Diagnostic role of internal mammary lymph node involvement in tuberculous pleurisy: a multicenter study

BACKGROUND AND OBJECTIVES

Diagnosis of tuberculous pleurisy (TP) may be challenging and it often requires pleural biopsy. A tool able to increase pre-test probability of TP may be helpful to guide diagnostic work-up and enlargement of internal mammary lymph node (IMLN) has been suggested to play a potential role. The aim of the present investigation was to assess role of IMLN involvement in TP in a multi-centric case-control study, by comparing its prevalence and test performance to those observed in patients with infectious, non-tuberculous pleurisy (NTIP), and in controls free from respiratory diseases (CP).

METHODS

A total of 419 patients, from 14 Pulmonology Units across Italy were enrolled (127 patients affected by TP, 163 affected by NTIP and 129 CP). Prevalence, accuracy and predictive values of ipsilateral IMLN involvement between cases and control groups were assessed, as well as concordance between chest computed tomography (CT scan) and thoracic ultrasound (TUS) measurements.

RESULTS

The prevalence of ipsilateral IMLN involvement in TP was significantly higher than that observed in NTIP and CP groups (respectively 77.2%, 39.3% and 14.7%). Results on test performance, stratified by age, revealed a high positive predictive value in patients aged ≤50 years, while a high negative predictive value in patients aged >50 years. The comparison between CT scan and ultrasound showed moderate agreement (Kappa=0.502).

CONCLUSIONS

Evaluation of IMLN involvement plays a relevant role in assessing the pre-test probability of TP. Considering the increasing global prevalence of mycobacterial infections, a tool able to guide diagnostic work-up of suspected TP is crucial, especially where local sources are limited.

Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule

Despite theoretical evidence that the model commonly referred to as the 3500-kcal rule grossly overestimates actual weight loss, widespread application of the 3500-kcal formula continues to appear in textbooks, on respected government- and health-related websites, and scientific research publications. Here we demonstrate the risk of applying the 3500-kcal rule even as a convenient estimate by comparing predicted against actual weight loss in seven weight loss experiments conducted in confinement under total supervision or objectively measured energy intake. We offer three newly developed, downloadable applications housed in Microsoft Excel and Java, which simulates a rigorously validated, dynamic model of weight change. The first two tools available at http://www.pbrc.edu/sswcp, provide a convenient alternative method for providing patients with projected weight loss/gain estimates in response to changes in dietary intake. The second tool, which can be downloaded from the URL http://www.pbrc.edu/mswcp, projects estimated weight loss simultaneously for multiple subjects. This tool was developed to inform weight change experimental design and analysis. While complex dynamic models may not be directly tractable, the newly developed tools offer the opportunity to deliver dynamic model predictions as a convenient and significantly more accurate alternative to the 3500-kcal rule.

Recombination dynamics of deep defect states in zinc oxide nanowires

The recombination dynamics of defect states in zinc oxide nanowires has been studied by developing a general expression for time-resolved photoluminescence intensity based on a second-order approximation for the radiative and non-radiative recombination rates. The model allows us to determine the parameters that characterize the recombination from deep defect states (defect concentration, unimolecular lifetime and bimolecular coefficient) through multi-fitting analysis of time-resolved photoluminescence measurements. Analyses conducted on zinc oxide nanowires gave deep state concentrations of the order of 10(18) cm(-3) and unimolecular lifetimes and bimolecular recombination coefficient comparable to those typical of interband recombination in direct gap semiconductors. The consistency of a 'two-channel decay' model (double exponential decay) has been tested by means of a similar analysis procedure. The results suggest that double exponential fitting of time-resolved photoluminescence data of zinc oxide nanowires may be just a mere phenomenological tool which does not reflect the real recombination dynamics of the visible emission band.

Ion specific effects on phase transitions in protein solutions

A recent Monte Carlo simulation determined the potential of mean force between two lysozyme molecules in various aqueous solutions [M. Lund, Phys. Rev. Lett. 100, 258105 (2008)]. The study involved a combination of explicit solvent and continuum model simulations and showed that there are significant ion-specific protein-protein interactions due to hydrophobic patches on the protein surfaces. In this paper we use the results of their study to determine the phase diagram for lysozyme for aqueous solutions of NaCl and NaI. Two of the three phase diagrams have a stable fluid-fluid critical point, while the third has a slightly metastable critical point. This results from a secondary extremum in the potential associated with a repulsive interaction. This repulsive interaction reduces the effective range of the attractive interaction and produces a metastable critical point. We compare the results of one of these phase diagrams with that for a model that includes ion-dispersion forces, but does not contain solvent structural effects.

Hofmeister effect and the phase diagram of lysozyme

The phase diagrams for lysozyme are calculated for two different precipitant salts, NaCl and NaSCN, using a potential of mean force that takes into account contributions from ion-dispersion forces [M. Boström, J. Phys. Chem. B 110, 24757 (2006)]. Our results are consistent with a recent perturbation theory calculation (referenced above) in that the phase diagram for lysozyme with NaCl is quite different than for lysozyme with NaSCN for the same molar concentration (0.2M) . However, in contrast to the perturbation theory calculation, we find that the lysozyme phase diagram with NaCl has a metastable fluid-fluid coexistence curve and that the metastability gap in the case of NaSCN is much larger than predicted by perturbation theory.

Field localization and enhanced Second-Harmonic Generation in silicon-based microcavities

High-quality amorphous Silicon Nitride (a-Si(1-x)N(x):H) Fabry-Pérot microcavities can show resonant surface Second Harmonic Generation (SHG) effect. We consider two different layouts of planar microcavities with almost identical linear reflectance and show how the structure geometry can strongly affect SHG yield. In particular, a difference of more than one order of magnitude in the SHG intensity is observed when the fundamental beam is tuned at the cavity resonance frequency. We explain this finding on the basis of a theoretical model taking into account the spatial distribution of the electric fields of the pump and harmonic frequencies inside the structure. A satisfactory matching of experimental data with the theoretical model is obtained by considering the source of second-order nonlinearity as limited to surface contributions.

A new device for abrasive cytology sampling during upper gastrointestinal endoscopy: experience in infectious and neoplastic diseases

BACKGROUND AND STUDY AIMS

The increase in infectious diseases of the gastrointestinal tract related to immunosuppression is becoming an important topic for the endoscopist. To improve the diagnostic efficacy of tissue acquisition while at the same time restricting costs, we have developed a new device for obtaining material from the upper gastrointestinal tract that can also be used in the diagnosis of neoplastic disease.

PATIENTS AND METHODS

A total of 90 patients were examined and assigned to two groups according to indications. Group A consisted of 53 symptomatic patients with positive human immunodeficiency virus (HIV) serology with a suspicion of gastrointestinal infection. Group B included 37 patients in whom there was an endoscopic suspicion of neoplasia in the upper gastrointestinal tract. Cell fragments for cytological study were obtained using a device introduced through the endoscopic instrumentation channel (abrasive cytology). Different staining methods were used to isolate bacteria or diagnose tumors from cell fragments. The findings were compared with those obtained from conventional bioptic histology.

RESULTS

Potentially responsible pathogens were isolated in 48 of the 53 patients in Group A, while bioptic histology provided a diagnosis in only 32 patients. In the 37 patients in group B, the cytological diagnosis matched the histological results. The costs of this new technique are similar to those for conventional cytological staining, and the time from sampling to obtaining a final diagnosis is less than one hour.

CONCLUSIONS

This new device provides a fast and low-cost method of isolating pathogens and obtaining cell fragments from the gastrointestinal mucosa during routine upper gastrointestinal endoscopy.