Tuberculin skin testing and QuantiFERON™-TB Gold Plus positivity among household contacts in Vietnam.

SETTING: TB infection (TBI) is diagnosed using the technique-dependent tuberculin skin test (TST) or costly, more accurate interferon-gamma release assays. The TST (⩾10 mm) threshold was indicated by previous research among household contacts in Vietnam, but routine implementation with a different tuberculin reagent showed unexpectedly low TST positivity. OBJECTIVE: TST (⩾5 mm and ⩾10 mm) results were compared to QuantiFERON™-TB Gold Plus (QFT) results in household contacts during community campaigns in 2020 and 2021. DESIGN: This was a cross-sectional multi-center implementation study. RESULTS: Among 1,330 household contacts in 2020, we found a TBI prevalence of 38.6% (QFT), similar to TST ⩾5 mm (37.4%) and higher than TST ⩾10 mm (13.1%). QFT+/TST+ was higher for TST ⩾5 mm (20.7%) than TST ⩾10 mm (9.4%). QFT was not discordant with TST ⩾5 mm (McNemar's test = 0.6, P = 0.5) but was discordant with TST ⩾10 mm (McNemar's test = 263.9, P < 0.01). Older age and Southern region increased odds for positive TST ⩾5 mm and QFT with weaker associations for TST ⩾10 mm. Agreement and discordance were similar in 2021 for 1,158 household contacts. CONCLUSION: Tuberculin reagents affect TST positivity rates. High TB burden countries should monitor reliability of TBI diagnosis, including tuberculin potency, cold chain, and TST technique to optimize eligibility for TB preventive treatment.

CONTEXTE: L'infection tuberculeuse (TBI) est diagnostiquée à l'aide du test cutané à la tuberculine (TST), qui dépend de la technique, ou de tests de libération de l'interféron-gamma, coûteux et plus précis. Des recherches antérieures ont indiqué que le TST (⩾10 mm) est généralement utilisé pour diagnostiquer la TB parmi les contacts familiaux au Vietnam ; la mise en œuvre de routine avec un réactif de tuberculine différent a montré une faible positivité inattendue du TST. OBJECTIF: Les résultats du TST (⩾5 mm et ⩾10 mm) ont été comparés aux résultats de QuantiFERON™-TB Gold Plus (QFT) chez les contacts familiaux au cours des campagnes communautaires de 2020 et 2021. MÉTHODE: Il s'agissait d'une étude transversale multicentrique de mise en œuvre. RÉSULTATS: Parmi 1 330 contacts familiaux en 2020, nous avons trouvé une prévalence de TBI de 38,6% (QFT), similaire au TST ⩾5 mm (37,4%) et plus élevée que le TST ⩾10 mm (13,1%). Le QFT+/TST+ était plus élevé pour le TST ⩾5 mm (20,7%) que pour le TST ⩾10 mm (9,4%). Le QFT n'était pas discordant avec le TST ≥5 mm (test de McNemar = 0,6 ; P = 0,5) mais était discordant avec le TST ⩾10 mm (test de McNemar = 263,9 ; P < 0,01). L'âge avancé et la région méridionale augmentaient les probabilités d'un TST positif ⩾5 mm et d'un QFT, avec des associations plus faibles pour un TST ⩾10 mm. La concordance et la discordance étaient similaires en 2021 pour 1 158 contacts familiaux. CONCLUSION: Les réactifs de tuberculine affectent les taux de positivité des TST. Les pays à forte charge de TB doivent surveiller la fiabilité du diagnostic de TBI, y compris la puissance de la tuberculine, la chaîne du froid et la technique du TST afin d'optimiser l'éligibilité au traitement préventif de la TB.

Diagnostic value of cerebral vasospasm by transcranial doppler ultrasound in Vietnamese patients with subarachnoid hemorrhage.

OBJECTIVE: Although the application of transcranial Doppler (TCD) ultrasonography in clinical diagnosis of cerebral vasospasm is popular in clinical practice in Vietnam, available evidence of the predictive value of vasospasm on TCD in the literature was mostly reported from large institutions in developed countries. Hence, this study was conducted to evaluate the value of TCD ultrasonography in the diagnosis of vasospasm in patients with subarachnoid hemorrhage (SAH) in Vietnam. PATIENTS AND METHODS: This is a prospective observational study of all aneurysmal SAH patients consecutively admitted to a single center between 2008 and December 2011. TCD and 64-slice computed tomographic angiography (CTA) were used to cerebral vasospasm in SAH patients. RESULTS: 316 patients were analyzed (mean age = 52.97±12.27 years, 52.2% males). There were statistically significant difference rates of the cerebral vasospasm by Hunt and Hess Classification and Fisher classification (p <0.01). The proportion of the patients with cerebral vasospasm who were diagnosed exactly by TCD was 95.2%, while the proportion of the patients without cerebral vasospasm diagnosed exactly was 91.5%. TCD predictive diagnostic value was the highest, with the sensitivity of 0.95 (95% CI: 0.91-0.98), specificity of 0.91 (95% CI: 0.85-0.96), positive predictive value of 0.94 (5% CI: 0.90-0.97) and negative predictive value of 0.93 (95 CI: 0.87-0.97). Hemiplegia was the clinical symptom with the highest diagnostic value with the sensitivity of 0.34 (95% CI: 0.27-0.41), specificity of 0.92 (95% CI: 0.86-0.96), positive predictive value of 0.86 (95% CI: 0.76-0.93) and negative predictive value of 0.49 (95% CI: 0.41-0.54). CONCLUSIONS: Evidence of vasospasm diagnosis on TCD ultrasonography was found with high accuracy. Current study enables to suggest the wide application of TCD in Vietnam health facilities from central to grassroots levels instead of the CTA use.

A multiple-locus variable-number tandem repeat analysis (MLVA) of Listeria monocytogenes isolated from Norwegian salmon-processing factories and from listeriosis patients.

The objective of this study was to characterize Listeria monocytogenes isolated from farmed Atlantic salmon (Salmo salar) and the processing environment in three different Norwegian factories, and compare these to clinical isolates by multiple-locus variable-number tandem repeat analysis (MLVA). The 65 L. monocytogenes isolates obtained gave 15 distinct MLVA profiles. There was great heterogeneity in the distribution of MLVA profiles in factories and within each factory. Nine of the 15 MLVA profiles found in the fish-associated isolates were found to match human profiles. The MLVA profile 07-07-09-10-06 was the most common strain in Norwegian listeriosis patients. L. monocytogenes with this profile has previously been associated with at least two known listeriosis outbreaks in Norway, neither determined to be due to fish consumption. However, since this profile was also found in fish and in the processing environment, fish should be considered as a possible food vehicle during sporadic cases and outbreaks of listeriosis.

Effects of short-course oral corticosteroid therapy in early dengue infection in Vietnamese patients: a randomized, placebo-controlled trial.

BACKGROUND: Patients with dengue can experience a variety of serious complications including hypovolemic shock, thrombocytopenia, and bleeding. These problems occur as plasma viremia is resolving and are thought to be immunologically mediated. Early corticosteroid therapy may prevent the development of such complications but could also prolong viral clearance. METHODS: We performed a randomized, placebo-controlled, blinded trial of low-dose (0.5 mg/kg) or high-dose (2 mg/kg) oral prednisolone therapy for 3 days in Vietnamese patients aged 5-20 years admitted with dengue and fever for ≤72 hours, aiming to assess potential harms from steroid use during the viremic phase. Intention-to-treat analysis was performed using linear trend tests with a range of clinical and virological endpoints specified in advance. In addition to recognized complications of dengue, we focused on the are under the curve for serial plasma viremia measurements and the number of days after enrollment to negative viremia and dengue nonstructural protein 1 status. RESULTS: Between August 2009 and January 2011, 225 participants were randomized to 1 of the 3 treatment arms. Baseline characteristics were similar across the groups. All patients recovered fully and adverse events were infrequent. Aside from a trend toward hyperglycemia in the steroid recipients, we found no association between treatment allocation and any of the predefined clinical, hematological, or virological endpoints. CONCLUSIONS: Use of oral prednisolone during the early acute phase of dengue infection was not associated with prolongation of viremia or other adverse effects. Although not powered to assess efficacy, we found no reduction in the development of shock or other recognized complications of dengue virus infection in this study.

Scattered radiation emission imaging: principles and applications.

Imaging processes built on the Compton scattering effect have been under continuing investigation since it was first suggested in the 50s. However, despite many innovative contributions, there are still formidable theoretical and technical challenges to overcome. In this paper, we review the state-of-the-art principles of the so-called scattered radiation emission imaging. Basically, it consists of using the cleverly collected scattered radiation from a radiating object to reconstruct its inner structure. Image formation is based on the mathematical concept of compounded conical projection. It entails a Radon transform defined on circular cone surfaces in order to express the scattered radiation flux density on a detecting pixel. We discuss in particular invertible cases of such conical Radon transforms which form a mathematical basis for image reconstruction methods. Numerical simulations performed in two and three space dimensions speak in favor of the viability of this imaging principle and its potential applications in various fields.

Alert management for home healthcare based on home automation analysis.

Rising healthcare for elder and disabled people can be controlled by offering people autonomy at home by means of information technology. In this paper, we present an original and sensorless alert management solution which performs multimedia and home automation service discrimination and extracts highly regular home activities as sensors for alert management. The results of simulation data, based on real context, allow us to evaluate our approach before application to real data.

Compton scattered imaging based on the V-line radon transform and its medical imaging applications.

The Radon transform (RT) on straight lines deals as mathematical foundation for many tomographic modalities (e.g. Xray scanner, Positron Emission Tomography), using only primary radiation. In this paper, we consider a new RT defined on a pair of half-lines forming a letter V, arising from the modeling a two-dimensional emission imaging process by Compton scattered gamma rays. We establish its analytic inverse, which is shown to support the feasibility of the reconstruction of a two-dimensional image from scattered radiation collected on a one-dimensional collimated camera. Moreover, a filtered back-projection inversion method is also constructed. Its main advantages are algorithmic efficiency and computational rapidity. We present numerical simulations to illustrate the working. To sum up, the V-line RT leads not only to a new imaging principle, but also to a new concept of detector with high energetic resolution capable to collect the scattered radiation.

On the v-line radon transform and its imaging applications.

Radon transforms defined on smooth curves are well known and extensively studied in the literature. In this paper, we consider a Radon transform defined on a discontinuous curve formed by a pair of half-lines forming the vertical letter V. If the classical two-dimensional Radon transform has served as a work horse for tomographic transmission and/or emission imaging, we show that this V-line Radon transform is the backbone of scattered radiation imaging in two dimensions. We establish its analytic inverse formula as well as a corresponding filtered back projection reconstruction procedure. These theoretical results allow the reconstruction of two-dimensional images from Compton scattered radiation collected on a one-dimensional collimated camera. We illustrate the working principles of this imaging modality by presenting numerical simulation results.

Nanopost plasmonic crystals.

We describe a class of plasmonic crystal that consists of square arrays of nanoposts formed by soft nanoimprint lithography. As sensors, these structure show somewhat higher bulk refractive index sensitivity for aqueous solutions in the visible wavelength range as compared to plasmonic crystals consisting of square arrays of nanowells with similar dimensions, with opposite trends for the case of surface bound layers in air. Three-dimensional finite-difference time-domain simulations quantitatively capture the key features and assist in the interpretation of these and related results.

Stark effect of interactive electron-hole pairs in spherical semiconductor quantum dots.

We present a theoretical approach, based on the effective mass approximation model, on the quantum-confinement Stark effects for spherical semiconducting quantum dots in the regime of strong confinement of interactive electron-hole pairs and limiting weak electric field. The respective roles of Coulomb potential and polarization energy are investigated in detail. Under reasonable physical assumptions, analytical calculations can be performed. They show that the Stark shift is a quadratic function of the electric field amplitude in this regime. The computed numerical values obtained from this approach are found to be in good agreement with experimental data over a significant domain of quantum dot sizes.

On high sensitivity emission imaging by scattered gamma radiation.

A new concept of gamma emission imaging based on the use of scattered radiation with a non collimated gamma camera is put forward. A few years ago, scattered radiation by Compton effect is shown to be capable to reconstruct a three dimensional object using a standard collimated gamma camera. To increase drastically in sensitivity, we propose now that data acquisition should be performed without collimation. We present this new image formation by scattered radiation via the properties of its Point Spread Functions (PSF). Comparison with the PSF in the presence of a collimator exhibits a striking image enhancement. We also present numerical simulations on image formation and reconstruction to support the attractiveness of this modality.

Novel approach to stationary transmission scanning using Compton scattered radiation.

Transmission scanning-based estimation of the attenuation map plays a crucial role in quantitative radionuclide imaging. X-ray computed tomography (CT) reconstructs directly the attenuation coefficients map from data transmitted through the object. This paper proposes an alternative route for reconstructing the object attenuation map by exploiting Compton scatter of transmitted radiation from an externally placed radionuclide source. In contrast to conventional procedures, data acquisition is realized as a series of images parameterized by the Compton scattering angle and registered on a stationary gamma camera operating without spatial displacement. Numerical simulation results using realistic voxel-based phantoms are presented to illustrate the efficiency of this new transmission scanning approach for attenuation map reconstruction. The encouraging results presented in this paper may suggest the possibility of proposing a new concept for emission/transmission imaging using scattered radiation, which has many advantages compared to conventional technologies.

The Mathematical Foundations of 3D Compton Scatter Emission Imaging.

The mathematical principles of tomographic imaging using detected (unscattered) X- or gamma-rays are based on the two-dimensional Radon transform and many of its variants. In this paper, we show that two new generalizations, called conical Radon transforms, are related to three-dimensional imaging processes based on detected Compton scattered radiation. The first class of conical Radon transform has been introduced recently to support imaging principles of collimated detector systems. The second class is new and is closely related to the Compton camera imaging principles and invertible under special conditions. As they are poised to play a major role in future designs of biomedical imaging systems, we present an account of their most important properties which may be relevant for active researchers in the field.

Construction and evaluation of a humic acid column: implication for pesticide risk assessment.

In this paper, humic acid (HA), known to play a large role in the binding and transport of pesticides in soil, was immobilized on a chromatographic support. Then, the association of some herbicides and rodenticides with the main soil component HA was examined using this novel chromatographic column. It appeared that HA has a lower affinity for neutral than for charged pesticides. Moreover, the influence of various parameters was investigated on the pesticide retention in order to providevaluable information about both the binding mechanism and the utilization conditions of the HA column. For all the pesticides studied, a change was clearly vizualized in the HA-pesticide association mechanism at a critical value of the Na+ concentration in the bulk solvent, x(c), equal to 0.6 M. Around this value, the HA structure balanced between a flexible linear conformation for x < x(c) and a random coil form for x > x(c). This work confirmed the conformation change on HA immobilized on silica. As well, only for the charged pesticides, it was clearly pointed out that below a Na+ concentration equal to 0.3 M, the pesticide binding to HA decreased when the salt concentration was enhanced due to an ion pair formation and a competition effect between the sodium cation and pesticide to bind to the HA molecule. Furthermore, it was established that the HA column was stable during an extended period of time, indicating that the HA column could soon become very attractive to determine the risk assessment of pesticides.

Plant-originated glycoprotein, G-120, inhibits the growth of MCF-7 cells and induces their apoptosis.

We characterized the biological function of G-120, glycoprotein isolated from the ethanol extract of the herb, Ulmus davidiana Nakai (UDN). G-120 has anti-tumor activity and significantly inhibited proliferation of MCF-7 cells, as measured by the thymidine uptake assay. In addition, MTT and trypan blue exclusion experiments showed that the G-120-mediated inhibition of DNA synthesis may be due to a cytostatic, rather than a cytotoxic effect. Further studies of DNA analysis and propidium iodide staining revealed that G-120 induces apoptosis in MCF-7 cells. Interestingly, G-120 (100 microg/ml) completely suppressed the binding of NF-kappaB to DNA and increased the cytosolic level of IkappaBalpha which prevented nuclear translocation of NF-kappaB. In addition, G-120 increased the expression of c-Jun, Fra-1, and Fra-2, but did not affect the expression of c-Fos. Collectively, it is believed that G-120 exerts an important role in the induction of apoptosis, suppression of NF-kappaB activation, and induction of c-Jun/Fra-1 or c-Jun/Fra-2 dimerization in MCF-7 cells. Consequently, G-120 could be considered as an anti-cancer agent, although further detailed experiments should be performed.

Analysis of the progesterone displacement of its human serum albumin binding site by beta-estradiol using biochromatographic approaches: effect of two salt modifiers.

The mechanisms of (i) the binding of two sex-hormones (i.e. progesterone and beta-estradiol) to human serum albumin (HSA) and (ii) the progesterone displacement of its HSA binding cavity by beta-estradiol were studied by biochromatography using three different methods. In the first time, zonal elution method was used to prove the direct competition effect between the two sex-hormone. In the second time, the competition effect between beta-estradiol and progesterone to bound on the same HSA site was analysed by the competitive bi-Langmuir approach. Finally, the thermodynamic data of these two binding processes were studied. The Gibbs free energy value (Delta(approximately)G degrees) of the displacement equilibrium was negative demonstrating that beta-estradiol displaced progesterone of its HSA binding cavity. Moreover, the effect of two chloride modifiers (i.e. Na(+), Mg(2+)) on these two binding processes were analysed. Results showed that in the salt biological concentration ranges, the Mg(2+) cation enhanced strongly the bioavailable progesterone, whereas the Na(+) cation interacted slowly on the progesterone displacement of its HSA binding site by beta-estradiol. This study showed that it must be useful to carry out more in vivo test on the magnesium supplementation effect for women who suffer from estrogen dominance syndrome.

A chromatographic approach to analyze dansyl amino acid-HP-beta-CD association using macrocyclic antibiotic as the stationary phase.

The retention mechanism for a series of D,L-dansyl amino acids in high-performance liquid chromatography is investigated using a teicoplanin stationary phase and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as the mobile phase additive (0-16mM). A theoretical treatment is developed to determine the HP-beta-CD influence on the equilibrium between the teicoplanin phase and the aqueous medium, respectively. From the experimental data, the association constants of the D,L-dansyl amino acids-HP-beta-CD inclusion complexes are determined and discussed in relation to the enantiomer structure. A thermodynamic study confirms that both the retention and complexation mechanisms are independent of the dansyl amino acid molecular structure and its absolute carbon configuration.

Analytical study of comprehensive and targeted multidimensional gas chromatography incorporating modulated cryogenic trapping.

This paper reports the results of an analytical study comparing capillary gas chromatography (GC) operated in the normal mode with 2 new GC techniques, comprehensive GC (GC x GC) and targeted (or selective) multidimensional GC, which use a longitudinally modulated cryogenic system (LMCS), recently developed in our laboratory. A high-temperature application of derivatized sterols, of interest in fecal pollution monitoring, was chosen for this work. A directly connected coupled-column ensemble was used, comprising a nonpolar column and a moderately polar column. With LMCS, effluent from the first column is zone-compressed in a cryogenic trap and then pulsed to a short second column, producing narrower peaks with sharp, tall peak responses at the detector. The modulator is operated at a constant frequency, e.g., 0.25 s(-1), to produce the GC x GC result, or is moved in a predefined manner so that whole peaks are selectively trapped and subsequently pulsed through to the second column in the targeted mode. Standard solutions containing a mixture of 7 sterols and 5-alpha-cholestane internal standard were used. Detection sensitivity is increased by a factor of >25 with the use of LMCS. The estimated limit of detection was about 0.1 microg/mL when normal GC with flame ionization detection (GC/FID) and a 1.0 microL splitless injection volume were used, compared with 0.02 and 0.004 microg/mL for the LMCS operated in GC x GC and selective modes, respectively. Calibration curves for GC/FID were linear over the 0.1-2.0 microg/mL range tested. Reproducibilities for the GC x GC and normal GC modes were comparable; generally, relative standard deviations (RSD) were on the order of 3-4%, based on raw peak responses. Improved reproducibility was found for selective LMCS operation, at an RSD of around 2%; with internal standardization, better results were achieved. The coupled-column arrangement allowed complete separation of sterol peaks from overlapping impurity peaks in a number of instances with LMCS modes, and its use should improve data quality over that of normal GC operation, in which the overlapping peaks interfere with measurement of peak response in the normal mode.

High-performance thin-layer chromatographic determination of 5-methoxypsoralen in serum from patients.

A simple and rapid high-performance thin-layer chromatographic (HPTLC) determination of 5-methoxypsoralen in serum is necessary for the therapeutic survey of patients treated with Puvatherapy (psoralen+UVA). The assay for this biological fluid involves an extraction with heptane-dichloromethane (4:1, v/v). The analytical method is linear from 50 to 250 ng/ml. This assay range is adequate for analysing human serum, as it corresponds to psoralen concentrations measured in serum from patients treated with psoralen and UVA against psoriasis and vitiligo. The limit of detection is 15 ng/ml. The coefficient of variation was less than 7%.

Do direct current electric fields enhance micturition in the spinal cat?

Changes in micturition behavior and motoneuron ultrastructure were studied in spinal cats to determine the effects of direct current (DC) electric field treatment. Adult cats received a complete injury at T8. A treatment group with an implanted 15 microA DC source and electrodes positioned near the lesion site was compared with non-treatment groups that were either operated or unoperated. Both bladder emptying with Crede and the withdrawal reflex were improved in the treatment group compared with the non-treatment group. Urodynamic procedures showed that high urethral resistance and pelvic floor activity following spinal injury was partially reduced in the stimulated cat, indicating inhibition of the urethral sphincter. The ultrastructural analysis of Onuf's nucleus suggested a similar synaptic input in all three groups. In conclusion, possible activation of inhibitory processes and/or neural plasticity best explain the early improvement of bladder function seen following electrical stimulation.