Managing sample introduction problems in hydrophilic interaction liquid chromatography.

Sample injection can cause serious problems in hydrophilic interaction liquid chromatography (HILIC) when the injection solvent has higher elution strength than the mobile phase (mp). It can lead to asymmetric peak shapes and poor efficiency. The problem can occur when the mp contains a high proportion of organic e.

Bibliometric Analysis and Visualization of Catholic Health Care Research: 1973-2019.

A multi-dimensional construct of Catholic health care is examined using a bibliometric analysis of 181 scientific studies from the Web of Science database. Medical ethics, religion, and health services research by 418 authors from 26 countries reveals developments in the Catholic health care domain since 1973. Using VOSviewer, we map keyword clusters to reveal the structure of research on Catholic health care that transcends religious and secular literatures.

imaging of hepatic neutrophil migration in severe alcoholic hepatitis with In-radiolabelled leucocytes.

The study's aim was to image severe alcoholic hepatitis (SAH) using In-labelled leucocytes with two objectives in mind: firstly for non-invasive diagnosis and secondly to provide a platform for experimental therapies aiming to inhibit intrahepatic neutrophil migration. In-leucocyte scintigraphy was performed 30 min and 24 h post-injection in 19 patients with SAH, 14 abstinent patients with alcohol-related cirrhosis and 11 normal controls. Eleven with SAH and seven with cirrhosis also had Tc-nanocolloid scintigraphy.

Electrochemical oxidation coupled with liquid chromatography and mass spectrometry to study the oxidative stability of active pharmaceutical ingredients in solution: A comparison of off-line and on-line approaches.

Stability studies of pharmaceutical drug products and pharmaceutical active substances are important to research and development in order to fully understand and maintain product quality and safety throughout its shelf-life. Oxidative forced degradation studies are among the different types of stability studies performed by the pharmaceutical industry in order to understand the intrinsic stability of drug molecules. We have been comparing the use of electrochemistry as an alternative oxidative forced degradation method to traditional forced degradation and accelerated stability studies.

The application of electrochemistry to pharmaceutical stability testing--comparison with in silico prediction and chemical forced degradation approaches.

The aim of this study was to evaluate the use of electrochemistry to generate oxidative degradation products of a model pharmaceutical compound. The compound was oxidized at different potentials using an electrochemical flow-cell fitted with a glassy carbon working electrode, a Pd/H2 reference electrode and a titanium auxiliary electrode. The oxidative products formed were identified and structurally characterized by LC-ESI-MS/MS using a high resolution Q-TOF mass spectrometer.

Phyllodes Tumor of the Breast With Malignant Melanoma Component: A Case Report.

Phyllodes tumors of the breast display a wide variation in histological appearance and are classified into benign, borderline, and malignant categories based on a combination of histological parameters. These tumors may include a malignant heterologous component that is believed to originate through a process of multidirectional differentiation from a cancer stem cell. In these cases, the tumor is classified as a malignant phyllodes tumor.

Ion-exchange and hydrophobic interactions affecting selectivity for neutral and charged solutes on three structurally similar agglomerated ion-exchange and mixed-mode stationary phases.

The nature and extent of mixed-mode retention mechanisms evident for three structurally related, agglomerated, particle-based stationary phases were evaluated. These three agglomerated phases were Thermo Fisher ScientificIon PacAS11-HC - strong anion exchange, Thermo Fisher Scientific IonPac CS10--strong cation-exchange PS-DVB, and the Thermo Fisher Scientific Acclaim Trinity P1silica-based substrate, which is commercially marketed as a mixed-mode stationary phase. All studied phases can exhibit zwitterionic and hydrophobic properties, which contribute to the retention of charged organic analytes.

Single column comprehensive analysis of pharmaceutical preparations using dual-injection mixed-mode (ion-exchange and reversed-phase) and hydrophilic interaction liquid chromatography.

The comprehensive separation and detection of hydrophobic and hydrophilic active pharmaceutical ingredients (APIs), their counter-ions (organic, inorganic) and excipients, using a single mixed-mode chromatographic column, and a dual injection approach is presented. Using a mixed-mode Thermo Fisher Acclaim Trinity P1 column, APIs, their counter-ions and possible degradants were first separated using a combination of anion-exchange, cation-exchange and hydrophobic interactions, using a mobile phase consisting of a dual organic modifier/salt concentration gradient. A complementary method was also developed using the same column for the separation of hydrophilic bulk excipients, using hydrophilic interaction liquid chromatography (HILIC) under high organic solvent mobile phase conditions.

Symptomatic sinus bradycardia after a treatment course of high-dose oral prednisone.

Background: High-dose corticosteroid therapy is used to treat several severe autoimmune diseases. Despite a common knowledge in the medical community of the adverse effects of chronic corticosteroid use, there is much less awareness of the affects that can occur after very high doses are administered in a relatively short period of time.

Objective: Our objective was to report on the outpatient-based practice of administering high-dose corticosteroids for autoimmune disease and the possible bradycardic response that can occur as a result.

Adult small bowel obstruction.

Background: Small bowel obstruction (SBO) is a clinical condition that is often initially diagnosed and managed in the emergency department (ED). The high rates of potential complications that are associated with an SBO make it essential for the emergency physician (EP) to make a timely and accurate diagnosis.

Objectives: The primary objective was to perform a systematic review and meta-analysis of the history, physical examination, and imaging modalities associated with the diagnosis of SBO.

Kinetic mechanism of human DNA ligase I reveals magnesium-dependent changes in the rate-limiting step that compromise ligation efficiency.

DNA ligase I (LIG1) catalyzes the ligation of single-strand breaks to complete DNA replication and repair. The energy of ATP is used to form a new phosphodiester bond in DNA via a reaction mechanism that involves three distinct chemical steps: enzyme adenylylation, adenylyl transfer to DNA, and nick sealing. We used steady state and pre-steady state kinetics to characterize the minimal mechanism for DNA ligation catalyzed by human LIG1.

Novel highly hydrophilic zwitterionic monolithic column for hydrophilic interaction chromatography.

A novel zwitterionic hydrophilic porous poly(SPV-co-MBA) monolithic column was prepared by thermal co-polymerisation of 1-(3-sulphopropyl)-4-vinylpyridinium-betaine (4-SPV) and N,N'-methylenebisacrylamide (MBA). An HILIC/RP dual separation mechanism was observed on this optimised poly(SPV-co-MBA) monolithic column and the composition of the mobile phase corresponding to the transition from the HILIC to the RP mode was around 30% ACN in water. Higher hydrophilicity was achieved on this novel monolithic column compared to the poly(N,N-dimethyl-N-methacryloxyethyl-N-(3-sulphopropyl)ammonium betaine-co-ethylene dimethacrylate) monolithic column.

Mixed-mode reversed-phase and ion-exchange monolithic columns for micro-HPLC.

This paper describes the fabrication of RP/ion-exchange mixed-mode monolithic materials for capillary LC. Following deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (gamma-MAPS), monoliths were formed by copolymerisation of pentaerythritol diacrylate monostearate (PEDAS), 2-sulphoethyl methacrylate (SEMA) with/without ethylene glycol dimethacrylate (EDMA) within 100 microm id capillaries. In order to investigate the porous properties of the monoliths prepared in our laboratory, mercury intrusion porosimetry, SEM and micro-HPLC were used to measure the monolithic structures.

Application of parallel gradient high performance liquid chromatography with ultra-violet, evaporative light scattering and electrospray mass spectrometric detection for the quantitative quality control of the compound file to support pharmaceutical discovery.

The success of drug discovery assays, using plate-based technologies, relies heavily on the quality of the substrates being tested. Sample purity, identity and concentration must be assured for a screening hit to be validated. Most major pharmaceutical companies maintain large liquid screening files with often in excess of one million stock solutions, typically dissolved in DMSO.

Hydrophilic interaction chromatography using methacrylate-based monolithic capillary column for the separation of polar analytes.

A porous zwitterionic monolith was prepared by thermal copolymerization of N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl)ammonium betaine and ethylene dimethacrylate inside a 100-mum-i.d. capillary.

Preparation and characterization of long alkyl chain methacrylate-based monolithic column for capillary chromatography.

This paper describes the fabrication of long alkyl chain methacrylate monolithic materials for using as stationary phases in capillary liquid chromatography. Following deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (gamma-MAPS), monoliths were formed by co-polymerisation of stearyl methacrylate (SMA) with ethylene glycol dimethacrylate (EDMA) in the presence of the initiator AIBN and a mixture of porogens including iso-amyl alcohol and 1,4-butanediol. The monoliths were prepared in 100 microm i.