Predictors of poor outcomes among patients treated for multidrug-resistant tuberculosis at DOTS-plus projects

The Objective of this analysis was to identify predictors of death, failure, and default among MDR-TB patients treated with second-line drugs in DOTS-plus projects in Estonia, Latvia, Philippines, Russia, and Peru, 2000-2004. Risk ratios (RR) with 95% confidence intervals (CI) were calculated using multivariable regression. Of 1768 patients, treatment outcomes were: cure/completed - 1156 (65%), died - 200 (11%), default - 241 (14%), failure - 118 (7%). Independent predictors of death included: age>45 years (RR?=?1.90 (95%CI 1.29-2.80), HIV infection (RR?=?4.22 (2.65-6.72)), extrapulmonary disease (RR?=?1.54 (1.04-2.26)), BMI<18.5 (RR?=?2.71 (1.91-3.85)), previous use of fluoroquinolones (RR?=?1.91 (1.31-2.78)), resistance to any thioamide (RR?=?1.59 (1.14-2.22)), baseline positive smear (RR?=?2.22 (1.60-3.10)), no culture conversion by 3rd month of treatment (RR?=?1.69 (1.19-2.41)); failure: cavitary disease (RR?=?1.73 (1.07-2.80)), resistance to any fluoroquinolone (RR?=?2.73 (1.71-4.37)) and any thioamide (RR?=?1.62 (1.12-2.34)), and no culture conversion by 3rd month (RR?=?5.84 (3.02-11.27)); default: unemployment (RR?=?1.50 (1.12-2.01)), homelessness (RR?=?1.52 (1.00-2.31)), imprisonment (RR?=?1.86 (1.42-2.45)), alcohol abuse (RR?=?1.60 (1.18-2.16)), and baseline positive smear (RR?=?1.35 (1.07-1.71)). Patients with biomedical risk factors for treatment failure or death should receive heightened medical attention. To prevent treatment default, management of patients who are unemployed, homeless, alcoholic, or have a prison history requires extra measures to insure treatment completion.     

From the Cover: Hemozoin-generated vapor nanobubbles for transdermal reagent- and needle-free detection of malaria

Successful diagnosis, screening, and elimination of malaria critically depend on rapid and sensitive detection of this dangerous infection, preferably transdermally and without sophisticated reagents or blood drawing. Such diagnostic methods are not currently available. Here we show that the high optical absorbance and nanosize of endogenous heme nanoparticles called “hemozoin,” a unique component of all blood-stage malaria parasites, generates a transient vapor nanobubble around hemozoin in response to a short and safe near-infrared picosecond laser pulse. The acoustic signals of these malaria-specific nanobubbles provided transdermal noninvasive and rapid detection of a malaria infection as low as 0.00034% in animals without using any reagents or drawing blood. These on-demand transient events have no analogs among current malaria markers and probes, can detect and screen malaria in seconds, and can be realized as a compact, easy-to-use, inexpensive, and safe field technology.Rapid, accurate, noninvasive, and bloodless detection of low levels of malaria parasites is critical for surveillance, treatment, and elimination of malaria (1, 2) but so far is not supported by current diagnostic methods (3–7), which depend upon qualified personnel, sophisticated in vitro methodologies, blood sampling, and specific reagents. All blood-stage malaria parasites digest hemoglobin and form unique intraparasite nanoparticles called “hemozoin” (8–11). The high optical absorbance combined with the nanosize (50–400 nm) of hemozoin (9, 11, 12) can be used to generate a transient localized vapor nanobubble around hemozoin in response to a short, safe laser pulse. A short picosecond pulse localizes the released heat to a nanovolume around a nanoparticle (13, 14) and evaporates liquid around the hemozoin in an explosive manner, creating an expanding and collapsing transient vapor bubble of submicrometer size in the malaria parasite (Fig. 1A). Using our experience in the generation and detection of vapor nanobubbles of other origins in cells and animals (15, 16), we hypothesized that hemozoin-induced vapor nanobubbles (H-VNBs) can act as highly sensitive optical and acoustic probes for malaria detection (Fig. 1 B and C). Here, we report studies of H-VNBs in water, whole blood, and individual human red blood cells (RBCs) infected with Plasmodium falciparum and evaluate their noninvasive transdermal detection in Plasmodium yoelii–infected mice.Open in a separate windowFig. 1.(A) Laser-induced generation of a transient H-VNB around hemozoin nanoparticles inside a malaria parasite within the iRBC. Detection of optical scattering signals of the nanobubble with an optical detector (OD) (B) and (C) pressure pulse of the H-VNB detected with an ultrasound transducer (UT) as an acoustic trace.     

From the Cover: Distinctive properties of identical twins' TCR repertoires revealed by high-throughput sequencing

Adaptive immunity in humans is provided by hypervariable Ig-like molecules on the surface of B and T cells. The final set of these molecules in each organism is formed under the influence of two forces: individual genetic traits and the environment, which includes the diverse spectra of alien and self-antigens. Here we assess the impact of individual genetic factors on the formation of the adaptive immunity by analyzing the T-cell receptor (TCR) repertoires of three pairs of monozygous twins by next-generation sequencing. Surprisingly, we found that an overlap between the TCR repertoires of monozygous twins is similar to an overlap between the TCR repertoires of nonrelated individuals. However, the number of identical complementary determining region 3 sequences in two individuals is significantly increased for twin pairs in the fraction of highly abundant TCR molecules, which is enriched by the antigen-experienced T cells. We found that the initial recruitment of particular TCR V genes for recombination and subsequent selection in the thymus is strictly determined by individual genetic factors. J genes of TCRs are selected randomly for recombination; however, the subsequent selection in the thymus gives preference to some α but not β J segments. These findings provide a deeper insight into the mechanism of TCR repertoire generation.Adaptive immunity is provided by B and T cells bearing B-cell receptors (BCRs) and Ig-like T-cell receptors (TCRs), respectively. These hypervariable molecules are the key part of the adaptive immune system as they can potentially recognize any alien agent and drive specific immune responses. The α/β TCRs recognize short peptides in the complex with major histocompatibility complex (MHC) molecules and play the key role in the targeted immune response. The total diversity of TCR molecules in an individual human organism is initially formed via genomic recombination with subsequent positive and negative selection at several stages of maturation and activation. The maximal theoretical diversity of TCRβ chain’s amino acid sequences in humans is estimated between 5 × 10¹¹ (1) and 10¹⁴ (2), whereas the maximal number of α/β pairs reaches 10¹⁸ (3). This huge number of variants is probably never achieved: the whole TCRβ chain repertoire size in a single human organism is estimated at 1–5 × 10⁶ (1, 4–6), although this is only a lower bound estimate. Two driving forces shape the final face of individual TCR repertoire: the individual genetics and the complexity of environmental factors. The genes coding for proteins involved in VDJ recombination, antigen processing and presentation, and products of genes participating in the immune response signaling belong to the first type of the repertoire-forming factors. The spectrum of the organism’s self-peptides presented in the thymus also depends on the individual’s set of the MHC molecules. Moreover, this spectrum of peptides is determined by the amino acid sequences of the organism’s proteins, which thus can also be considered a genetic factor. Furthermore, TCRs arising to the same alien antigenic peptides are known to be MHC restricted (7). The environmental factors include the whole range of pathogens met by the individual including disease-causing bacteria and viruses, as well as vaccines, symbionts, etc. The genetic component can potentially have a major impact on the initial recombination and selection in the thymus forming the naïve TCR repertoire, whereas the subsequent interference with antigens provides the selective expansion of some TCRs and forms the final repertoire structure. However, the particular impact of genetic factors on TCR repertoire structure and diversity is unknown.All genes of monozygous (MZ) twins are identical (including those responsible for the TCR repertoire formation), and therefore, MZ twins are widely used in the studies where the genetic impact is evaluated. Several studies of TCR repertoires were performed mainly focusing on diseases concordant and discordant MZ twins and using complementarity determining region 3 (CDR3) spectra-typing and/or low depth sequencing (8–11). Some of these studies reported the common use of particular V genes and common clonotypes. In recent years, the high-throughput sequencing technologies paved the way to whole-repertoire studies of individual TCRs that led to new findings in the field of adaptive immunity (1, 5, 6, 12–22). In this study, for the first time to the best of our knowledge, we obtain and compare the α and β chain TCR repertoires of three pairs of MZ twins using next-generation sequencing (NGS).     

LIPS method for the detection of SARS-CoV-2 antibodies to spike and nucleocapsid proteins

Profiling antibodies to SARS-CoV-2 can help to assess potential immune response after COVID-19 disease. Luciferase IP system (LIPS) assay is a sensitive method for quantitative detection of antibodies to antigens in their native conformation. We here describe LIPS to detect antibody responses to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in COVID-19 patients. The antibodies targeted both S and N fragments and gave a high assay sensitivity by identifying 26 out of 26 COVID-19 patients with N antigen or with three protein fragments when combined into a single reaction. The assay correlated well with ELISA method and was specific to COVID-19 as we saw no reactivity among uninfected healthy controls. Our results show that LIPS is a rapid and measurable method to screen antibody responses against SARS-CoV-2 antigens.     

Structure and excitation-dependent emission of novel zinc complexes with pyridyltriazoles

A series of Zn(ii) complexes with 5-(4-R-phenyl)-3-(pyridin-2-yl)-1,2,4-triazoles have been synthesized and subsequently characterized by single crystal X-ray diffraction, ¹H-NMR, FT-IR spectroscopy, elemental analyses, ESI-MS, and PXRD. The X-ray diffraction analyses revealed that the complexes have a similar molecular structure and their supramolecular frameworks are constructed by hydrogen bonds and π⋯π interaction scaffolds. Upon irradiation with UV light, the studied complexes display deep blue emission at 396–436 nm in the solid state. The compounds show an unexpected excitation-dependent emission phenomenon which is detected by a change in the emission color (from blue to yellow) upon increase of the excitation wavelength. The conducted quantum-chemical calculations indicate that supramolecular differences in the single-crystal architecture of the synthesized complexes play a crucial role for this photophysical behaviour.

A series of Zn(ii) complexes with 5-(4-R-phenyl)-3-(pyridin-2-yl)-1,2,4-triazoles have been synthesized and subsequently characterized by single crystal X-ray diffraction, ¹H-NMR, FT-IR spectroscopy, elemental analyses, ESI-MS, and PXRD.     

Current Understanding of Central Nervous System Drainage Systems: Implications in the Context of Neurodegenerative Diseases

Until recently, it was thought that there were no lymphatic vessels in the central nervous system (CNS). Therefore, all metabolic processes were assumed to take place only in the circulation of the cerebrospinal fluid (CSF) and through the blood-brain barrier’s (BBB), which regulate ion transport and ensure the functioning of the CNS. However, recent findings yield a new perspective: There is an exchange of CSF with interstitial fluid (ISF), which is drained to the paravenous space and reaches lymphatic nodes at the end. This circulation is known as the glymphatic system. The glymphatic system is an extensive network of meningeal lymphatic vessels (MLV) in the basal area of the skull that provides another path for waste products from CNS to reach the bloodstream. MLV develop postnatally, initially appearing around the foramina in the basal part of the skull and the spinal cord, thereafter sprouting along the skull’s blood vessels and spinal nerves in various areas of the meninges. VEGF-C protein (vascular endothelial growth factor), expressed mainly by vascular smooth cells, plays an important role in the development of the MLV. The regenerative potential and plasticity of MLV and the novel discoveries related to CNS drainage offer potential for the treatment of neurodegenerative diseases such as dementia, hydrocephalus, stroke, multiple sclerosis, and Alzheimer disease (AD). Herein, we present an overview of the structure and function of the glymphatic system and MLV, and their potential involvement in the pathology and progression of neurodegenerative diseases.     

Indocyanine green dye based bimodal contrast agent tested by photoacoustic/fluorescence tomography setup

Multimodal imaging systems are in high demand for preclinical research, experimental medicine, and clinical practice. Combinations of photoacoustic technology with other modalities including fluorescence, ultrasound, MRI, OCT have been already applied in feasibility studies. Nevertheless, only the combination of photoacoustics with ultrasound in a single setup is commercially available now. A combination of photoacoustics and fluorescence is another compelling approach because those two modalities naturally complement each other. Here, we presented a bimodal contrast agent based on the indocyanine green dye (ICG) as a single signalling compound embedded in the biocompatible and biodegradable polymer shell. We demonstrate its remarkable characteristics by imaging using a commercial photoacoustic/fluorescence tomography system (TriTom, PhotoSound Technologies). It was shown that photoacoustic signal of the particles depends on the amount of dye loaded into the shell, while fluorescence signal depends on the total amount of dye per particle. For the first time to our knowledge, a commercial bimodal photoacoustic/fluorescence setup was used for characterization of ICG doped polymer particles. Additionally, we conducted cell toxicity studies for these particles as well as studied biodistribution over time in vivo and ex vivo using fluorescent imaging. The obtained results suggest a potential for the application of biocompatible and biodegradable bimodal contrast agents as well as the integrated photoacoustic/fluorescence imaging system for preclinical and clinical studies.