Mitigating In-Column Artificial Modifications in High-Temperature LC-MS for Bottom-Up Proteomics and Quality Control of Protein Biopharmaceuticals.

Elevating the column temperature is an effective strategy for improving the chromatographic separation of peptides. However, high temperatures induce artificial modifications that compromise the quality of the peptide analysis. Here, we present a novel high-temperature LC-MS method that retains the benefits of a high column temperature while significantly reducing peptide modification and degradation during reversed-phase liquid chromatography.

Evaluating C stationary phases with a positively charged surface for proteomic LC-MS applications using mobile phase acidified with reduced formic acid concentration.

We have recently demonstrated the ability of a C stationary phase with a positively charged surface (PCS-C) to provide superior chromatographic separation of peptides using mobile phase acidified with a mere 0.01 % formic acid, significantly improving MS sensitivity. Here, we examined three columns packed with different PCS-C phases using the MS-favorable mobile phase acidified with low formic acid concentrations to establish the impact of separation performance and better MS sensitivity on peptide identifications.

Pilot clinical study to evaluate the efficacy of a professionally delivered high fluoride varnish on erosive tooth wear in an in-situ model.

Objectives: The aim for this pilot study was to investigate the effect of a sodium fluoride varnish on step height measured by a profilometer from human enamel worn by healthy volunteers with a novel in situ/ex vivo erosion design.

Method: Healthy volunteers aged 18-70 years wore a palatal splint containing 8 human enamel samples and underwent two 3-day treatment periods for 6 h a day with a varnish containing sodium fluoride at 22,600 ppm and the control with the same ingredients but without fluoride. Each splint contained 4 polished and 4 unpolished samples.

A stationary phase with a positively charged surface allows for minimizing formic acid concentration in the mobile phase, enhancing electrospray ionization in LC-MS proteomic experiments.

The default choice of mobile phase acidifier for bottom-up LC-MS proteomic analyses is 0.10% formic acid because of its decent acidity, decent ion pairing ability, and low suppression of electrospray ionization. In recent years, state-of-the-art columns have been designed specifically to provide efficient separation even when using an MS-friendly mobile phase of low ionic strength.

Easy, Robust, and Repeatable Online Acid Cleavage of Proteins in Mobile Phase for Fast Quantitative LC-MS Bottom-Up Protein Analysis─Application for Ricin Detection.

Sample preparation involving the cleavage of proteins into peptides is the first critical step for successful bottom-up proteomics and protein analyses. Time- and labor-intensiveness are among the bottlenecks of the commonly used methods for protein sample preparation. Here, we report a fast online method for postinjection acid cleavage of proteins directly in the mobile phase typically used for LC-MS analyses in proteomics.

The subsurface lesion in erosive tooth wear.

Objectives: This study compared the surface change on natural and polished enamel exposed to a joint mechanical and chemical wear regimen.

Methods: Human enamel samples were randomly assigned to natural (n = 30) or polished (n = 30) groups, subjected to erosion (n = 10, 0.3% citric acid, 5 min), abrasion (n = 10, 30 s), or a combination (n = 10).

Use of polyvinyl siloxane impressions to monitor sub-5-μm erosive tooth wear on unpolished enamel.

Statement Of Problem: Whether polyvinyl siloxane impressions are capable of reproducing 5-μm changes on natural freeform enamel and potentially enabling clinical measurements of early surface changes consistent with wear of teeth or materials is unclear.

Purpose: The purpose of this in vitro study was to investigate and compare polyvinyl siloxane replicas with direct measurements of sub-5-μm lesions on unpolished human enamel lesions by using profilometry, superimposition, and a surface subtraction software program.

Material And Methods: Twenty ethically approved unpolished human enamel specimens were randomized to a previously reported cyclic erosion (n=10) and erosion and abrasion (n=10) model to create discrete sub-5-μm lesions on the surface.

Reversed-Phase Liquid Chromatography of Peptides for Bottom-Up Proteomics: A Tutorial.

The performance of the current bottom-up liquid chromatography hyphenated with mass spectrometry (LC-MS) analyses has undoubtedly been fueled by spectacular progress in mass spectrometry. It is thus not surprising that the MS instrument attracts the most attention during LC-MS method development, whereas optimizing conditions for peptide separation using reversed-phase liquid chromatography (RPLC) remains somewhat in its shadow. Consequently, the wisdom of the fundaments of chromatography is slowly vanishing from some laboratories.

The early wear susceptibility of cementum, enamel and dentine in vitro.

Objectives: To assess the differential early wear susceptibility of cementum, enamel and dentine at a micron level.

Methods: Whole human molar buccal surfaces incorporating natural enamel and cementum (n = 20) confirmed by imaging (digital microscopy: Keyence, VHX-7000 Milton Keynes, UK), were mounted, scanned (profilometry: XYRIS 4000, Taicaan, Southampton, UK), and allocated to receive erosion (citric acid, pH 2.7, 30 min (n = 10)) or erosion/abrasion challenges (3 cycles of (citric acid, pH 2.

V-set domain containing T-cell activation inhibitor-1 (VTCN1): A potential target for the treatment of autoimmune diseases.

Autoimmunity eventuates when the immune system attacks self-molecules as a result of the breakdown in immune tolerance. Targeting autoimmune diseases via immunomodulation has become an essential strategy in today's era. A B7 superfamily member immune checkpoint, the V-set domain containing T-cell activation inhibitor-1 (VTCN1), also known as B7-H4, B7S1, and B7x, is involved in negatively regulating T-cell activation.

Computational Investigations of AntiViral Lignan Derivatives as Potent Inhibitors of SARS CoV-2.

Due to alarming outbreak of pandemic COVID-19 in recent times, there is a strong need to discover and identify new antiviral agents acting against SARS CoV-2. Among natural products, lignan derivatives have been found effective against several viral strains including SARS CoV-2. Total of twenty-seven reported antiviral lignan derivatives of plant origin have been selected for computational studies to identify the potent inhibitors of SARS CoV-2.

Altered Levels of Negative Costimulatory Molecule V-Set Domain-Containing T-Cell Activation Inhibitor-1 (VTCN1) and Metalloprotease Nardilysin (NRD1) are Associated with Generalized Active Vitiligo.

Background: Vitiligo is characterized by depigmented macules on the skin caused due to autoimmune destruction of melanocytes. V-set domain-containing -cell activation inhibitor-1 (VTCN1) is a negative costimulatory molecule that plays a vital role in suppressing autoimmunity and tuning immune response. Nardilysin (NRD1), a metalloproteinase, cleaves membrane-tethered VTCN1 resulting in the shedding of soluble-VTCN1 (sVTCN1).

Autoantigen Discovery in the Hair Loss Disorder, Alopecia Areata: Implication of Post-Translational Modifications.

Alopecia areata (AA) is a chronic, multifactorial, polygenic, and heterogeneous disorder affecting growing hair follicles in susceptible individuals, which results in a non-scarring and reversible hair loss with a highly unpredictable course. Despite very considerable research effort, the nature of the precipitating factor(s) responsible for initiating AA in any given hair follicle remains unclear, due largely to significant gaps in our knowledge of the precise sequence of the etiopathogenic events in this dermatosis. However, disease-related changes in the immune-competence of the lower growing hair follicle, together with an active immune response (humoral and cellular) to hair follicle-associated antigens, are key associated phenomena.

Elevated X-Box Binding Protein1 Splicing and Interleukin-17A Expression Are Associated With Active Generalized Vitiligo in Gujarat Population.

Vitiligo is an autoimmune skin disorder defined by the destruction of functional epidermal melanocytes. It is a multifactorial and polygenic disorder caused due to oxidative stress, endoplasmic reticulum (ER) stress, and autoimmunity, among other factors. In the present study, we aimed to investigate the association of X-box Binding Protein 1 (XBP1) and Interleukin-17A (IL-17A) polymorphisms and monitor their systemic as well as skin expression levels in vitiligo patients from Gujarat population in India.

Active bleeding from downhill varices: case report and management.

Video 1EGD revealing 1 column of nonbleeding grade 2 varices in the middle third of the esophagus at the anterior wall; absent red wale sign and 3 columns of nonbleeding grade 3 varices in the upper third of the esophagus in the anterior and posterior wall. Stigmata of recent bleeding evident, red wale signs present, and 1 white nipple sign identified in the anterior wall, in the same column coming from the middle esophagus. Successful variceal banding ligation was performed, and there was no recurrence of bleeding.

Evaluation of strategies for overcoming trifluoroacetic acid ionization suppression resulted in single-column intact level, middle-up, and bottom-up reversed-phase LC-MS analyses of antibody biopharmaceuticals.

A wide range of strategies for efficient chromatography and high MS sensitivity in reversed-phase LC-MS analysis of antibody biopharmaceuticals and their large derivates has been evaluated. They included replacing trifluoroacetic acid with alternative acidifiers, relevancy of elevated column temperature, use of dedicated stationary phases, and counteraction of the suppression effect of trifluoroacetic acid in electrospray ionization. At the column temperature of 60 °C, which significantly reduces in-column protein degradation, the BioResolve RP mAb Polyphenyl, BioShell IgG C columns performed best using mobile phases with full or partial replacement of trifluoroacetic acid with difluoroacetic acid in the analysis of intact antibodies.

A Concise Review on the Role of Endoplasmic Reticulum Stress in the Development of Autoimmunity in Vitiligo Pathogenesis.

Vitiligo is characterized by circumscribed depigmented macules in the skin resulting due to the autoimmune destruction of melanocytes from the epidermis. Both humoral as well as cell-mediated autoimmune responses are involved in melanocyte destruction. Several studies including ours have established that oxidative stress is involved in vitiligo onset, while autoimmunity contributes to the disease progression.

Investigation of the Role of Interleukin 6 in Vitiligo Pathogenesis.

Unlabelled: Interleukin-6 (IL6) is involved in pathogenesis of several autoimmune disorders including vitiligo. Hence, we aimed to investigate the association of IL6 -174 G/C and -572 G/C polymorphisms and its transcript levels with vitiligo; to evaluate the effect of IL-6 on normal human melanocyte (NHM) viability and expression of IL6R, MITF and TYR. IL6 -174 G/C and -572 G/C polymorphisms were genotyped by ARMS-PCR and PCR-RFLP respectively in 343 controls and 322 vitiligo patients.

Phosphodiesterase 8B Polymorphism rs4704397 Is Associated with Infertility in Subclinical Hypothyroid Females: A Case-Control Study.

Background: Subclinical hypothyroidism (SCH) remains largely unnoticed as a major cause of infertility due to asymptomatic. Polymorphisms of phosphodiesterase 8B gene have been linked with various diseases, including female infertility. Hence, we aimed to study prevalence of SCH, in infertile females, explore association of rs4704397 A/G and rs6885099 G/A polymorphisms with infertility in females suffering from SCH and genotype-phenotype correlation of the polymorphisms with thyroid stimulating hormone (TSH) levels in Gujarat population.

Esophageal Bronchial Artery Fistulaization: A Complication of an Endobronchial Ultrasound.

Bronchial artery pseudoaneurysms are an extremely rare cause of upper gastrointestinal bleeding. The presence of a bronchial artery pseudoaneurysm resulting in an esophageal fistula is an entity that, to our knowledge, has yet to be described. Successful management requires an interdisciplinary approach to guide closure of the defects.

Publisher Correction: A genetic analysis identifies a haplotype at adiponectin locus: Association with obesity and type 2 diabetes.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Topiramate causing type II renal tubular acidosis: A case and review of the mechanism.

Topiramate has a wide array of pharmacologic effects, including proximal renal tubular acidosis (RTA). Clinicians must be wary of the possibility for development of somnolence due to compensatory hyperventilation and cardiac dysrhythmias.

A genetic analysis identifies a haplotype at adiponectin locus: Association with obesity and type 2 diabetes.

Adiponectin is a prime determinant of the status of insulin resistance. Association studies between adiponectin (ADIPOQ) gene single nucleotide polymorphisms (SNPs) and metabolic diseases have been reported earlier. However, results are ambiguous due to apparent contradictions.