed, consistent with a potential marker for neoplastic cells and potential participant in the molecular cell biology of neoplasia.

Induction of IRF-3 and IRF-7 phosphorylation following activation of the RIG-I pathway

The induction of type I interferon (IFN) and the development of the innate antiviral response are mediated by the activation of interferon regulatory factor (IRF)-3 and IRF-7 under the control of the non-canonical kinases TBK-1 and IKKepsilon. The initial sensing of infection by RNA viruses is mediated by the cytoplasmic, retinoic acid inducible gene I (RIG-I), via a Toll-like receptor (TLR) independent signaling pathway. In the present study, we identify key residues involved in IRF-3 and IRF-7 phosphorylation using TAP-tag purification of TBK-1 and IKKepsilon proteins. Based on the identification of an extended sequence motif--SxSxxxS--common to both IRF-3 and IRF-7, an IRF-7 pSer477/479 phosphospecific antibody was generated. Virus infection, TBK-1/IKKepsilon expression or co-expression of different signaling adaptors such as RIG-I, MAVS and TRIF, all stimulated pSer477/479 phosphorylation. Furthermore, the newly identified adaptor of the RIG-I pathway (MAVS/IPS-1/VISA/Cardif) was able to induce IRF and NF-kappaB dependent promoter activity as efficiently as the constitutively active form of RIG-I (DeltaRIG-I). Co-expression of the NS3/4A protease activity of hepatitis C virus however blocked MAVS-mediated gene activation in a dose dependent manner. These studies link RIG-I sensing of viral RNA to downstream kinase signaling and phosphorylation of IRF-3 and IRF-7 via the MAVS/IPS/VISA/Cardif adaptor.

An integrated microfluidic device for influenza and other genetic analyses

An integrated microfluidic device capable of performing a variety of genetic assays has been developed as a step towards building systems for widespread dissemination. The device integrates fluidic and thermal components such as heaters, temperature sensors, and addressable valves to control two nanoliter reactors in series followed by an electrophoretic separation. This combination of components is suitable for a variety of genetic analyses. As an example, we have successfully identified sequence-specific hemagglutinin A subtype for the A/LA/1/87 strain of influenza virus. The device uses a compact design and mass production technologies, making it an attractive platform for a variety of widely disseminated applications.