Diagnostic accuracy study of multiplex PCR for detecting tuberculosis drug resistance

OBJECTIVE

To study the diagnostic accuracy of a multiplex real-time PCR (Anyplex II MTB/MDR/XDR, Seegene, Corea) that detects Mycobacterium tuberculosis resistant to isoniazid (INH), rifampicin (RIF), fluoroquinolones (FLQ) and injectable drugs (kanamycin [KAN], amikacin [AMK] and capreomycin [CAP]) in isolates and specimens.

METHODS

One hundred fourteen cultured isolates and 73 sputum specimens were retrospectively selected. Results obtained with multiplex PCR were compared with those obtained with BACTEC. Discordant results between multiplex PCR and BACTEC were tested by alternative molecular methods.

RESULTS

Sensitivity and specificity of multiplex PCR for detecting drug resistance in isolates were 76.5% and 100%, respectively, for INH; 97.2% and 96.0%, respectively, for RIF; 70.4% and 87.9%, respectively, for FLQ; 81.5% and 84.8%, respectively, for KAN; 100% and 60%, respectively, for AMK, and 100% and 72.3%, respectively, for CAP. Sensitivity and specificity of Anyplex for detecting drug resistance in specimens were 93.3% and 100%, respectively, for INH; 100% and 100%, respectively, for RIF; 50.0% and 100%, respectively, for FLQ; and 100% and 94.4%, respectively, for both KAN and CAP. Among the discordant results, 87.7% (71/81) of results obtained with the multiplex PCR were concordant with at least one of the alternative molecular methods.

CONCLUSIONS

This multiplex PCR may be a useful tool for the rapid identification of drug resistant tuberculosis in isolates and specimens, thus allowing an initial therapeutic approach. Nevertheless, for a correct management of patients, results should be confirmed by a phenotypic method.

Don't be Half-Educated About Haff Disease in Louisiana

Cases of Haff disease, a syndrome of severe myalgia and rhabdomyolysis, have been reported after eating cooked fish in Europe and the US. A retrospective review of US cases was conducted to identify seafood vectors, describe presenting manifestations, and compare the Haff disease toxidrome with other seafood-borne toxidromes. Internet search engines were queried to identify all US reports of Haff disease. The case definition of Haff disease required cooked seafood ingestion history within 24 hours and markedly elevated serum creatine kinase (CK) with CK-muscle/brain (MB) fraction < 5 percent. Twenty-six cases of Haff disease were reported in the US over 30 years, 1984-2014, with spring-summer occurrences. The mean age of cases was 54.8 years without gender difference. Most cases (58 percent) followed consumption of cooked buffalo fish, Ictiobus cyprinellus, (n = 15); other cases followed consumption of boiled crayfish in Louisiana (n = 9) and baked salmon in North Carolina (n = 2). California and Louisiana accounted for most cases (n = 18, p = 0.012). Following mean incubation periods of eight hours; the most common presenting manifestations included vomiting, myalgia, muscle rigidity, chest pain mimicking myocardial infarction, diaphoresis, dyspnea, and brown urine indicating myoglobinuria. Most patients recovered within 2-5 days. Haff disease may follow the consumption of freshwater buffalo fish, freshwater crayfish, and saltwater Atlantic salmon. The bioconcentration of a new, unidentified heat-stable, freshwater and/or brackish/saltwater algal myotoxin in seafood, similar to palytoxin, is suspected of causing Haff disease. Experimental animals fed toxic buffalo fish developed rhabdomyolysis with myoglobinuria.

EEG functional connectivity is partially predicted by underlying white matter connectivity

Over the past decade, networks have become a leading model to illustrate both the anatomical relationships (structural networks) and the coupling of dynamic physiology (functional networks) linking separate brain regions. The relationship between these two levels of description remains incompletely understood and an area of intense research interest. In particular, it is unclear how cortical currents relate to underlying brain structural architecture. In addition, although theory suggests that brain communication is highly frequency dependent, how structural connections influence overlying functional connectivity in different frequency bands has not been previously explored. Here we relate functional networks inferred from statistical associations between source imaging of EEG activity and underlying cortico-cortical structural brain connectivity determined by probabilistic white matter tractography. We evaluate spontaneous fluctuating cortical brain activity over a long time scale (minutes) and relate inferred functional networks to underlying structural connectivity for broadband signals, as well as in seven distinct frequency bands. We find that cortical networks derived from source EEG estimates partially reflect both direct and indirect underlying white matter connectivity in all frequency bands evaluated. In addition, we find that when structural support is absent, functional connectivity is significantly reduced for high frequency bands compared to low frequency bands. The association between cortical currents and underlying white matter connectivity highlights the obligatory interdependence of functional and structural networks in the human brain. The increased dependence on structural support for the coupling of higher frequency brain rhythms provides new evidence for how underlying anatomy directly shapes emergent brain dynamics at fast time scales.

AID TB resistance line probe assay for rapid detection of resistant Mycobacterium tuberculosis in clinical samples

OBJECTIVES

To determine the sensitivity and specificity of AID TB Resistance line probe assay (AID Diagnostika, Germany) to detect Mycobacterium tuberculosis and its resistance to first- and second-line drugs in clinical samples using BACTEC 460TB as the reference standard.

METHODS

The test consists on three strips to detect resistance to isoniazid/rifampicin, fluoroquinolones/ethambutol, and kanamycin/amikacin/capreomycin/streptomycin, respectively. This test was performed on 65 retrospectively selected clinical samples corresponding to 32 patients.

RESULTS

A valid result was obtained for 92.3% (60/65), 90.8% (59/65) and 78.5% (51/65) of the samples tested, considering the three strips, respectively. Global concordance rates between AID and BACTEC for detecting resistance to isoniazid, rifampicin, fluoroquinolones, ethambutol, kanamycin/capreomycin and streptomycin were 98.3% (59/60), 100% (60/60), 91.5% (54/59), 72.9% (43/59), 100% (51/51) and 98.0% (50/51), respectively. Regarding the discordant results obtained between AID and BACTEC, the alternative molecular methods performed (GenoType MTBDRplus, GenoType MTBDRsl [Hain Lifescience, Germany] and/or pyrosequencing) confirmed the genotypic result in 90.9% (20/22) of the cases.

CONCLUSIONS

AID line probe assay is a useful tool for the rapid detection of drug resistance in clinical samples enabling an initial therapeutic approach. Nevertheless, for a correct management of drug resistant tuberculosis patients, molecular results should be confirmed by a phenotypic method.

Loop versus end colostomy reversal: has anything changed?

PURPOSE

Though primary repair of colon injuries is preferred, certain injury patterns require colostomy creation. Colostomy reversal is associated with significant morbidity and healthcare cost. Complication rates may be influenced by technique of diversion (loop vs. end colostomy), though this remains ill-defined. We hypothesized that reversal of loop colostomies is associated with fewer complications than end colostomies.

METHODS

This is a retrospective, multi-institutional study (four, level-1 trauma centers) of patients undergoing colostomy takedown for trauma during the time period 1/2006-12/2012. Data were collected from index trauma admission and subsequent admission for reversal and included demographics and complications of reversal. Student's t test was used to compare continuous variables against loop versus end colostomy. Discrete variables were compared against both groups using Chi-squared tests.

RESULTS

Over the 6-year study period, 218 patients underwent colostomy takedown after trauma with a mean age of 30; 190 (87%) were male, 162 (74%) had penetrating injury as their indication for colostomy, and 98 (45%) experienced at least one complication. Patients in the end colostomy group (n = 160) were more likely to require midline laparotomy (145 vs. 18, p < 0.001), had greater intra-operative blood loss (260.7 vs. 99.4 mL, p < 0.001), had greater hospital length of stay (8.4 vs. 5.5 days, p < 0.001), and had more overall complications (81 vs. 17, p = 0.005) than patients managed with loop colostomy (n = 58).

CONCLUSIONS

Local takedown of a loop colostomy is safe and leads to shorter hospital stays, less intra-operative blood loss, and fewer complications when compared to end colostomy.

Meningococcal carriage prevalence in university students, 1824 years of age in Santiago, Chile

INTRODUCTION

Neisseria meningitidis invasive disease is a major public health problem. Pharyngeal carriage is considered a prerequisite for invasive infection. Prevalence reaches 10% in general population and up to 30% in the 20-24 years age group. The aim of this study was to asses pharyngeal carriage prevalence in healthy subjects aged 18-24 years, and as secondary endpoints evaluate known risk factors, to identify serogroups and sequence in the isolated strains.

METHODS

Cross-sectional study in 500 healthy subjects; students from Universidad de Chile aged 18-24 years, Santiago, Chile, October 2012. Each subject underwent a risk factor survey prior to throat culture sampling. Samples were processed in one central Microbiology Laboratory of Hospital Luis Calvo Mackenna and serogrouping and sequencing was performed at Instituto de Salud Pública de Chile.

RESULTS

We obtained throat samples from 500 healthy subjects, 20 (4%) positive for N. meningitidis. Of positive strains 20% were serogroup B, 15% W and the rest non groupable. The median age was 20 years, 50% were men. Of the risk factors evaluated, 24% were current smokers, 16% shared a room, 72% had kissed someone during the last month, 64% had gone to pub and 76% had consumed alcohol in the same period of time.

DISCUSSION

Literatures meningococcal carriage prevalence reaches up to 30% in people aged 18-24 years. Prevalence in our study was 4%. Different interpretations could be given; one could be the absence of overcrowding in our students because of the lack of dorms in our scholar system and also the characteristics of our enrolled group.

CONCLUSIONS

Our results suggest the necessity to extend the study to other age groups and to other cities, to better understand the Chilean reality, as well as others regions of America, considering that these results cannot be extrapolated to another countries.

GaInN/GaN Multi-Quantum Well Laser Diodes Grown by Low-Pressure Metalorganic Chemical Vapor Deposition

We report the growth, fabrication and characterization of GaInN/GaN multi-quantum well lasers grown on (00·1) sapphire substrates by low pressure metalorganic chemical vapor deposition. The threshold current density of a 1800 μm long cavity length laser was 1.4 kA/cm2 with a threshold voltage of 25 V. These lasers exhibited series resistances of 13 and 14 Ω at 300 and 79 K, respectively.

Past and future of a century old Citrus tristeza virus collection: a California citrus germplasm tale

Citrus tristeza virus (CTV) isolates collected from citrus germplasm, dooryard and field trees in California from 1914 have been maintained in planta under quarantine in the Citrus Clonal Protection Program (CCPP), Riverside, California. This collection, therefore, represents populations of CTV isolates obtained over time and space in California. To determine CTV genetic diversity in this context, genotypes of CTV isolates from the CCPP collection were characterized using multiple molecular markers (MMM). Genotypes T30, VT, and T36 were found at high frequencies with T30 and T30+VT genotypes being the most abundant. The MMM analysis did not identify T3 and B165/T68 genotypes; however, biological and phylogenetic analysis suggested some relationships of CCPP CTV isolates with these two genotypes. Phylogenetic analysis of the CTV coat protein (CP) gene sequences classified the tested isolates into seven distinct clades. Five clades were in association with the standard CTV genotypes T30, T36, T3, VT, and B165/T68. The remaining two identified clades were not related to any standard CTV genotypes. Spatiotemporal analysis indicated a trend of reduced genotype and phylogenetic diversity as well as virulence from southern California (SC) at early (1907-1957) in comparison to that of central California (CC) isolates collected from later (1957-2009) time periods. CTV biological characterization also indicated a reduced number and less virulent stem pitting (SP) CTV isolates compared to seedling yellows isolates introduced to California. This data provides a historical insight of the introduction, movement, and genetic diversity of CTV in California and provides genetic and biological information useful for CTV quarantine, eradication, and disease management strategies such as CTV-SP cross protection.

Seasonal primary amebic meningoencephalitis (PAM) in the south: summertime is PAM time

Primary amebic meningoencephalitis (PAM), a typically fatal, free-living amebic infection of the central nervous system (CNS), is caused by the thermophilic, freshwater protozoan, Naegleria fowleri. More than 145 cases of PAM have been reported worldwide, with most reported cases in the United States (US). Since annual PAM case clusters in the US and worldwide have demonstrated recent increases over background cases, the objectives of this investigation included (1) an epidemiological and statistical analysis of a 2007 cluster of six PAM cases in the southern US, nested in a retrospective review of 121 confirmed US cases of PAM over the period, 1937 to 2007; and (2) a statistical analysis of all existing demographic, temporal, and behavioral risk factors for PAM. Significant risk factors for PAM in the United States included male sex and warm recreational freshwater exposures in seasonal patterns (July - August) in southern tier states, including Louisiana. Although there have been a few recent survivors of PAM treated with combinations of intensive critical care, antifungals, and synergistic antibiotics, case fatality rates for PAM remain very high. PAM is best prevented by combinations of public health educational and behavioral modification strategies. Further investigations will be required to determine the significance of freshwater wakeboarding as a significant risk factor for PAM and to determine any dose-response effects of global warming on rising freshwater temperatures and the growth of aquatic Naegleria fowleri.

Dengue virus identification by transmission electron microscopy and molecular methods in fatal dengue hemorrhagic fever

Dengue virus is the most significant virus transmitted by arthropods worldwide and may cause a potentially fatal systemic disease named dengue hemorrhagic fever. In this work, dengue virus serotype 4 was detected in the tissues of one fatal dengue hemorrhagic fever case using electron immunomicroscopy and molecular methods. This is the first report of dengue virus polypeptides findings by electron immunomicroscopy in human samples. In addition, not-previously-documented virus-like particles visualized in spleen, hepatic, brain, and pulmonary tissues from a dengue case are discussed.

Clinical validation of the European Panel on the Appropriateness of Gastrointestinal Endoscopy (EPAGE) II criteria in an open-access unit: a prospective study

BACKGROUND AND STUDY AIMS

The European Panel on the Appropriateness of Gastrointestinal Endoscopy (EPAGE I) criteria were recently updated (EPAGE II), but no prospective studies have used these criteria in clinical practice. The aim of the current study was to validate the EPAGE II criteria in an open-access endoscopy unit.

PATIENTS AND METHODS

A prospective observational study was conducted in an open-access endoscopy unit at a tertiary care referral center. Consecutive outpatients (n = 1004; mean age 58.9 ± 13.1 years; 45 % men) were referred for diagnostic colonoscopy between September 2009 and February 2010. The appropriateness of colonoscopy was assessed based on EPAGE II criteria, and the relationship between appropriateness and both referral doctor and detection of significant lesions was examined. The effectiveness of EPAGE II criteria in assessing appropriateness was measured by means of sensitivity, specificity, and positive and negative predictive values for detecting significant lesions.

RESULTS

Colonoscopic cecal intubation was achieved in 956 patients (95.2 %). Most referral doctors were gastroenterologists (58.0 %) and the most common indication was colorectal cancer (CRC) screening (35.2 %). EPAGE II criteria were applicable in 968 patients (96.4 %); of these patients, the indication was appropriate in 778 (80.4 %), inappropriate in 102 (10.5 %), and uncertain in 88 (9.1 %). Patients with appropriate or uncertain indications based on EPAGE II criteria had more relevant endoscopic findings than those with inappropriate indications (38.8 % vs. 24.5 %; OR 1.95, 95 %CI 1.22 - 3.13; P < 0.005). Sensitivity and negative predictive value of EPAGE II criteria for detecting significant lesions were 93.1 % (95 %CI 90 % - 96 %) and 75.5 % (95 %CI 67 % - 84 %), respectively, whereas for advanced neoplastic lesions these values were 98.0 % (95 %CI 95 % - 100 %) and 98.0 % (95 % CI 95 % - 100 %), respectively. Adherence to EPAGE II recommendations was an independent predictor of finding a significant lesion (OR 1.93, 95 %CI 1.20 - 3.11; P = 0.007).

CONCLUSIONS

EPAGE II is a simple, valid score for detecting inappropriate colonoscopies in clinical practice.

Donor-derived organ transplant transmission of coccidioidomycosis

Coccidioidomycosis in solid organ transplant recipients most often occurs as a result of primary infection or reactivation of latent infection. Herein, we report a series of cases of transplant-related transmission of coccidioidomycosis from a single donor from a non-endemic region whose organs were transplanted to 5 different recipients. In all, 3 of the 5 recipients developed evidence of Coccidioides infection, 2 of whom had disseminated disease. The degree of T-cell immunosuppression and timing of antifungal therapy initiation likely contributed to development of disease and disease severity in these recipients. This case series highlights the importance of having a high index of suspicion for Coccidioides infection in solid organ transplant recipients, even if the donor does not have known exposure, given the difficulties of obtaining a detailed and accurate travel history from next-of-kin.

Preliminary assessment of Treponema pallidum-specific IgM antibody detection and a new rapid point-of-care assay for the diagnosis of syphilis in human immunodeficiency virus-1-infected patients

The aims of the study were to assess whether Treponema pallidum-specific IgM may provide a useful marker of infectious syphilis in human immunodeficiency virus (HIV)-infected patients, and to compare the performance of a prototype IgM-rapid point-of-care test (PoCT) with a standard IgM-enzyme immunoassay (EIA). Twenty samples from HIV-infected patients with untreated syphilis (n = 4 primary syphilis, n = 11 secondary and n = 5 early latent) and 51 follow-up samples at three, six or 12 months after treatment were tested for the presence of IgM with the Mercia-EIA (Microgen Bioproducts Ltd, Camberley, UK) and a prototype PoCT (Select Vaccines Ltd, Melbourne, Australia). Although sample numbers were small, IgM detection by EIA appears to be a reliable marker for untreated syphilis in HIV-infected patients with primary (4/4 IgM-positive) or secondary syphilis (10/11 IgM-positive, 1/11 equivocal). After treatment, IgM was no longer detected after three months in the majority of patients (87%) and was either negative or equivocal in all patients after six and 12 months. The overall sensitivity of the IgM-PoCT was 82% and varied with clinical stage, being highest in secondary (10/10 EIA positives) but lower in primary (2/4 EIA positives) and early latent syphilis (2/3 EIA positives). Overall specificity was 95%. Rapid detection of IgM would enable clinicians to distinguish between past-treated and infectious syphilis and allow for diagnosis and treatment in a single visit.

Calculation of Young's modulus value by means of AFM

In the last years, Atomic Force Microscopy (AFM) has become a powerful tool not only to study the surface morphology but also the nanomechanics of all kind of samples. In this paper, the applicability of this technique is reviewed and its basic aspects of operation, advantages and drawbacks of using the AFM probe as a picoindenter (Force Spectroscopy mode, FS-AFM) are discussed. The patents concerning picoindentation measurements are discussed in the text and special attention is paid to measurements performed on hard materials as ceramics, as they have not been as thoroughly reviewed in the literature as in the case of soft matter. The possibilities of AFM in the nanomechanics field include the quantitative determination of the Young's modulus (E) and the transition force from elastic to plastic deformation regimes, the measurement of adhesion forces and deformation mechanisms while applying vertical forces in the range from tens of pN to μN.

Stem Rot of Branched Broomrape (Orobanche ramosa) Caused by Sclerotium rolfsii in Chile

Branched broomrape is a holoparasitic weed present in some areas of central and southern Chile (33°S to 38°S), which is often found parasitizing tomato and tobacco crops. During an extensive survey conducted in different tomato-growing areas during the summer of 2010, branched broomrape plants with stem rot symptoms were detected in a commercial tomato crop located in the central zone (34°14'S, 71°1'W). Rotten stems were observed with white mycelia and approximately 1-mm-diameter spherical sclerotia on affected tissue below the soil surface. Parasitized tomato plants showed no symptoms. Sclerotia were taken directly from affected stems with a dissecting needle under a stereoscopic microscope in a flow chamber and placed on potato dextrose agar (PDA) medium. Germinating sclerotia consistently produced colonies similar to Sclerotium rolfsii with new sclerotia formed within 6 to 7 days. Mycelia produced hyphal clamp connections under the light microscope (2). DNA was extracted from one fungal culture. The ITS1 region, 5.8S rRNA gene, and the ITS2 region of the nuclear-encoded ribosomal RNA gene were amplified with primers ITS1 and ITS4 (4). The sequence was deposited in GenBank (Accession No. HM222638) and showed ≥99% identity values with sequences of similar regions from Athelia rolfsii (anamorph S. rolfsii; Accession Nos. AB075304, DQ0595578, AF499018, and AB075305). Different pathogenicity tests were performed. Inoculum was prepared by placing mycelia plugs from a PDA-grown, 6-day-old colony in a flask with sterilized wheat seeds and incubated for 2 weeks. Three Orobanche plants, each one with 10 to 15 shoots at different aerial stages (starting emergence, flowering, and formed capsules) were gently planted separately in 35-cm pots. Inoculum (10 g per pot) was placed in the soil surrounding the plants. One pot was used as a control. Forty-five-day-old tomato and tobacco plants were additionally inoculated by a similar procedure. After 12 days, inoculated Orobanche plants showed reduced vigor and stem decay. After 9 days, tomato and tobacco plants showed wilt. In all cases, the fungus was reisolated on PDA from all inoculated plants. To our knowledge, this is the first report of S. rolfsii on O. ramosa (1). A previous report of S. rolfsii parasitizing O. cernua has also been made (3). The high susceptibility of tomato and tobacco plants to this isolate of S. rolfsii precludes the use of this pathogen as a biological control agent against broomrape. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved May 14, 2010, from http://nt.ars-grin.gov/fungaldatabases . (2) Z. K. Punja and A. Damiani. Mycologia 88:694, 1996. (3) C. A. Raju et al. Phytoparasitica 23:235, 1995. (4) T. J. White et al. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.

In Silico Analysis of Breast Cancer Transcriptome Libraries Distinguish Tumor Subclasses

BackgroundBreast carcinoma is one of the most common causes of cancer related death worldwide. However marked differences in outcomes may reflect variation in diagnostic, staging and treatment. Serial Analysis of Gene Expression (SAGE) is a comprehensive profiling method that allows for global, unbiased and quantitative characterization of transcriptomes. A major advantage of SAGE is that once normalized it is possible to directly compare the levels of tags (short nucleotide sequences) generated by a single experiment with any other compatible available.MethodsTo gain an insight on the relationship between breast cancer transcriptomes and the disparate outcomes observed, we retrieve 18 SAGE libraries (4 Normal breast tissues, 11 primary breast tumors and 3 breast cancer metastatic tissues) from Cancer Genome Anatomy Project (CGAP). Data were analyzed by Correspondence Analysis (COA), Hierarchical clustering, Support Tree (ST) and Significance Analysis for Microarray (SAM) using TMEV software (tm4.org). Tags assignment to genes was performed by CGAP, and pathways analysis by FatiGO (babelomics.bioinfo.cipf.es).ResultsThe selection process to find SAGE tags that were consistently expressed in all normal, tumor and metastatic libraries resulted in 2,437 tags. COA shows clear separation between normal and metastatic libraries. These results were confirmed by Support Tree using the Pearson Correlation and Average Linkage (Fig 1). Interestingly, the 11 tumor SAGE libraries consisted of two heterogeneous groups, one similar to metastatic libraries (cases 1, 2, 8, 9, 10, 11) and the other to normal libraries (cases 3, 4, 5, 6, 12). Next, to identify SAGE tags differentially expressed between these two different groups of tumors, we performed SAM (delta value = 1.38, fold discovery rate = 0, 1001 unique permutations and fold change = 10). This approach revealed 59 (6%) tags differentially expressed across both tumor libraries. Among these 59 tags, 3 were up-regulated in tumors associated to normal libraries (normal-like tumors) and 56 were up-regulated in tumors associated to metastatic libraries (metastatic-like tumors). Next, tag to gene association identified 48 genes. Pathway analysis of these 48 genes revealed that tumors similar to normal libraries were characterized by activation of apoptosis and protein kinase pathways (JUND, GADD45B) and tumors similar to metastatic libraries were associated with response to extracellular stimulus, cell surface receptor linked signal transduction, Wnt receptor signaling pathway, cell cycle, phosphorylation, mRNA metabolic process, cell proliferation, regulation of cell proliferation, DNA replication, peptide metabolic process, signal peptide processing (NDUFB2, RPS27A, COX6B1, RBBP4, NDUFB9). These pathways may be implicated in outcomes to drug therapies.ConclusionsComprehensive analysis 2,437 tags from whole transcriptomes of primary breast cancer tissue compared with normal breast tissue and breast cancer metastatic tissues revealed that clinically disparate outcomes could be linked to a relatively small number of transcripts, since 6% (59 tags) were responsible of the differences across the normal-like and the tumor-like breast tumors.Supported FONDECYT 1080563 – Government of Chile

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1165.

Use of frequency analysis on the ECG for the prognosis of low energy cardioversion treatment of atrial fibrillation

Electric cardioversion is the most effective therapy for restoring sinus rhythm in patient with atrial fibrillation (AF), however, there is not a guiding criteria for advising on when and in whom it will be successful. The objective of this study was to employ frequency analysis on the surface electrocardiogram (ECG) to predict the outcome of low energy internal cardioversion in patients with AF. Thirty nine patients with AF, for elective DC cardioversion were included in this study. One catheter was positioned in the right atrial appendage and another in the coronary sinus. A voltage step-up protocol (50-300 V) was used for patient cardioversion. Prior to shock delivery, residual atrial activity signal (RAAS) was derived from 60 seconds of surface ECG from defibrillator pads, by bandpass filtering and ventricular activity (QRST) cancellation. Dominant atrial fibrillatory frequency (DAFF) was estimated from the RAAS power spectrum as the dominant frequency within the 3-12 Hz band. DAFF was calculated from whole 60 seconds segment (DAFF_L) and from the finals 10 seconds segment (DAFF_S) of the RAAS. Lower DAFF_L and DAFF_S were found in successfully cardioverted patients than in those nonsuccessful ones, with energy < or =3 and < or =6 joules. Therapy result (employing 3J or less) was predicted in 35/39 (89.7%) patients with DAFF_L=5.40Hz, and DAFF_L was > or =5.75Hz in a 100% of noncardioverted patients. In conclusion, frequency analysis of the RAAS could be useful for predicting success of low energy internal cardioversion of patients with atrial fibrillation.

Comparison of two immunochromatographic assays and the indirect immunofluorescence antibody test for diagnosis of Trypanosoma cruzi infection in dogs in south central Louisiana

Two rapid tests evaluated in dogs considered to be of high risk of infection with the Chagas parasite Trypanosoma cruzi using two immunochromatographic assays: Trypanosoma Detect for canine, InBios, Seattle, WA and CHAGAS STAT-PAK assay, Chembio Diagnostic Systems, Medford, NY, in south central Louisiana. For this purpose a serological survey was carried out in a total of 122 dogs and a serum bank was created. These 122 animals were first tested by IFAT that was used as the standard test. From the serum bank 50 samples were tested using the two rapid Chagas assays and results compared to the standard test IFAT. The serological survey using IFAT showed a prevalence of T. cruzi infection in 22.1% of the tested dogs. In the immunochromatographic assays, 13 and 11 animals were positive on rapid assay: Trypanosoma Detect for canine, InBios and CHAGAS STAT-PAK, Chembio Diagnostic Systems, respectively compared to 11 positive by IFAT. These two immunochromatographic tests have shown high susceptibility and specificity compared to our standard method IFAT. The rapid, easy and accurate screening assays used in conjunction with confirmatory tests, would be an excellent tool for veterinarians to diagnose T. cruzi infection. Early detection of T. cruzi infection may prevent complications through an effective treatment. Greater awareness by veterinarians of the risk, clinical findings, history along with diagnostic methods will contribute greatly to an understanding of the true prevalence of Chagas disease in dogs in Louisiana.

A correlative study of clinical and histological findings of revision hip arthroplasty for rheumatoid arthritis and inflammatory joint disease

OBJECTIVE

Primary hip arthroplasty in rheumatoid arthritis (RA) and other forms of inflammatory joint disease (IJD) is generally thought to be associated with a less favourable outcome in terms of implant survival and other complications. Whether the duration of implant survival correlates with the degree of rheumatoid-like inflammatory changes in periprosthetic tissues is uncertain.

METHODS

Histopathological changes in periprosthetic tissues obtained following revision surgery of 34 total hip replacements on 27 patients with IJD (RA 18 cases: ankylosing spondylitis three cases; juvenile chronic arthritis six cases) were examined.

RESULTS

A heavy diffuse lymphocyte and plasma cell infiltrate +/- lymphoid aggregates was noted in 29% of cases in whom the mean implant survival was 5.6 years (range: 2-8 years). Where little or no lymphocytic infiltrate was noted in periprosthetic tissues, the mean implant survival was 8.6 years (range: 1-17 years). Revision arthroplasty was not undertaken for early or late infection of a primary hip replacement.

CONCLUSIONS

Our findings indicate that implant survival is less in those cases where there is a heavy lymphocyte and plasma-cell infiltrate in periprosthetic tissues. These findings suggest that the presence of a heavy chronic inflammatory-cell infiltrate in periprosthetic tissues is likely to be a contributory factor in causing early implant failure in RA.

High-Density Transcranial Direct Current Stimulation (HD-tDCS): Hardware Interface

Transcranial Direct Current Stimulation (tDCS) is a non-invasive procedure where a weak electrical current (260 μA to 2 mA) is applied across the scalp to modulate brain function. tDCS has been applied for therapeutic purposes (e.g., addiction, depression, mood and sleep disorders) as well as cognitive performance enhancement (e.g., memory consolidation, motor learning, language recall). Despite safety and cost advantages, the developments of tDCS therapies have been restricted by spatial targeting concerns using existing two-channel systems. We have developed novel technology for High-Density tDCS (HD-tDCS) that improves spatial focality. Our hardware interface integrates a multichannel stimulating guide with existing two channel tDCS stimulators, and can be configured to target specific brain regions using computational models of current flow and multichannel array accessories. The hardware interface provides real time stimulation quality and safety feedback, and is designed to be MRI and TMS compatible. An electrical “tickle” feature enables skin pre-conditioning to minimize sensation. The full system includes the hardware interface, cable assemblies, head gear, tDCS electrodes, tDCS gel, and electrode adaptors. The head gear allows fixing the electrode adaptors over cortical targets using conventional EEG electrode coordinates. The electrode adaptors “fin” design, tDCS gel composition, and electrode shape are optimized to reduce sensation during direct current stimulation with 2 mA for up to 22 minutes. A five electrode system (4×1-C1), for implementing optimally focal “4×1 ring configuration” protocols, and an 8 electrode system (4×4-S1), that can be configured for “4×4 cortical strip stimulation”, are available. The entire system is robust, intuitive, and ultimately adaptable for home use. Our HD-tDCS system allows non-invasive, safe, and targeted modulation of selected cortical structures for electrotherapies that are individualized as well as optimized for a range of therapeutic applications.

High-Density Transcranial DC Stimulation (HD-tDCS): Targeting Software

Transcranial Direct Current Stimulation (tDCS) is a non-invasive procedure where a weak electrical current (260 μA to 2 mA) is applied across the scalp to modulate brain function. tDCS has been applied for therapeutic purposes (e.g., addiction, depression, mood and sleep disorders) as well as cognitive performance enhancement (e.g., memory consolidation, motor learning, language recall). Despite safety and cost advantages, the developments of tDCS therapies have been restricted by spatial targeting concerns using existing two-channel systems. We have developed novel technology for High-Density tDCS (HD-tDCS) that improves spatial focality. To determine optimal stimulation electrode configurations, based on application specific constraints, we developed a HD-tDCS targeting software. High resolution (gyri/sulci precise) MRI derived finite element (FE) human head models are generated by segmenting grey matter, white matter, CSF, skull, muscle, fatty tissue, eyes, blood vessels, scalp, etc. The models comprised >10 million elements with >15 million degrees of freedom. The induced cortical electric field/current density values are calculated; activation of either radially and tangentially oriented neuronal structures are considered. Our HD-tDCS hardware (4×1-C1, 4×4-S1) currently supports the ‘4×1-Ring’ and the ‘4×4-Strip’ electrode configurations. The peak cortical electric field was matched to ‘conventional’ large rectangular-pad tDCS stimulation; however, the spatial focality was significantly enhanced by 4×1 configuration. Using patient specific head models, our software interface allows simple and rapid screening of stimulation electrode configurations. After selecting a target region, clinicians can customize the electrode configuration to balance: 1) cortical surface and brain depth stimulation focality; 2) total applied current/voltage; and 3) electrode/scalp current density. Our HD-tDCS system allows non-invasive, safe, and targeted modulation of selected cortical structures for electrotherapies that are individualized as well as optimized for a range of therapeutic applications.

Sexual risk behaviours and HIV seroprevalence among male sex workers who have sex with men and non-sex workers in Campinas, Brazil

OBJECTIVES

To compare population-based prevalence estimates of sexual risk behaviours and HIV seroprevalence of male sex workers who have sex with men (MSM) and those not engaged in sex work in Campinas, Brazil.

METHODS

MSM (n = 658) were recruited for a cross-sectional study through respondent-driven sampling. Audio-assisted computer self-interview was used to collect information on sexual behaviours and HIV testing (optional) was performed. Population-based prevalence estimates with 95% CI of characteristics and behaviours of MSM sex workers and non-sex workers are reported.

RESULTS

One-quarter reported ever receiving payment for sex and 14.8% (95% CI 11.1 to 19.0) had been paid in the previous 2 months; most exclusively with men. MSM sex workers were significantly more likely than non-sex workers to report being transgendered (40.5% vs 8.1%), to practise unprotected receptive (22.4% vs 4.6%) and insertive (20.5% vs 5.0%) anal intercourse with > or =2 male partners and to have unprotected vaginal sex with women (22.7% vs 5.6%). MSM sex workers experienced significantly greater rates of psychological abuse (80.9% vs 58.4%) and physical abuse (48.2% vs 15.2%).

CONCLUSIONS

MSM sex workers have higher sexual risk behaviours as well as social vulnerabilities than the general population of MSM. HIV/sexually transmitted infection prevention efforts should be targeted to this riskier subgroup. Programmes should be transgender sensitive, should recognise that MSM sex workers have sex with men and women and address other factors that influence risk, such as homophobic abuse.

Nonlinear analysis of the ECG during atrial fibrillation in patients for low energy internal cardioversion

The goal of this study was to investigate the usefulness of nonlinear analysis in determining the success of low energy internal cardioversion (IC) in patients with atrial fibrillation (AF). Nonlinear analysis has previously been used for characterizing AF patterns, and spontaneous termination in its paroxysmal form. However, the relationship between the probability to restore sinus rhythm by IC and quantitative nonlinear analysis based electrocardiographic (ECG) markers has not been explored before. Thirty nine patients with AF, for elective DC cardioversion at the Royal Victoria Hospital in Belfast, were included in this study. One catheter was positioned in the right atrial appendage and another in the coronary sinus, to deliver a biphasic shock waveform. A voltage step-up protocol (50-300 V) was used for patient cardioversion. Residual atrial fibrillatory signal (RAFS) was derived from 60 seconds of surface ECG from defibrillator pads, prior to shock delivery, by bandpass filtering and ventricular activity (QRST) cancellation. QRST complexes were cancelled using a recursive least squared (RLS) adaptive filter. The maximal Lyapunov exponent (lambda), correlation dimension (course grained estimation, CDcg) and approximate entropy (ApEn) were extracted from the RAFS. These variables were calculated from 10 s of the RAFS before shock delivery. 26 patients were successfully cardioverted, employing a maximum energy of 11.84 joules. A lower lambda (0.037+/-0.006 vs. 0.044+/-0.008, P=0.01) and CDcg (5.552+/-2.075 vs. 6.592+/-1.130, P=0.049) were found in successfully cardioverted patients than in those non successful ones, with an energy <or=3 joules. Also, there was a significant positive correlation between the minimal defibrillation energy and lambda (r=0.483, P=0.013) in cardioverted patients. In conclusion, complexity analysis of the RAFS is useful for assessing the prospective efficacy of internal low energy cardioversion of patients with atrial fibrillation.

A clinical prediction rule for pulmonary tuberculosis in emergency departments

SETTING

University-affiliated hospital located in an area with a high incidence of pulmonary tuberculosis (PTB).

OBJECTIVE

To develop a clinical prediction rule (CPR) based on information obtainable on admission, to permit rapid identification of patients with PTB.

DESIGN

Information from patients with respiratory symptoms who attended the emergency department of Cayetano Heredia Hospital, Lima, Peru, was collected prospectively. Clinical symptoms, past medical history, demographic data and results of chest X-rays (CXRs), sputum smear and culture in Löwenstein-Jensen media were obtained. Based on logistic regression, we constructed a scoring system to predict PTB.

RESULTS

A total of 345 patients were enrolled in the study, including 109 (31%) culture-proven PTB cases. In logistic regression analysis, we found age, previous history of PTB, weight loss, presence of cavities, upper lobe infiltrate and miliary pattern on CXR as independent predictors of PTB. We designed a scoring system with these variables, taking into account their statistical weight. The score attained 93% sensitivity and 42% specificity.

CONCLUSION

The CPR that was developed performed well in our population. It merits further validation in other settings. It should not, however, replace, but should complement sputum microscopy when deciding on isolation, and it does not preclude microbiology in making a definitive diagnosis.