SARS-CoV-2 infection does not induce HIV viral escape in the central nervous system: A case series.

We report two cases of HIV positive patients with SARS-CoV-2 infection and a recent diagnosis of opportunistic infections of central nervous system (CNS). We investigated the potential impact of coinfection with SARS-CoV-2 on HIV replication in CNS.

Validation of a short questionnaire to record adherence to the Mediterranean diet: An Italian experience.

BACKGROUND AND AIMS: A greater adherence to the Mediterranean diet has been associated with a reduced risk of major chronic diseases and cancer. The aim of the study was to assess the validity of a new short self-administered 15-item questionnaire (QueMD) to measure adherence to the Mediterranean diet in Italy. METHODS AND RESULTS: Four-hundred and eighty three participants to cancer-screening programmes at the European Institute of Oncology, Milan (Italy) were invited to join this study. Those interested compiled the QueMD and a validated Food Frequency Questionnaire (FFQ) reporting their usual food consumption during the previous six months. We derived the alternate Mediterranean score (aMED) from both questionnaires with values ranging from 0 (minimal adherence) to 9 (maximal adherence). Complete dietary data were available for 343 individuals (participation rates 71.0%). Spearman correlation coefficient between the responses to the 15 questions of the QueMD and corresponding food intake derived from the FFQ ranged from 0.15 to 0.84. A moderate correlation was found between the aMED scores calculated from the QueMD and the FFQ (intraclass correlation coefficient 0.50; 95% CI, 0.42-0.58), while agreement between the two instruments was only poor to fair for 7 of the 9 single items composing the aMED score, with values ranging from 53.0% for wholegrain products to 79.5% for fruits. CONCLUSION: This new self-administered 15-item questionnaire could be a useful tool to assess adherence to the Mediterranean diet in the Italian population.

Quasi-distributed and wavelength selective addressing of optical micro-resonators based on long period fiber gratings.

A novel all-in-fiber method for coupling light to high-Q silica whispering gallery mode (WGM) optical micro-resonators is presented, which is based on a pair of long period fiber gratings (LPGs) written in the same silica fiber, along with a thick fiber taper (15-18 µm in waist) in between the LPGs. The proposed coupling structure is robust and can be replicated many times along the same fiber simply cascading LPGs with different bands. Typical Q-factors of the order of 10(8) and total coupling efficiency up to 60% were measured collecting the resonances of microspheres or microbubbles at the fiber end. This approach uniquely allows quasi-distributed and wavelength selective addressing of different micro-resonators along the same fiber.

Towards sensitive label-free immunosensing by means of turn-around point long period fiber gratings.

Long period fiber gratings have been effectively used in the field of biochemical sensing since a few years. Compared to other well-known label-free optical approaches, long period gratings (LPGs) take advantage of the typical peculiarity of optical fibers. Coupling the propagating core mode with a high-order cladding mode near its turn-around point (TAP) was the strategy adopted to achieve good performances without additional coatings, except for the sensing and selective biolayer deposited on the fiber. Both the modeling and manufacturing of TAP LPGs were discussed. After the functionalization of the fiber surface with the deposition of a Eudragit L100 copolymer layer followed by immunoglobulin G (IgG) covalent immobilization, an IgG/anti-IgG bioassay was implemented along the grating region and the kinetics of antibody/antigen interaction was analyzed. A quantitative comparison between a TAP LPG and a non-TAP LPG was carried out to highlight the improvement of the proposed immunosensor. The real effectiveness and feasibility of an LPG-based biosensor were demonstrated by using a complex matrix consisting of human serum, which also confirmed the specificity of the assay, and a limit of detection of 70 µg L(-1) (460 pM) was achieved.

Oligonucleotide optical switches for intracellular sensing.

Fluorescence imaging coupled with nanotechnology is making possible the development of powerful tools in the biological field for applications such as cellular imaging and intracellular messenger RNA monitoring and detection. The delivery of fluorescent probes into cells and tissues is currently receiving growing interest because such molecules, often coupled to nanodimensional materials, can conveniently allow the preparation of small tools to spy on cellular mechanisms with high specificity and sensitivity. The purpose of this review is to provide an exhaustive overview of current research in oligonucleotide optical switches for intracellular sensing with a focus on the engineering methods adopted for these oligonucleotides and the more recent and fascinating techniques for their internalization into living cells. Oligonucleotide optical switches can be defined as specifically designed short nucleic acid molecules capable of turning on or modifying their light emission on molecular interaction with well-defined molecular targets. Molecular beacons, aptamer beacons, hybrid molecular probes, and simpler linear oligonucleotide switches are the most promising optical nanosensors proposed in recent years. The intracellular targets which have been considered for sensing are a plethora of messenger-RNA-expressing cellular proteins and enzymes, or, directly, proteins or small molecules in the case of sensing through aptamer-based switches. Engineering methods, including modification of the oligonucleotide itself with locked nucleic acids, peptide nucleic acids, or L-DNA nucleotides, have been proposed to enhance the stability of nucleases and to prevent false-negative and high background optical signals. Conventional delivery techniques are treated here together with more innovative methods based on the coupling of the switches with nano-objects.

Optofluidic microsystems with integrated vertical one-dimensional photonic crystals for chemical analysis.

In this work, we report all-silicon, integrated optofluidic microsystems (OFMs) fabricated by electrochemical micromachining (ECM) technology, in which high aspect-ratio (HAR) photonic crystal (PhC) devices (i.e. micromirrors, optical cavities) are integrated by one-etching-step, together with microfluidic reservoirs/channels, for the infiltration of liquids in the PhC air gaps, and with fiber grooves for alignment/positioning of readout optical fibers in front of the PhC, on the same silicon die. This has not previously been reported in the literature, and opens up new ground in, though not limited to, the optofluidics field, due to the low-cost and high-flexibility of the ECM technology that allows optofluidic microsystem fabrication to be performed in any lab. Optofluidic characterization of PhC-OFMs by both capillary-action and pressure-driven operations is carried out through the measurement of the reflectivity spectra of HAR-PhCs upon injection of liquids featuring different refractive index values in the HAR-PhC air gaps, by using readout optical fibers positioned in the on-chip fiber grooves. High sensitivity and good limit of detection of PhC-OFMs are obtained for both capillary-action and pressure-driven operations. A best sensitivity value of 670 nm/RIU and a worst-case limit of detection of the order of 10(-3) RIU are measured, the former being comparable to state-of-the-art integrated refractive index sensors and the latter being limited by constraints of the experimental setup. The proof of concept about the biosensing potential of PhC-OFMs is given by successfully carrying out a sandwich assay based on antigen-antibody interactions for the detection of the C-reactive protein (CRP) at a concentration value of 10 mg L(-1), which represents the boundary level between physiological and pathological conditions.

Optical fibre gratings as tools for chemical and biochemical sensing.

Optical fibre gratings have recently been suggested as optical platforms for chemical and biochemical sensing. On the basis of the measurement of refractive index changes induced by a chemical and biochemical interaction in the transmission spectrum along the fibres, they are proposed as a possible alternative to the other label-free optical approaches, such as surface plasmon resonance and optical resonators. The combination of the use of optical fibres with the fact that the signal modulation is spectrally encoded offers multiplexing and remote measurement capabilities which the other technology platforms are not able to or can hardly offer. The fundamentals of the different types of optical fibre gratings are described and the performances of the chemical and biochemical sensors based on this approach are reviewed. Advantages and limitations of optical fibre gratings are considered, with a look at new perspectives for their utilization in the field.

Acute HIV infection: a misleading presentation.

Detecting acute HIV infection is important, but often the infection is difficult to recognize. We report the case of a 23-year-old man with persistent genital ulceration; all microbiological examinations from the ulcers were negative. HIV-1/2 antibodies were positive, but the HIV-1 Western blot (WB) was indeterminate and HIV-1 p24 antigen was persistently negative, with a low HIV-1 RNA level. One month later, the genital ulcerations disappeared and the WB test showed complete seroconversion; nonetheless HIV p24 antigen remained negative and HIV-RNA was persistently low. HIV-1 proviral DNA was detected by nested polymerase chain reaction (PCR) from the initial ulcers swabs. This case was notable due to genital ulceration being the only sign of primary HIV infection. Furthermore, the serological pattern was unusual, and HIV-RNA was unexpectedly low. This underlines the importance of screening for HIV being infection in the setting of sexually transmitted infections (STIs), and also in cases of atypical STI-like presentations.

Microdialysis-based sensing in clinical applications.

The need for fast and continuous measurements in the biomedical field is driving scientists to look for an alternative to blood sampling. This implies the adoption of invasive approaches, which, in some cases, may lead to reduced safety for the patient; consequently this strategy is pursued only if it is unavoidable. Microdialysis-based sensing provides a minimally invasive solution, with biological samples drawn by means of a microdialysis catheter and examined outside the human body. Therefore, it has become a promising approach to investigate the interstitial fluid in human brain and subcutaneous adipose tissue, providing important information on the tissue biochemistry and metabolism. Advantages and limitations of microdialysis are considered here and the applications in the clinical field are described, with the provision of some examples and with a view to the new perspectives in the field.

High-Q polymer-coated microspheres for immunosensing applications.

Homogeneous polymeric thin layers have been used as functionalizing agents on silica microspherical resonators in view of the implementation of an immunosensor. We have characterized the microspheres functionalized with poly-L-lactic acid and Eudragit L100, as an alternative to the commonly used 3-Aminopropyltrimethoxysilane. It is shown that polymeric functionalization does not affect the high quality factor (Q greater than 10(7)) of the silica microspheres, and that the Q factor is about 3 x 10(5) after chemical activation and covalent binding of immunogammaglobulin (IgG). This functionalizing process of the microresonator constitutes a promising step towards the achievement of an ultra sensitive immunosensor.

A new procalcitonin optical immunosensor for POCT applications.

A new immunosensor for the determination of procalcitonin was developed. A sandwich assay format was implemented on a polymethylmetacrylate optical biochip, opportunely shaped in order to obtain several flow channels and potentially suitable for point of care testing applications. The sandwich format makes use of two new rat monoclonal antibodies. The capture antibody was covalently immobilised on the surface of the plastic chip, and the detection antibody was labelled with DY647 dye. Different combinations of capture and detection antibodies were investigated, and particular attention was devoted in order to avoid the non-specific adsorption. A limit of detection of 0.088 mg L(-1) was achieved within the working range of 0.28-50 mg L(-1) in buffer samples. The assay was also implemented in human serum, and 0.2 and 0.7-25 mg L(-1) were the attained limit of detection and working range, respectively.

A new optical platform for biosensing based on fluorescence anisotropy.

A novel fluorescence-based optical platform for the interrogation of an optical biochip was designed and developed. The optical biochip was made of poly(methyl methacrylate) (PMMA) formed by two pieces of PMMA appropriately shaped in order to obtain four microchannels that are 500-microm wide and 400-microm high. The lower part includes the microchannels and the inlet and outlet for the fluidics, while the sensing biolayer was immobilized on the upper part. The optical signal comprised the fluorescence emitted by the biolayer, which was anisotropically coupled to the PMMA cover and suitably guided by the PMMA chip. The potentiality of the optical chip as a biosensor was investigated by means of a direct IgG/anti-IgG interaction carried out inside the flow channels. The mouse-IgG was covalently immobilized on the internal wall of the PMMA cover, and the Cy5-labelled anti-mouse IgG was used for the specific interaction. Several chemical treatments of the PMMA surface were investigated, poly(L: -lactic acid), Eudragit L100 and NaOH, in order to obtain the most effective distribution of carboxylic groups useful for the covalent immobilisation of the mouse-IgG. The treatment with Eudragit L100 was found to be the most successful. Limits of detection and quantification of 0.05 microg mL(-1) and 0.2 microg mL(-1), respectively, were obtained with the configuration described.

Wheelchair racing efficiency.

PURPOSE: For individuals with disabilities exercise, such as wheelchair racing, can be an important modality for community reintegration, as well as health promotion. The purpose of this study was to examine selected parameters during racing wheelchair propulsion among a sample of elite wheelchair racers. It was hypothesized that blood lactate accumulation and wheeling economy (i.e. oxygen consumed per minute) would increase with speed and that gross mechanical efficiency would reach an optimum for each athlete. METHOD: Twelve elite wheelchair racers with paraplegia participated in this study. Nine of the subjects were males and three were females. Each subject used his or her personal wheelchair during the experiments. A computer monitored wheelchair dynamometer was used during all testing. The method used was essentially a discontinuous economy protocol. Mixed model analysis of variance (ANOVA) was used to compare blood lactate concentration, economy (minute oxygen consumption), and gross mechanical efficiency across the stages. RESULTS: The results of this study show that both economy and blood lactate concentration increase linearly with speed if resistance is held constant. The subjects in this study had gross mechanical efficiencies (gme) of about 18%, with the range going from 15.222.7%. The results indicate that at the higher speeds of propulsion, for example near race speeds, analysis of respiratory gases may not give a complete energy profile. CONCLUSION: While there is a good understanding of training methods to improve cardiovascular fitness for wheelchair racers, little is known about improving efficiency (e.g. technique, equipment), therefore methods need to be developed to determine efficiency while training or in race situations.

Female sex and the use of anti-allergic agents increase the risk of developing cutaneous rash associated with nevirapine therapy.

To identify factors associated with cutaneous rash, we performed a retrospective multicentre analysis of HIV outpatients starting a highly active antiretroviral therapy regimen containing nevirapine. A total of 62 cutaneous adverse events were observed in 429 patients. Rash hazard was increased in women, by the prophylactic use of glucocorticoids or antihistaminics, and was reduced by escalating the initial dose of nevirapine. Women receiving glucocorticoids had a 3 month cumulative probability of rash of 0.41.

Physiological responses to two wheelchair-racing exercise protocols.

OBJECTIVE: This study investigated the blood lactate accumulation during two wheelchair-racing protocols. During exercise, energy is required, which causes metabolism to increase and blood lactate to accumulate. Proper training can reduce the amount of blood lactate accumulation and increase tolerance to blood lactate accumulation during aerobic exercise. METHODS: Eleven male wheelchair elite track athletes with a spinal cord injury were tested to determine their blood lactate response to speed and resistance workouts. A computer-monitored wheelchair dynamometer was used during all exercise tests. The order of the test (e.g., speed or resistance workout) was randomized. Blood pressure and blood samples were taken immediately before and after completion of each exercise test. RESULTS: The difference between the blood lactate concentrations before and after testing were 8.56 +/- 4.42, and 11.67 +/- 4.69 mM for the resistance and speed tests, respectively. CONCLUSIONS: Our results showed that the blood lactate responses were significantly different for the resistance and speed workouts.

Analysis of the optical properties of bile.

Invasive bile determination is very useful in the diagnosis of many gastric pathologies. At the moment, this measurement is performed with Bilitec 2000, an optical fiber sensor, that is based on absorption by bilirubin. Nevertheless, erroneous evaluations are possible, due to the different configurations which the bilirubin molecule can adopt. The optical behavior of human samples of pure bile and bile+gastric juice has been examined using an optical fiber spectrophotometer and two suitably modified Bilitec 2000 units. A protocol has been established for the treatment of biological fluids, in order to make it possible to study the behavior of their optical properties as a function of pH and concentration without causing any alteration in the samples. The analysis of pH dependence evidenced the presence of different calibration curves at different pH values: the self-aggregation of the bilirubin molecules observed in pure bile samples was almost totally absent in the gastric samples. Measurements carried out on Bilitec 2000 showed that the most appropriate wavelength for bilirubin detection in the stomach should be 470 nm.