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American Journal of Translational... 2022Constipation is a common gastrointestinal problem worldwide. Its impact on health can range from an unpleasant problem to being seriously troublesome. When lifestyle... (Review)
Review
Constipation is a common gastrointestinal problem worldwide. Its impact on health can range from an unpleasant problem to being seriously troublesome. When lifestyle modification fails to deal with constipation, laxatives are the mainstay of therapy. There are several types of laxatives currently available; however, there still remains a need for better laxatives because certain currently available laxatives are not appropriate for or accessible to some patients. Preclinical experiments to study the laxative potential of substances/products of interest are vital to improving that situation. The selection of appropriate experimental models for assessing the laxative activities of substances/products under investigation is crucial to achieving valid and meaningful results. This article provides a scoping review of the literature, outlining, and summarizing models currently being used in preclinical experiments assessing the laxative activities of substances/products under investigation. The review includes both screening models, e.g., the isolated organ bath system, fecal assessment and intestinal transit assay, and confirmation models, e.g., constipation models. Chemical substances/drugs used to induce constipation in constipation models, e.g., loperamide, diphenoxylate, montmorillonite, and clonidine, as well as standard laxative agents used as a positive control in experimental models, e.g., bisacodyl, carbachol, lactulose, sodium picosulfate, castor oil, phenolphthalein, and yohimbine, are described in detail. The purpose of this article is to assist researchers in the design and implementation of preclinical experimental models for assessing laxative activities of substances/products under investigation to achieve valid and meaningful preclinical results prior to experimentation in humans.
PubMed: 35273679
DOI: No ID Found -
Indian Journal of Ophthalmology Sep 2023This case series highlights the challenges in eye banking and the importance of a quality assurance program. Three cases triggered corrective and preventive actions...
This case series highlights the challenges in eye banking and the importance of a quality assurance program. Three cases triggered corrective and preventive actions (CAPAs) to improve the processes. Case 1 emphasized training to prevent retrieval failures. Case 2 stressed the need for blood samples and comprehensive documentation. In Case 3, mishandling led to policy revisions and staff training. CAPA involved identifying concerns, root cause analysis, action plans, implementation, checks, and closure. Errors can occur in man, machinery, process, and policies. Continuous CAPA ensures continuous quality improvement and safe corneal tissue transplantation, benefiting patients in need.
Topics: Humans; Eye Banks; Corneal Transplantation; Cornea; Dioctyl Sulfosuccinic Acid; Phenolphthalein
PubMed: 37602597
DOI: 10.4103/IJO.IJO_1994_23 -
Biotechnology For Biofuels Feb 2021Lytic polysaccharide monooxygenases (LPMOs) are important industrial enzymes known for their catalytic degradation of recalcitrant polymers such as cellulose or chitin....
BACKGROUND
Lytic polysaccharide monooxygenases (LPMOs) are important industrial enzymes known for their catalytic degradation of recalcitrant polymers such as cellulose or chitin. Their activity can be measured by lengthy HPLC methods, while high-throughput methods are less specific. A fast and specific LPMO assay would simplify screening for new or engineered LPMOs and accelerate biochemical characterization.
RESULTS
A novel LPMO activity assay was developed based on the production of the dye phenolphthalein (PHP) from its reduced counterpart (rPHP). The colour response of rPHP oxidisation catalysed by the cellulose-specific LPMO from Thermoascus aurantiacus (TaAA9A), was found to increase tenfold by adding dehydroascorbate (DHA) as a co-substrate. The assay using a combination of rPHP and DHA was tested on 12 different metallo-enzymes, but only the LPMOs catalysed this reaction. The assay was optimized for characterization of TaAA9A and showed a sensitivity of 15 nM after 30 min incubation. It followed apparent Michaelis-Menten kinetics with k = 0.09 s and K = 244 µM, and the assay was used to confirm stoichiometric copper-enzyme binding and enzyme unfolding at a temperature of approximately 60 °C. DHA, glutathione and fructose were found to enhance LPMO oxidation of rPHP and in the optimized assay conditions these co-substrates also enabled cellulose degradation.
CONCLUSIONS
This novel and specific LPMO assay can be carried out in a convenient microtiter plate format ready for high-throughput screening and enzyme characterization. DHA was the best co-substrate tested for oxidation of rPHP and this preference appears to be LPMO-specific. The identified co-substrates DHA and fructose are not normally considered as LPMO co-substrates but here they are shown to facilitate both oxidation of rPHP and degradation of cellulose. This is a rare example of a finding from a high-throughput assay that directly translate into enzyme activity on an insoluble substrate. The rPHP-based assay thus expands our understanding of LPMO catalysed reactions and has the potential to characterize LPMO activity in industrial settings, where usual co-substrates such as ascorbate and oxygen are depleted.
PubMed: 33640002
DOI: 10.1186/s13068-021-01902-4 -
Orthopadie (Heidelberg, Germany) Sep 2023More than almost any other implant, fully implantable intramedullary distraction nails have changed corrective and reconstructive bone surgery. Based on the fundamentals... (Review)
Review
More than almost any other implant, fully implantable intramedullary distraction nails have changed corrective and reconstructive bone surgery. Based on the fundamentals of callus distraction, these new apparatus developments with their novel planning strategies and minimally invasive surgical techniques have opened up a wide range of indications and made the treatment reproducible and safe. The prerequisite, however, is that standardized procedures are adhered to, which concern both the preparation for the surgery, the surgery itself and the subsequent distraction treatment. Treatment with fully implantable intramedullary distraction nails should be performed at specialized centers, so that the paradigm shift in corrective and reconstructive limb surgery, which is already recognizable, will open the door for further developments.
Topics: Nails; Internal Fixators; Fracture Fixation, Intramedullary; Prostheses and Implants; Bone Lengthening; Dioctyl Sulfosuccinic Acid; Phenolphthalein
PubMed: 37620678
DOI: 10.1007/s00132-023-04418-x -
Vaccine Jan 2023Amid the COVID-19 pandemic, the scientific community has been understandably eager to combat misinformation about issues such as vaccine safety. In highly polarized...
Amid the COVID-19 pandemic, the scientific community has been understandably eager to combat misinformation about issues such as vaccine safety. In highly polarized information environments, however, even well-intentioned messages have the potential to produce adverse effects. In this study, we connect different disciplinary strands of social science to derive and experimentally test the novel hypothesis that although particular efforts to debunk misinformation about mRNA vaccines will reduce relevant misperceptions about that technology, these correctives will harm attitudes toward other types of vaccines. We refer to this as the "collateral damage hypothesis." Our study specifically examines a corrective message stating that "mRNA vaccines do not contain live virus," and our results offer some support for our hypothesis, with the corrective triggering increased societal risk perceptions of live vaccines. We also find that the effect is, predictably, most evident among those whose vaccine acceptance is low. Building on the theoretical grounding we outline, we test a "damage control" adjustment to the corrective message and present evidence supporting that it mitigates the collateral damage.
Topics: Humans; Pandemics; COVID-19; Dioctyl Sulfosuccinic Acid; Drug-Related Side Effects and Adverse Reactions; Phenolphthalein; mRNA Vaccines; Communication
PubMed: 36682880
DOI: 10.1016/j.vaccine.2022.12.045 -
Sensors (Basel, Switzerland) Oct 2022In this work, a coulometer was developed from a digitally controlled galvanostat. A simple colorimeter based on a RGB LED was used as a light emitter coupled to light...
In this work, a coulometer was developed from a digitally controlled galvanostat. A simple colorimeter based on a RGB LED was used as a light emitter coupled to light detectors, while light dependent resistance (LDR) and photodiodes have been developed as endpoint detectors. Both hardware and software have been adapted from the original galvanostat design. Regarding the hardware, new electrical signal conditioners (filters and voltage dividers) were included to optimize the working system. The software was developed based on an open source Arduino UNO microcontroller. The different variables that control the titration process are managed by an add-in module for Excel data acquisition software that is freely available. A study of the possible variables that influence the titration process has been carried out. The system was tested with two classical coulometric titrations such as iodometry (thiosulfate, ascorbic acid) and acid/base (potassium acid phthalate as standard). The developed system is versatile as different endpoint color indicators can be employed (starch and phenolphthalein for the investigated reactions). Different experimental arrangements have been studied: the nature of the electrodes (Pt, Ag), type of cells (two separate compartments or a single compartment), and light detectors (LDR, photodiode). The influence of several experimental parameters (both electrical, light, and integration time) was studied and chosen to obtain the best performance of the complete system. Reproducibility results below 1% can be obtained under controlled conditions. In the case of acid/base titrations, the presence of atmospheric carbon dioxide was detected, whose interference was mainly affected by the stirring rate and the titration time.
Topics: Ascorbic Acid; Carbon Dioxide; Phenolphthaleins; Potassium; Reproducibility of Results; Starch; Thiosulfates
PubMed: 36236640
DOI: 10.3390/s22197541 -
Pharmaceutical Biology Dec 2023Linnaeus (Bombacaceae) is known as silk cotton tree, the flowers of which are used in many medicinal applications.
CONTEXT
Linnaeus (Bombacaceae) is known as silk cotton tree, the flowers of which are used in many medicinal applications.
OBJECTIVE
To investigate the therapeutic effect of flower aqueous extracts (BCE) against loperamide-induced constipation and characterize the chemical composition of BCE.
MATERIALS AND METHODS
Sixty male Kunming mice were divided into control (saline), model (10 mg/kg loperamide + saline), phenolphthalein (10 mg/kg loperamide + 10 mg/kg phenolphthalein) and different dosage of BCE (10 mg/kg loperamide + 40, 80 and 160 mg/kg BCE, respectively) groups, and received intragastric administrations for eight days. Faecal water content, number of faeces, first black-stool defecation time and gastrointestinal transit rates were evaluated. Various biochemical and molecular biomarkers were assessed in blood and colon. UPLC-ESI-QTOF-MS/MS was used to tentatively identify the composition of the BCE.
RESULTS
BCE treatment (160 mg/kg) could increase faecal water (15.75%), faeces number (11.65%), gastrointestinal transit rate (25.37%) and decrease first black-stool defecation time (24.04%). The BCE (80 mg/kg) increased the serum level of motilin (30.62%), gastrin (54.46%) and substance P (18.99%), and decreased somatostatin (19.47%). Additionally, the BCE (160 mg/kg) reduced the mucosal damage, restored colonic goblet cell function, down-regulated the protein expression of AQP (33.60%) and increased c-kit protein expression (11.63%). Twelve known compounds, including protocatechuic acid, chlorogenic acid and rutin, previously reported in were identified in the BCE.
DISCUSSION AND CONCLUSIONS
This study suggested that BCE is a promising agent for the treatment of constipation.
Topics: Mice; Animals; Loperamide; Bombax; Tandem Mass Spectrometry; Constipation; Flowers; Water; Phenolphthaleins
PubMed: 36582187
DOI: 10.1080/13880209.2022.2157841 -
Langmuir : the ACS Journal of Surfaces... Mar 2024Development of smart coatings incorporated with corrosion indicators that can warn of corrosion through signaling the alteration of pH or metal-ion concentration at the...
Development of smart coatings incorporated with corrosion indicators that can warn of corrosion through signaling the alteration of pH or metal-ion concentration at the corrosion site, and simultaneously mitigate further corrosion, stands out as a highly efficient and economical approach to address corrosion issues. In this context, the present work provides a comprehensive comparison on the effectiveness of thymol blue (TB) and phenolphthalein (PhPh) in both sensing and inhibiting corrosion on mild steel. While most of the works primarily focused on independently investigating the corrosion indication behavior of different active agents, our study intends to offer valuable insights through the comparative analysis of TB and PhPh in making well-informed decisions when selecting the most effective indicator for a given set of application scenarios. Initially, TB and PhPh were dissolved in a 3.5% NaCl solution, and their ability to indicate and inhibit corrosion on mild steel was verified through a drop test and an electrochemical study, respectively. An electrochemical study and a salt spray test were carried out to evaluate the corrosion sensing and inhibiting capabilities of the coating produced on a mild steel substrate by integrating TB and PhPh in the sol-gel matrix. The synergistic effect of TB and PhPh in sensing and inhibiting corrosion was also studied by combining TB and PhPh in the sol-gel matrix. It was found that TB-based coatings showed approximately 8 times better inhibiting performance (in terms of charge transfer resistance) when compared to PhPh-based coatings, while the PhPh-based coating was around 16 times more sensitive (with respect to concentration and time) in indicating corrosion when compared to TB-based coatings on a mild steel substrate. Nevertheless, the combination of TB and PhPh in a 1:3 ratio incorporated into the sol-gel coating exhibited increased sensitivity in detecting corrosion and showed improved corrosion inhibition on mild steel.
PubMed: 38439129
DOI: 10.1021/acs.langmuir.4c00269 -
Polymers Sep 2022As an alternative to traditional riveting and welding materials, high-temperature-resistant adhesives, with their unique advantages, have been widely used in aviation,...
As an alternative to traditional riveting and welding materials, high-temperature-resistant adhesives, with their unique advantages, have been widely used in aviation, aerospace, and other fields. Among them, polyimide (PI) adhesives have been one of the most studied species both from basic and practical application aspects. However, in the main applications of solvent-type PI adhesives, pinholes or bubbles often exist in the cured PI adhesive layers due to the solvent volatilization and dehydration reaction, which directly affect the adhesive performance. To address this issue, electrospun PI nanofibrous membranes (NFMs) were employed as solvent-free or solvent-less adhesives for stainless steel in the current work. To enhance the adhesion of PI adhesives to the metal substrates, phenolphthalein groups and flexible ether bonds were introduced into the main chain of PIs via the monomers of 4,4'-oxydiphthalic anhydride (ODPA) and 3,3-bis[4-(4-aminophenoxy)phenyl] phthalide (BAPPT). At the same time, the methylethynyl group was used as the end-capping component, and the crosslinking reaction of the alkynyl group at high temperature further increased the adhesive strength of the PI adhesives. Three kinds of methylethynyl-terminated PI (METI) NFMs with the set molecular weights of 5000, 10,000, and 20,000 g/mol were first prepared via the one-step high-temperature polycondensation procedure. Then, the PI NFMs were fabricated via the standard electrospinning procedure from the soluble METI solutions. The afforded METI NFMs showed excellent melt-flowing behaviors at high temperature. Incorporation of the methylethynyl end-capping achieved a crosslinking reaction at 280-310 °C for the NFMs, which was about 70 °C lower than those of the phenylacetylene end-capping counterparts. Using the METI NFMs as adhesive, stainless steel adherends were successfully bonded, and the single-lap shear strength (LSS) was higher than 20.0 MPa at both room temperature (25 °C) and high temperature (200 °C).
PubMed: 36236026
DOI: 10.3390/polym14194078 -
Polymers Aug 2022Over the years, many materials have been used to restore buildings, paintings, ceramics, and mosaic pieces exhibiting different types of dyes and colour hues. Recently,...
Over the years, many materials have been used to restore buildings, paintings, ceramics, and mosaic pieces exhibiting different types of dyes and colour hues. Recently, geopolymers have been used for restoration purposes owing to their high chemical and mechanical resistance. In this work, white metakaolin was used to obtain white geopolymers, cured at 25 and 40 °C, as bulk materials to be coloured with synthetic organic dyes, i.e., bromothymol blue, cresol red, phenolphthalein, and methyl orange. These dyes were added during the fresh paste preparation to obtain dyed geopolymeric solids. Ionic conductivity and pH measurement confirmed the chemical stability of the consolidated materials, while FT-IR analyses were used to follow the geopolymerisation occurrences at different ageing times (from 7 to 56 days). Finally, the colour hues and properties were assessed in the CIELAB colour space before and after immersion in water.
PubMed: 36015635
DOI: 10.3390/polym14163380