Plasmodium falciparum isolate with histidine-rich protein 2 gene deletion from Nyala City, Western Sudan.

In remote areas of malaria-endemic countries, rapid diagnostic tests (RDTs) have dramatically improved parasitological confirmation of suspected malaria cases, especially when skilled microscopists are not available. This study was designed to determine the frequency of Plasmodium falciparum isolates with histidine-rich protein 2 (pfhrp2) gene deletion as one of the possible factors contributing to the failure of PfHRP2-based RDTs in detecting malaria. A total of 300 blood samples were collected from several health centres in Nyala City, Western Sudan. The performance of PfHRP2-based RDTs in relation to microscopy was examined and the PCR-confirmed samples were investigated for the presence of pfhrp2 gene. A total of 113 out of 300 patients were P. falciparum positive by microscopy. Among them, 93.81% (106 out of 113) were positives by the PfHRP2 RDTs. Seven isolates were identified as false negative on the basis of the RDTs results. Only one isolate (0.9%; 1/113) potentially has pfhrp2 gene deletion. The sensitivity and specificity of PfHRP2-based RDTs were 93.81% and 100%, respectively. The results provide insights into the pfhrp2 gene deletion amongst P. falciparum population from Sudan. However, further studies with a large and systematic collection from different geographical settings across the country are needed.

CPHLN recommendations for the laboratory detection of Shiga toxin-producing Escherichia coli (O157 and non-O157).

Shiga toxin-producing Escherichia coli (STEC) are important enteric pathogens responsible for sporadic cases and outbreaks of gastroenteritis. E.coli O157:H7/NM (STEC O157) are the most commonly known STEC serotypes but it is now increasingly apparent that non-O157 STEC serotypes have been underreported in the past because they were not part of routine screening in many front-line laboratories. The Canadian Public Health Laboratory Network (CPHLN) has identified the need for improved detection and surveillance of non-O157 STEC and has developed the following recommendations to assist in the decision-making process for clinical and reference microbiology laboratories. These recommendations should be followed to the best of a laboratory's abilities based on the availability of technology and resources. The CPHLN recommends that when screening for the agents of bacterial gastroenteritis from a stool sample, front-line laboratories use either a chromogenic agar culture or a culture-independent diagnostic test (CIDT). CIDT options include nucleic acid amplification tests (NAATs) to detect Shiga toxin genes or enzyme immunoassays (EIAs) to detect Shiga toxins. If either CIDT method is positive for possible STEC, laboratories must have a mechanism to culture and isolate STEC in order to support both provincial and national surveillance as well as outbreak investigations and response. These CPHLN recommendations should result in improved detection of STEC in patients presenting with diarrhea, especially when due to the non-O157 serotypes. These measures should enhance the overall quality of healthcare and food safety, and provide better protection of the public via improved surveillance and outbreak detection and response.

Characteristics of e-cigarette users and their perceptions of the benefits, harms and risks of e-cigarette use: survey results from a convenience sample in Ottawa, Canada. / Caractéristiques des utilisateurs de cigarettes électroniques et leurs perceptions des avantages, des dangers et des risques de la cigarette électronique : résultats d'un sondage auprès d'un échantillon de commodité à Ottawa (Canada).

INTRODUCTION: Although e-cigarette use ("vaping") is increasing in Canada, few attempts have been made to describe e-cigarette users ("vapers"). In this context, we conducted a study in Ottawa, Canada, to describe e-cigarette users' perceptions of the benefits, harms and risks of e-cigarettes. We also collected information on why, how and where they use e-cigarettes as well as information on side effects. METHODS: A 24-item online survey was administered to individuals who purchased e-cigarettes or e-cigarette-related supplies at one of Ottawa's 17 e-cigarette shops. Descriptive analyses characterized respondents, and logistic regression models were fitted to evaluate the relationship between respondents' characteristics and their perception of e-cigarette harms. RESULTS: The mean age of the 242 respondents was 38.1 years (range: 16-70 years); 66% were male. Nearly all had smoked 100 or more cigarettes in their lifetime (97.9%). More than 80% indicated that quitting smoking was a very important reason for starting to use e-cigarettes and 60% indicated that they intend to stop using e-cigarettes at some point. About 40% reported experiencing some side effects within 2 hours of using e-cigarettes. Those who did not report experiencing any of the listed side effects had approximately 3.2 times higher odds of perceiving e-cigarettes as harmless than those who reported having side effects (odds ratio = 3.17; 95% confidence interval: 1.75-5.73). CONCLUSION: Our findings suggest that most e-cigarette users are using them to reduce or stop smoking cigarettes and perceive them as harmless. Due to our use of convenience sampling, the reader should be cautious in generalizing our findings to all Canadian e-cigarette users.

INTRODUCTION: Bien que l'utilisation de la cigarette électronique (« vapotage ¼) soit en hausse au Canada, peu d'efforts ont été consacrés à la description des utilisateurs de cigarettes électroniques (« vapoteurs ¼). C'est dans ce contexte que nous avons mené une étude à Ottawa (Canada) afin de décrire les perceptions qu'ont les utilisateurs de cigarettes électroniques des avantages, des dangers et des risques de ces dernières. Nous avons également recueilli de l'information pour savoir pourquoi, comment et où ils utilisent la cigarette électronique ainsi que sur les effets secondaires. MÉTHODOLOGIE: Un sondage en ligne de 24 questions a été soumis à des personnes ayant acheté des cigarettes électroniques ou des fournitures connexes dans l'un des 17 commerces de cigarettes électroniques à Ottawa. On a caractérisé les répondants au moyen d'analyses descriptives, puis nous avons appliqué des modèles de régression logistique pour évaluer la relation entre ces caractéristiques et la perception par les répondants des dangers de la cigarette électronique. RÉSULTATS: L'âge moyen des 242 répondants était de 38,1 ans (plage : 16 à 70 ans) et, de ce nombre, 66 % étaient des hommes. Près de la totalité (97,9 %) des répondants avaient fumé 100 cigarettes ou plus au cours de leur vie. Plus de 80 % des répondants ont indiqué que la volonté d'arrêter de fumer constituait l'une des principales raisons de recourir à la cigarette électronique, et 60 % ont mentionné qu'ils avaient l'intention de cesser l'utilisation de la cigarette électronique un jour. Environ 40 % des répondants ont fait état d'effets secondaires au cours des 2 heures suivant l'utilisation des cigarettes électroniques. Les répondants ayant signalé n'avoir ressenti aucun des effets secondaires énumérés étaient environ 3,2 fois plus nombreux à ne percevoir aucun danger dans la cigarette électronique que les personnes ayant signalé des effets secondaires (rapport de cotes = 3,17; intervalle de confiance à 95 % : 1,75 à 5,73). CONCLUSION: D'après nos constatations, la majorité des utilisateurs de cigarettes électroniques ont recours à ces dernières pour réduire ou cesser leur consommation de tabac et ils les perçoivent comme inoffensives. Étant donné que nous avons utilisé un échantillonnage de commodité, le lecteur doit faire preuve de prudence dans la généralisation de nos constatations à tous les utilisateurs de cigarettes électroniques au Canada.

New constraint on the existence of the µ+ → e+ γ decay.

The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay µ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.

A possible mechanism for Inv22-related F8 large deletions in severe hemophilia A patients with high responding factor VIII inhibitors.

BACKGROUND: Intron 22 inversion (Inv22) of the coagulation factor (F)VIII gene (F8) is a frequent cause of severe hemophilia A. In addition to Inv22, a variety of F8 mutations (1492 unique mutations) causing hemophilia A have been reported, of which 171 involve deletions of over 50 bp (HAMSTeRs database; http://hadb.org.uk/). However, only 10% of these large deletions have been fully characterized at the nucleotide level. PATIENTS AND METHODS: We investigated gene abnormalities in three unrelated severe hemophilia A patients with high titer FVIII inhibitors. They had previously been shown to carry large deletions of the F8, but the precise gene abnormalities remain to be elucidated. RESULTS: Inverse shifting-PCR (IS-PCR) Inv22 diagnostic tests revealed that these patients carried either type I or II Inv22. However, they showed a wild-type (WT) pattern in the IS-PCR Inv22 complementary tests. We further analyzed their X chromosomes to account for the puzzling results, and found that they had different centromeric breakpoints in the Inv22 X chromosomes, adjacent to the palindromic regions containing int22h-2 or -3, and their spacer region, respectively. The connections appeared to be shifted towards the telomere of the WT F8 Xq28, resulting in a new telomere with an additional intact int22h copy. CONCLUSIONS: These gene rearrangements might result from double-strand breaks in the most distal regions of the long arms of the Inv22 X chromosomes, followed by DNA restorations using the WT F8 Xq28 by non-homologous end joining or break-induced replication; thus leading to large F8 deletions in severe hemophilia A patients.

Note: wearable near-infrared spectroscopy imager for haired region.

A wearable optical topography system was developed that is based on near-infrared spectroscopy (NIRS) for observing brain activity noninvasively including in regions covered by hair. An avalanche photo diode, high voltage dc-dc converter, and preamplifier were placed in an electrically shielded case to be safely mounted on the head. Rubber teeth and a glass rod were prepared to clear away hair and reach the scalp. These devices realized for the first time a wearable NIRS imager for any region of the cortex. The activity in the motor cortex during finger tapping was successfully observed.

New limit on the lepton-flavor-violating decay µ+→e+γ.

We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay µ(+)e(+)γ. The likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10(14) muon decays, gives a 90% C.L. upper limit of 2.4×10(-12) on the branching ratio of the µ(+)→e(+)γ decay, constituting the most stringent limit on the existence of this decay to date.

Muscle and tendon properties during menstrual cycle.

The present study aimed to investigate the changes in the mechanical properties of human muscle and tendon during the menstrual cycle in vivo. The subjects were young healthy women (n=8, age 22.5+/-0.9 years) with a normal menstrual cycle. Cycle phases were divided into the menstrual (when estradiol and progesterone concentrations were low), ovulatory (when estradiol was elevated and progesterone was low), and luteal (when progesterone was elevated). Measurements included maximal isometric voluntary contraction (MVC), muscle activation level (using interpolated twitch method), and tendon properties (using ultrasonography) in knee extensors and plantar flexors. No significant changes in MVC and muscle activation level were found during the menstrual cycle. Similarly, there were no significant differences in the maximal elongation and stiffness of tendons among the three phases. These results suggested that the changes in female steroid hormones during the menstrual cycle did not affect the mechanical properties of human muscle and tendon.

Synthesis and spectroscopic studies of CoII, NiII, FeIII and ThIV complexes derived from 2,2'-dihydroxy-3,3'-di(carboxymethyl)-1,1'-binaphthyl.

The synthesis of 2,2'-dihydroxy-3,3'-di(carboxymethyl)-1,1'-binaphthyl (H2L) and its novel metal complexes with Co(II), Ni(II), Fe(III) and Th(IV) salts are reported. The ligand and its metal complexes have been characterized on the basis of analytical, conductance, spectral (IR, UV-vis, 1H NMR, mass) and magnetic susceptibility measurements. The Mössbauer spectrum of the Fe(III) complex indicates a low-spin octahedral geometry around the Fe(III) ion. The IR and 1H NMR spectral data show that the ligand behaves in a dibasic bidentate fashion coordinating to two metal atoms through the two deprotonated naphthyl OH groups and acts in a dibasic tetradentate manner using both carbonyl oxygen's and the deprotonated naphthyl OH groups coordinating to two metal ions. Thermal studies (TGA, DTA) confirm the presence of solvents either inside or outside the coordination sphere and support the mechanism of the decomposition process. The value of [alpha]D20 for the ligand has been determined in DMSO.

Characterization of the tryptophan residues of Escherechia coli alkaline phosphatase by phosphorescence and optically detected magnetic resonance spectroscopy.

The phosphorescence and zero field optically detected magnetic resonance (ODMR) of the tryptophan (Trp) residues of alkaline phosphatase from Escherechia coli are examined. Each Trp is resolved optically and identified with the aid of the W220Y mutant and the terbium complex of the apoenzyme. Trp(109), known from earlier work to be the source of room-temperature phosphorescence (RTP), emits a highly resolved low-temperature phosphorescence (LTP) spectrum and has the narrowest ODMR bands observed thus far from any protein site, revealing a uniquely homogeneous local environment. The decay kinetics of Trp(109) at 1.2 K reveals that the major triplet population (70%) undergoes inefficient crystallike spin-lattice relaxation by direct interaction with lattice phonons, the remainder being relaxed efficiently by local disorder modes. The latter population is smaller than is typical for protein sites, suggesting an unusual degree of local rigidity and order consistent with the long-lived RTP. Trp(220) emits a broader LTP spectrum originating to the blue of Trp(109). It has typically broad ODMR bands consistent with local heterogeneity. The LTP of Trp(268) has an ill-defined origin blue shifted relative to Trp(220) and ODMR frequencies consistent with a greater degree of solvent exposure. Trp(268) has noticeable dispersion of its decay kinetics, consistent with quenching at the triplet level by a nearby disulfide residue.

Wavelength dependence of the precision of noninvasive optical measurement of oxy-, deoxy-, and total-hemoglobin concentration.

The precision of noninvasive optical measurement of the concentration changes in oxy-, deoxy-, and total-hemoglobin depends on wavelength. For estimating the precision, we calculated the noise level of the concentration changes as the uncertainty in measurements using several wavelength pairs of light. Seven laser diodes (664-848 nm) were used simultaneously for spectroscopic measurement of brain activity during finger motor stimulation. We also used the analysis of error propagation from the uncertainty in direct measurements of absorbance changes to estimate indirectly the uncertainty of concentration changes. The measurement of the concentration changes made using an 830/664-nm pair are two times (oxy-Hb) and six times (deoxy-Hb) more precise than those made using an 830/782-nm pair.

Advanced gallbladder carcinoma with biliobiliary fistula, resected by hepatopancreatoduodenectomy, in an aged patient.

We report a 78-year-old man with a gallbladder carcinoma and biliobiliary fistula, diagnosed by percutaneous transhepatic cholangioscopic biopsy through the fistula. The impacted stones in the common hepatic duct were crushed, and then selective cholangiography under percutaneous transhepatic cholangioscopy (PTCS) revealed a biliobiliary fistula. Cholangioscopic biopsy tissues taken from the gallbladder revealed adenocarcinoma, but biopsies taken from the fistula revealed no evidence of malignancy. Further investigations indicated that the gallbladder carcinoma involved the duodenum and the distal common bile duct. A hepatopancreatoduodenectomy, including both an extended right hepatic lobectomy with resection of the caudate lobe and a pancreatoduodenectomy, was performed. Despite the patient's advanced age, he made an unremarkable postoperative recovery and was able to enjoy an active social life for 8 months after the surgery. We discuss biliobiliary fistula associated with gallbladder carcinomas and the use of hepatopancreatoduodenectomy for advanced biliary cancer in aged patients.

Activation of visual cortex in REM sleep measured by 24-channel NIRS imaging.

To visualize dreaming brain functions we studied hemodynamic changes in the visual cortex during the transition from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep, using a 24-channel Near-Infrared Spectroscopy (NIRS) imaging method. Results were compared to the activation in visual cortex by visual stimulation during wakefulness. Subjects were four healthy males between 25 and 49 years of age. Five all-night polysomnographic and NIRS recordings were made. Increases in the oxygenated hemoglobin concentration in visual cortex were observed from nine of 14 REM periods. The activated areas were broader during REM sleep than during visual stimulation. These findings suggest that activation of visual cortex in REM sleep might represent dream-related brain activity.

High-Temperature Infrared Emission Measurements on HNC.

The emission spectrum of HNC has been measured from 400 to 4100 cm(-1). The HNC was observed as an equilibrium mixture of HCN and HNC in a fused quartz cell heated to 1370 K. The three fundamental bands and many hot bands of HNC were measured with resolutions ranging from 0.006 cm(-1) for the lowest fundamental to 0.033 cm(-1) for the other two. High rotational levels up to J=62 were observed as well as vibrational levels up to v(2)=5. Now all the quadratic contributions to the vibrational and rotational term values have been determined, as well as some higher order terms. Copyright 2001 Academic Press.

Determination of relative triplet sublevel populating rates during optical pumping using ODMR.

A method is introduced, based on optical detection of triplet state magnetic resonance (ODMR), to determine the relative populating rates of photoexcited triplet state sublevels during optical pumping. Phosphorescence transients induced by microwave rapid passage during optical pumping are analyzed globally utilizing kinetic parameters obtained from separate microwave-induced delayed phosphorescence measurements to obtain relative sublevel populating rates. Results are unaffected by phosphorescence from triplet populations that do not yield an ODMR response. The method is applied to the triplet state of the indole chromophore in various environments to reveal the effects of local interactions on the pattern of intersystem crossing. Enhanced spin--orbit coupling effects are attributed to interactions that reduce the planar symmetry of the indole chromophore.

Phosphorescence and optically detected magnetic resonance of HIV-1 nucleocapsid protein complexes with stem-loop sequences of the genomic Psi-recognition element.

The binding of NCp7, the nucleocapsid protein of human immunodeficiency virus type 1, to oligonucleotide stem--loop (SL) sequences of the genomic Psi-recognition element has been studied using fluorescence, phosphorescence, and optically detected magnetic resonance (ODMR). RNA SL2, SL3, and SL4 constructs bind with higher affinity than the corresponding DNAs. G to I substitutions in the SL3 DNA loop sequence lead to reduced binding affinity and significant changes in the triplet state properties of Trp37 of NCp7, implicating these bases in contacts with aromatic amino acid residues of the zinc finger domains of NCp7, in agreement with the NMR structure of the 1:1 complex of NCp7 and SL3 RNA [DeGuzman, R. N., Wu, Z. R., Stalling, C. C., Pappaladro, L., Borer, P. N., and Summers, M. F. (1998) Science 279, 384-388]. The NCp7 to SL binding stoichiometry is 2:1 for intact SL sequences but is reduced to 1:1 for SL variants with an abasic or hydrocarbon loop. It is proposed that Delta D/Delta E(0,0), where Delta D is the change in the zero-field splitting D parameter and Delta E(0,0) is the shift of the tryptophan phosphorescence origin, provides a measure of aromatic stacking interactions with nucleic acid bases. Values on the order of 10(-5) indicate significant stacking interactions, while values closer to 10(-6) result from interactions not involving aromatic stacking. Binding of NCp7 to oligonucleotide substrates produces shortened Trp37 triplet state lifetimes by enhancement of k(x) and an increase of the relative value of P(x), the intersystem crossing rate to the T(x) sublevel. These effects are attributed to a reduction in the degree of electronic symmetry of Trp37 in the complexes. Guanine and adenine triplet states produced by optical pumping of SL3 DNA are characterized. We find, as with tryptophan, that D < 3E.

Acute effects of cigarette smoking on platelet-dependent thrombin generation.

AIMS: Thrombin is an important factor in the pathogenesis of thrombotic diseases. To clarify whether smoking has an effect in platelet-dependent thrombogenesis, we studied the acute effects of smoking on platelet-dependent thrombin level in smokers. METHODS AND RESULTS: Subjects consisted of ten smokers and nine non-smokers. Platelet-dependent thrombin level measured after overnight fasting was greater in smokers than in non-smokers (smokers vs non-smokers, 121 +/- 47 vs 56 +/- 5 mIU. ml(-1), P < 0.01). When subjects in the smokers group smoked two cigarettes containing 0.9 mg of nicotine per cigarette, platelet-dependent thrombin levels showed a transient three-fold increase in blood samples obtained immediately after smoking (365+/-76 mIU. ml(-1), P < 0.001). Thrombin levels in the blood samples obtained 10 min and 30 min after smoking were less than that in the samples obtained immediately after smoking ceased, but were not significantly different from those in the samples obtained before smoking. Blood nicotine level increased significantly immediately after smoking (P < 0.001), and plasma protein C activity decreased significantly 30 min after smoking (P < 0.05). When nicotine or cotinine was added to the platelet-rich plasma of non-smokers ex vivo, the platelet-dependent thrombin level increased significantly (P < 0.002). CONCLUSION: Platelet-dependent thrombin level is enhanced in smokers, even when not smoking, when compared with non-smokers and increases immediately after smoking. Increases in nicotine and cotinine levels caused by smoking induced a prothrombotic state in smokers via increased platelet-dependent thrombogenesis.

[Noninvasive higher-order brain-function imaging by near-infrared spectroscopy].

The simultaneous position encoding method for optical topography was developed. Each channel has dual-wavelength optics to separately determine the changes in oxy-hemoglobin and deoxy-hemoglobin concentrations around their isobestic points at 805 nm. Part of the incident light penetrates the scalp and skull and is reflected from brain tissues including the cerebral cortex. Any change in the light extinction is mainly due to changes in the oxy-hemoglobin and/or the deoxy-hemoglobin concentration during the activation of a functional area linked to a neuronal activity. Unlike conventional functional imaging methodologies, it can be used for behavioral studies because the flexible optical fibers allow a subject to move, and a very light and compact system can be made. Noninvasive dynamic optical topography has a wide variety of applications from basic science to clinical medicine. Several applications, such as the study of the Broca and Wernicke language areas, the assessment of the dominant hemisphere of the brain, epilepsy focus determination, and sleep studies are reported. We also tested a 14-month-old baby with a extremely abnormal brain.

Platelet-dependent thrombin generation in patients with unstable angina pectoris.

Platelet-dependent thrombin generation was assessed during both unstable and stable periods in 59 patients with unstable angina and at rest in 31 healthy controls. Thrombin generation during the unstable period was significantly greater than that at rest in the healthy control group (p < 0.0001) and that during the stable period (p < 0.0001). Changes in thrombin generation were related to the time after onset of unstable angina, not to degree of improvement in the severity of coronary stenosis.

Effect of nucleic acid binding on the triplet state properties of tetrapeptides containing tryptophan and 6-methyltryptophan: a study by phosphorescence and ODMR spectroscopy.

Complexes of four peptides [KWGK, KGWK, K(6MeW)GK, KG(6MeW)K] with the nucleic acids [poly(A), poly(C), poly(U), poly(I), and rG(8)] have been investigated by phosphorescence and optically detected magnetic resonance (ODMR) spectroscopy. The intrinsic spectroscopic probes used in these studies are tryptophan (W) and 6-methyltryptophan (6MeW). Binding to the nucleic acids results in a red-shift of the phosphorescence 0,0-band (delta E(0,0)) of the aromatic residue as well as a reduction of its zero-field splitting parameter (delta D). Results are compared with earlier studies of the HIV-1 nucleocapsid protein, NCp7, that contains a single tryptophan residue (Trp37) within a retroviral zinc finger sequence. Binding of poly(A) or poly(U) to the tetrapeptides induces larger delta E(0,0) and delta D than when bound to NCp7, indicating stronger stacking interactions. Poly(I), on the other hand, produces larger shifts in Trp37 of NCp7. Binding of rG(8) produces sequence-dependent effects in the peptides. When bound to NCp7, but in contrast with tetrapeptide binding, nucleic acids produce large changes in triplet state kinetics consistent with enhanced spin-orbit coupling. These results are discussed in terms of three limiting types of tryptophan-base interaction: intercalation, aromatic stacking, and edge-on interaction. These should have differing effects on the properties of the triplet state.