May I Help You with Your Coat? HIV-1 Capsid Uncoating and Reverse Transcription.

The human immunodeficiency virus type 1 (HIV-1) capsid is a protein core formed by multiple copies of the viral capsid (CA) protein. Inside the capsid, HIV-1 harbours all the viral components required for replication, including the genomic RNA and viral enzymes reverse transcriptase (RT) and integrase (IN). Upon infection, the RT transforms the genomic RNA into a double-stranded DNA molecule that is subsequently integrated into the host chromosome by IN. For this to happen, the viral capsid must open and release the viral DNA, in a process known as uncoating. Capsid plays a key role during the initial stages of HIV-1 replication; therefore, its stability is intimately related to infection efficiency, and untimely uncoating results in reverse transcription defects. How and where uncoating takes place and its relationship with reverse transcription is not fully understood, but the recent development of novel biochemical and cellular approaches has provided unprecedented detail on these processes. In this review, we present the latest findings on the intricate link between capsid stability, reverse transcription and uncoating, the different models proposed over the years for capsid uncoating, and the role played by other cellular factors on these processes.

A history of adjustment disorder predicts greater weight loss after sleeve gastrectomy.

BACKGROUND: Bariatric surgery is one of the most effective long-term options for treating class III obesity or class II obesity with medical co-morbidities; however, a significant number of patients do not achieve the expected weight loss. New studies are needed to find the predictive value of different variables on surgery outcomes. OBJECTIVES: Our aim was to study a number of physical, medical, and psychopathological variables as potential risk factors for poor outcomes in patients with class II-IV obesity scheduled for sleeve gastrectomy. SETTING: Sagrat Cor University Hospital in Barcelona, Spain. METHODS: This prospective longitudinal study enrolled a sample consisting of 441 patients from whom a descriptive analysis was obtained. For 235 of them, we performed a comparative analysis between the patients with differing responses to sleeve gastrectomy after 1 year of follow-up. The remaining patients had differing follow-up data or were lost to follow-up. To collect the data, a semi-structured interview was conducted, and various tests were administered to assess the patients' psychopathology (Hamilton Rating Scale for Depression, Hamilton Anxiety Rating Scale) and functionality (Global Assessment of Functioning Scale). RESULTS: The results show the prognostic relationship between certain presurgery variables and the good or poor outcomes of the bariatric surgery, based on the patients' weight loss. Advanced age, high body mass index, diabetes, and respiratory problems were significant predictors of a poor response to surgery. Contrarywise, a history of adjustment disorder predicted a better response. CONCLUSIONS: The results allow us to conclude that, beyond well-established physical and medical conditions, a psychopathological study of patients prior to bariatric surgery including adjustment disorders could be predictive of therapeutic response and could help to personalize the follow-up.

Progressive Functional and Neuroretinal Affectation in Patients With Multiple Sclerosis Treated With Fingolimod.

BACKGROUND: To evaluate the effect of fingolimod in visual function and neuroretinal structures in patients with multiple sclerosis (MS) for a period of 1 year. METHODS: This longitudinal and observational cohort study included 78 eyes of 78 patients with MS treated with fingolimod. All subjects were evaluated every 3 months during 12 months and compared with 32 patients treated with interferon beta. All patients were examined for high-contrast and low-contrast (2.5% and 1.25%) visual acuity (VA), contrast sensitivity vision (CSV) (using Pelli-Robson and CSV-1000E tests), color vision (Farnsworth D-15 and L'Anthony D-15 desaturated tests), and retinal structural measurements (retinal nerve fiber layer [RNFL] and ganglion cell layer [GCL] thickness) using optical coherence tomography (OCT) technology. RESULTS: Patients with MS treated with fingolimod for a period of 1 year showed significant reduction in 100% and 1.25% contrast VA (P = 0.009 and 0.008, respectively), an alteration of contrast sensitivity and color perception (Pelli-Robson test, CSV-1000E test, Farnsworth D-15 desaturated test, and L'Anthony D-15 desaturated test; P < 0.001), GCL thickness reduction (P = 0.007), and an average macular central thickness increase of 2.6 µm (P = 0.006). Patients with MS treated with interferon beta did not show significant changes in visual function tests neither in macular thickness measurements, but they showed a significant reduction in GCL and RNFL thicknesses. The reduction in neuroretinal structures observed by OCT was significantly higher in the interferon-beta group, but patients treated with fingolimod showed a significant increase in macular central thickness and a reduction in low contrast vision (P < 0.001). CONCLUSIONS: Patients with MS treated with fingolimod and with no clinically observable macular edema show a significant change in visual function parameters and average macular central thickness increase compared with those treated with interferon beta. These findings are probably due to subclinical macular edema produced by fingolimod, which might be considered as an indicator for pharmacovigilance of sphingosine-1-phosphate inhibitors to be improved.

Ability of Swept source OCT technology to detect neurodegeneration in patients with type 2 diabetes mellitus without diabetic retinopathy.

PURPOSE: To evaluate neurodegeneration in patients with type 2 Diabetes Mellitus (DM2) without diabetic retinopathy, and to assess the possible role of chronic systemic ischaemia and disease duration in retinal changes. STUDY DESIGN: Observational cross sectional study. METHODS: Sixty eyes of 60 patients with DM2 without signs of diabetic retinopathy (DR), and 60 eyes of 60 healthy controls underwent retinal (ganglion cell layer (GCL), and retinal nerve fiber layer (RNFL) and choroidal evaluation using Swept source Optical coherence tomography, which allows high quality analysis of the different retinal layers and the choroidal plexus. Comparison between patients with presence/absence of systemic vascular complications and different disease duration time was performed. RESULTS: Macular GCL and RNFL were reduced in patients compared to controls (p < 0.001). In the peripapillary area, a reduction of the RNFL (p < 0.001) was observed in patients with DM2. There were no significant changes observed in the choroidal plexus of these patients. Patients with systemic ischaemia presented significant thinning of the choroid and further reduction of the temporal RNFL (p = 0.014) and GCL (p = 0.016) thickness. The GCL and the choroid were also thinner in patients with longer disease duration. CONCLUSIONS: Patients with early DM2 present retinal neurodegeneration prior to the appearance of clinically observable vascular retinal changes. In these patients chronic systemic ischaemia caused reduction of the choroidal plexus and further damage to the retinal layers, adding new information on systemic chronic ischaemia and retinal neurodegeneration in patients with DM2 without DR.

Neurodegeneration in Patients with Type 2 Diabetes Mellitus without Diabetic Retinopathy.

PURPOSE: To evaluate neurodegeneration in patients with type 2 diabetes mellitus (DM2) without diabetic retinopathy and to assess the possible role of systemic vascular complications in retinal changes. METHODS: Sixty eyes of 60 patients with DM2 and without any signs of diabetic retinopathy and 60 eyes of 60 healthy controls underwent retinal evaluation using Spectralis optical coherence tomography. Macular ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL) were evaluated. Peripapillary RNFL thickness was assessed using Glaucoma and Axonal Analytics applications. Comparison between patients with the presence/absence of systemic vascular complications and different disease duration was made. RESULTS: Macular GCL was reduced in patients compared to controls (p < 0.001). Differences in the macular RNFL thickness were only observed in the outer inferior sector (p=0.033). A reduction in the peripapillary RNFL (average, inferior, and inferotemporal thickness, p < 0.05 for all three) was observed in patients using both applications. Patients with chronic systemic vascular complications presented a reduction in the temporal RNFL (p=0.019) compared to patients without complications. The superotemporal RNFL thickness was thinner in patients with longer disease duration. CONCLUSIONS: Patients with type 2 DM without diabetic retinopathy and good metabolic control present neurodegeneration affecting neurons in the macular area and axons in different sectors of the optic disc. Systemic vascular complications contributed to further axonal damage in these patients, suggesting a possible role of subclinical ischaemia to retinal neurodegeneration in type 2 DM.

Diffusion Tensor Imaging Measures of Brain Connectivity for the Early Diagnosis of Alzheimer's Disease.

The prognostic capacity of the diffusion tensor imaging measures fractional anisotropy (FA) and mean diffusivity (MD) to detect mild cognitive impairment (MCI) progression to Alzheimer's disease (AD) was assessed in 135 MCI patients and 72 healthy subjects over a median follow-up of 40 months. Forty-nine MCI patients (36.3%) developed AD. The factors MD left hippocampus, FA left cingulate, and FA left hippocampus emerged as predictors of progression. Age (hazard ratio [HR] 1.21), delayed text recall (HR 0.89), FA left uncinate (HR 1.90), FA left hippocampus (HR 2.21), and carrying at least one ApoE4 allele (HR 2.86) were associated with a high conversion rate. FA measures revealed the greatest discriminative capacity (Harrell's C = 0.73 versus 0.65 without FA; p = 0.034). The inclusion of FA structural connectivity data in our model improved discrimination between subjects with MCI progressing or not to dementia.

Retinal and Optic Nerve Degeneration in Patients with Multiple Sclerosis Followed up for 5 Years.

PURPOSE: To quantify retinal nerve fiber layer (RNFL) changes in patients with multiple sclerosis (MS) and healthy controls with a 5-year follow-up and to analyze correlations between disability progression and RNFL degeneration. DESIGN: Observational and longitudinal study. PARTICIPANTS: One hundred patients with relapsing-remitting MS and 50 healthy controls. METHODS: All participants underwent a complete ophthalmic and electrophysiologic exploration and were re-evaluated annually for 5 years. MAIN OUTCOME MEASURES: Visual acuity (Snellen chart), color vision (Ishihara pseudoisochromatic plates), visual field examination, optical coherence tomography (OCT), scanning laser polarimetry (SLP), and visual evoked potentials. Expanded Disability Status Scale (EDSS) scores, disease duration, treatments, prior optic neuritis episodes, and quality of life (QOL; based on the 54-item Multiple Sclerosis Quality of Life Scale score). RESULTS: Optical coherence tomography (OCT) revealed changes in all RNFL thicknesses in both groups. In the MS group, changes were detected in average thickness and in the mean deviation using the GDx-VCC nerve fiber analyzer (Laser Diagnostic Technologies, San Diego, CA) and in the P100 latency of visual evoked potentials; no changes were detected in visual acuity, color vision, or visual fields. Optical coherence tomography showed greater differences in the inferior and temporal RNFL thicknesses in both groups. In MS patients only, OCT revealed a moderate correlation between the increase in EDSS and temporal and superior RNFL thinning. Temporal RNFL thinning based on OCT results was correlated moderately with decreased QOL. CONCLUSIONS: Multiple sclerosis patients exhibit a progressive axonal loss in the optic nerve fiber layer. Retinal nerve fiber layer thinning based on OCT results is a useful marker for assessing MS progression and correlates with increased disability and reduced QOL.

Electrochemically Active Thin Carbon Films with Enhanced Adhesion to Silicon Substrates.

Thin carbon films deposited on technologically relevant substrates, such as silicon wafers, can be easily implemented in miniaturized electrochemical devices and used for sensing applications. However, a major issue in most carbon films is the weak film/substrate adhesion that shortens the working device lifetime. This paper describes the facile preparation of robust thin carbon films on silicon substrates by one-pot sol-gel synthesis. The improved adherence of these carbon films is based on the incorporation of silica through the controlled synthesis of a resorcinol/formaldehyde gel modified with aminopropyltriethoxysilane. The films demonstrate excellent adhesion to the silicon substrate, good homogeneity, excellent electrical conductivity and superior electrochemical performance. Moreover, this approach opens the door to the fabrication of carbon thin-film electrodes by photolithographic techniques.

Cytochrome P450 2D6 based electrochemical sensor for the determination of codeine.

Considering the enzymatic activity of the cytochrome P450 2D6 on substrates such as codeine, the current paper includes the development of an enzymatic biosensor for detection of this drug. Home-made screen-printed electrodes were used as electrochemical transducers of the biosensor, in which the enzyme was covalently attached to the carbon surface of the working electrode, this type of modification being the most suitable for the immobilization of the biological element. Chronoamperometric measurements were carried out under optimum conditions of pH and working potential, pH 7 and +200 mV vs. screen-printed Ag/AgCl electrode, giving a reduction signal related to the concentration of codeine in solution. Consecutive additions of a solution of codeine were performed to obtain calibration curves in order to validate the electrochemical method in terms of precision and calculate its capability of detection. These biosensors were used for the determination of codeine in urine and commercial pharmaceutical samples.

Sensitive and selective cocaine electrochemical detection using disposable sensors.

This paper describes the voltammetric determination of cocaine in presence of three different interferences that could be found in street samples using disposable sensors. The electrochemical analysis of this alkaloid can be affected by the presence of codeine, paracetamol or caffeine, whose oxidation peaks may overlap and lead to false positives. This work describes two different solutions to this problem. On one hand, the modification of disposable carbon sensors with carbon nanotubes allows the voltammetric quantification of cocaine by using ordinary least squares regressions in the concentration range from 10 to 155 µmol L(-1), with a reproducibility of 5.6% (RSD, n = 7. On the other hand, partial least squares regressions are used for the resolution of the overlapped voltammetric signals when using screen-printed carbon electrodes without any modification. Both procedures have been successfully applied to the evaluation of the purity of cocaine street samples.

Effect of cataract surgery on optical coherence tomography measurements and repeatability in patients with non-insulin-dependent diabetes mellitus.

PURPOSE: To evaluate the effect of uncomplicated cataract phacoemulsification on macular and retinal nerve fiber layer (RNFL) thickness using two spectral-domain optical coherence tomography (OCT) instruments, Cirrus OCT and Spectralis OCT, in patients having non-insulin-dependent diabetes mellitus (NIDDM) without retinopathy, and to assess the reliability of the OCT measurements before and after cataract surgery. METHODS: The study included 35 eyes of 35 patients having NIDDM without retinopathy (20 men and 15 women, mean age 69.8 years, range, 48-80 years) who underwent cataract phacoemulsification. One month before and 1 month after surgery, visual acuity and three repetitions of scans using the RNFL and macular analysis protocols of the Cirrus and Spectralis OCT instruments were performed. The differences between the two visits were analyzed by Student's t-test for paired samples. Repeatability of OCT measurements was evaluated by calculating the coefficients of variation for each of the parameters recorded and for each visit. RESULTS: RNFL thicknesses provided by Cirrus and Spectralis OCT and macular measurements provided by Cirrus OCT differed significantly between the two visits. Macular thicknesses provided by Spectralis OCT before and after surgery were not significantly different. OCT repeatability was better after surgery with lower coefficients of variation for scans performed after surgical removal of the cataract. CONCLUSIONS: The presence of cataracts affects RNFL and macular measurements performed with OCT in NIDDM patients without retinopathy. The repeatability of the images significantly improved after cataract phacoemulsification.

Influence of cataract surgery on optical coherence tomography and neurophysiology measurements in patients with retinitis pigmentosa.

PURPOSE: To evaluate the effect of uncomplicated cataract phacoemulsification on the measurements of visual evoked potentials (VEP), pattern electroretinogram (PERG), and macular and retinal nerve fiber layer (RNFL) using 2 spectral-domain optical coherence tomography (OCT) instruments, the Cirrus OCT (Carl Zeiss Meditech) and Spectralis OCT (Heidelberg Engineering), in patients with retinitis pigmentosa (RP), and to assess the reliability of the OCT measurements before and after cataract surgery. DESIGN: Observational cross-sectional study. METHODS: Thirty-five eyes of 35 patients with RP (20 men and 15 women, 45-66 years) who underwent cataract phacoemulsification were studied. At 1 month before and 1 month after surgery, visual acuity, VEP, PERG, and 3 repetitions of scans using the RNFL and macular analysis protocols of the Cirrus and Spectralis OCT instruments were performed. The differences in measurements between the 2 visits were analyzed. Repeatability of OCT measurements was evaluated by calculating the coefficients of variation. RESULTS: VEP amplitude, RNFL thicknesses provided by Cirrus and Spectralis, and macular measurements provided by Cirrus OCT differed between the 2 visits. VEP latency, PERG measurements, and macular thicknesses provided by the Spectralis OCT before surgery did not differ significantly from those after surgery. The OCT repeatability was better after surgery, with lower coefficients of variation for scans performed after surgical removal of the cataract. The nuclear, cortical, and posterior subcapsular types of cataracts did not show different repeatability. CONCLUSIONS: The presence of cataracts affects VEP amplitude, RNFL, and macular measurements performed with OCT in eyes with RP. Image repeatability significantly improves after cataract phacoemulsification.

Electrochemical determination of cocaine using screen-printed cytochrome P450 2B4 based biosensors.

This paper describes the development of screen-printed cytochrome P450 2B4 based biosensors, from the fabrication of the device using a single screen-printing technology to its characterization and application in the determination of cocaine street samples. Voltammetric measurements were first performed in order to study the electrochemical behavior of the enzyme trapped in the structure of the working electrode, as well as its interaction with one of its substrates, cocaine. Then, chronoamperometric measurements were carried out for the characterization of the biosensors. Calibration curves under optimum conditions of the experimental variables have been used for establishing the reproducibility (5.91%, n=5), the repeatability (10.45%, n=3) and the capability of detection (0.2mM, α=ß=0.05) of the described method in the calibration range from 0.2 to 1.2mM. Finally, the performance of the developed biosensors has been successfully probed by the analysis of the purity of cocaine street samples.

Screen-printed biosensor based on the inhibition of the acetylcholinesterase activity for the determination of codeine.

The current paper presents the chronoamperometric determination of codeine using screen-printed carbon electrodes that incorporate tetrathiafulvalene in the matrix of the working electrode, as mediator, and cross-linked acetylcholinesterase. Applying a potential of +250 mV, a 1mM solution of acetylthiocholine in electrolyte solution pH 7 gives an oxidation signal due to the dimerization of its metabolite after the reaction with the enzyme. This electrochemical signal is decreased by consecutive additions of a solution of codeine, which allows the performance of curves of calibration for the validation of this electrochemical method, giving a reproducibility of 3.31% (n=6) and a capability of detection of 20 µM. This type of inhibition has been studied by means of a Lineweaver-Burk plot. Additionally, the developed biosensor was used for the determination of the quantity of codeine in pharmaceutical commercial tablets and urine samples.

CYP450 biosensors based on screen-printed carbon electrodes for the determination of cocaine.

A new electrochemical method has been described and characterized for the determination of cocaine using screen-printed biosensors. The enzyme cytochrome P450 was covalently attached to screen-printed carbon electrodes. Experimental design methodology has been performed to optimize the pH and the applied potential, both variables that have an influence on the chronoamperometric determination of the drug. This method showed a reproducibility of 3.56% (n=4) related to the slopes of the calibration curves performed in the range from 19 up to 166nM. It has been probed the used of this kind of biosensors in the determination of cocaine in street samples, with an average capability of detection of 23.05±3.53nM (n=3, α=ß=0.05).