Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 25
Filter
Add more filters










Publication year range
1.
Int J Emerg Med ; 17(1): 73, 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38872111

ABSTRACT

BACKGROUND: The World Health Organization (WHO) reports that Asia and Africa have the highest Chronic Liver Disease (CLD) mortality rate. Cirrhosis, responsible for 22.2 fatalities per 100,000 people, is India's 10th most common cause of mortality. The increasing prevalence of chronic liver disease necessitates a study to identify predictive factors for patients who visit the emergency department. Identifying elements that enhance the predictive value of mortality in unstable patients with CLD complications is important in emergency departments. This study aims to determine Clinical and Laboratory Parameters as mortality predictors in adult chronic liver disease patients. METHODOLOGY: The study was conducted at the emergency department of a tertiary healthcare center in Northern India. Patients with chronic liver disease above 18 years of age who satisfied the inclusion criteria were clinically evaluated. Clinical and demographic details were collected, and data was analyzed. RESULTS: Two hundred thirty-six patients were enrolled. The mean age was 50.77 ± 14.26 years. 78.4% of the participants were men. Abdominal distension, affecting 59.7% of patients, was the most common presenting ailment, followed by melena and hematemesis, affecting 41.9% and 32.6%, respectively. The mean stay in the emergency department was 10.29 ± 8.10 h. Refractory septic shock, the leading cause of mortality, accounts for 69.2% of all deaths, alongside grade 4 hepatic encephalopathy and massive Upper Gastrointestinal (UGI) bleeding, as identified in our study. Factors such as altered mental sensorium, high respiratory rate, low SpO2, increased heart rate, low systolic blood pressure, low diastolic blood pressure, and low Glasgow Coma Scale (GCS) on Emergency Department (ED) arrival are significantly associated with mortality. CONCLUSIONS: Chronic liver disease, a prevalent condition in India, most commonly seen in middle aged men and lower socioeconomic groups. The parameters independently associated with mortality in our study were presence of altered mental sensorium, Glasgow coma scale, Child Pugh class and need for ICU admission. Understanding the presentation pattern, and mortality predictors can help ED physicians in managing acute events and follow-ups.

3.
ACS Omega ; 9(5): 5386-5394, 2024 Feb 06.
Article in English | MEDLINE | ID: mdl-38343948

ABSTRACT

The present study described the construction and the electrochemical futures of a novel inject-printed electrochemical sensor based on spinel ferrite-doped manganese oxide nanoparticles (FMnONPs) for the sensitive differential pulse voltammetric quantification of brimonidine (BRIM) in ophthalmic solutions. At the optimized electroanalytical parameters, calibration graphs were linear within the BRIM concentration range of 24-3512 ng mL-1 and recorded a detection limit value of 8.21 ng mL-1. Cyclic voltammograms recorded at different scan rates indicated an adsorption-reaction mechanism for the electrooxidation of BRIM at the electrode surface with the involvement of two electrons and one proton based on the oxidation of the five-membered ring nitrogen atom as recommended by the molecular orbital calculations. The enhanced performance of the introduced inkjet-printed sensors integrated with FMnONPs encourages their application for monitoring BRIM residues in ophthalmic solutions and biological fluids in the presence of BRIM degradation products and other interferents for diverse quality control applications.

4.
ACS Omega ; 9(1): 1562-1572, 2024 Jan 09.
Article in English | MEDLINE | ID: mdl-38222558

ABSTRACT

Thermochromic inks have proven to be a promising security encoding approach for making commercially available products less susceptible to forgery. However, thermochromic inks have been plagued with poor durability. Thus, self-healable hydrogels can be used as self-repair inks with better durability. Herein, we combined hybrid cellulose nanofibers (CNFs) and sodium alginate (SA) with anthocyanidin(Cy)-based Brassica oleracea L. var. capitata extract in the existence of mordant (ferrous sulfate) to create a self-healing ink for authentication. CNFs were used as a reinforcement agent to enhance the mechanical strength of the sodium alginate hydrogel. Both durability and thermal stability were ensured using self-healing inks. Red cabbage was used to extract Cy-based chromophore as an environmentally friendly spectroscopic probe for immobilization into SA. Using varying concentrations of anthocyanidin, self-healable composite hydrogels (Cy@SA) with thermochromic properties were provided. Using the CIE Lab color coordinate system, homogeneous purple (569 nm) films were printed onto a sheet surface. Upon heating from 25 to 70 °C, the purple color changed to red (433 nm). Transmission electron microscopy was applied to study anthocyanidin/mordant (Cy/M) nanoparticles (NPs). The properties of the applied prints were analyzed using several methods. Both the hydrogel and stamped sheets were tested for their mechanical and rheological characteristics, respectively. Research on the nanocomposite ink (Cy@SA) antibacterial properties and cytotoxicity was also conducted.

5.
Environ Technol ; : 1-20, 2023 Jun 01.
Article in English | MEDLINE | ID: mdl-37248830

ABSTRACT

In the current investigation, we have reported on the preparation of Na-Mordenite (MOR) modified by tryptophan (MOR-NH2) nanocomposite was synthesized and characterized using FT-IR, XRD, SEM, XPS, and BET that represented that the MOR-NH2 has high surface area 288 m2/g and pore volume 0.38 cm3/g. This composite represented high efficiency in removal of food dye Azorubine (E122) was 1043 mg/g. Study all the factors that affected on the adsorption such as pH, dose, salinity, E122 dye concentration as well as study the adsorption isotherm models that represented that was fitted to Langmuir. Moreover, study the effect of time according to it the adsorption process was fitted to Pseudo-second-order, and the effect of temperature that approved that the reaction was endothermic, spontaneous, and chemisorption process. The MOR-NH2 nanocomposite was tested and proven to effectively inhibit the growth of Escherichia coli ATCC® 25922™ and Staphylococcus aureus ATCC® 25923™ at low concentrations. To the best of our knowledge, this work is the first to report the usage of MOR-NH2 adsorbents for the removal of E122 dye in wastewater samples. The mechanism of interaction between MOR-NH2 and E122 dye was determining as it could be through Hydrogen bonding, pore filling, or through π-π interaction. This research offers a promising solution for purifying water sources that are contaminated with a variety of chemicals, microorganisms, and other contaminants.

6.
ACS Omega ; 8(19): 16956-16965, 2023 May 16.
Article in English | MEDLINE | ID: mdl-37214711

ABSTRACT

ß-Cyclodextrin (CD) is currently exploited for the implantation of lipophobic polymer dots (PDs) for antimicrobial and anticancer laborers. Moreover, the PDs were investigated to act as a chemo-sensor for metal detection. The data revealed that under basic conditions, photoluminescent PDs (5.1 nm) were successively clustered with a controllable size at 190 °C, whereas under acidic conditions, smaller-sized non-photoluminescent carbon nanoparticles (2.9 nm) were obtained. The fluorescence intensity of synthesized PDs under basic conditions was affected by pH, and such an intensity was significantly higher compared to that prepared under acidic conditions. The PDs were exploited as florescent detectors in estimation of Ag+ ions in aquatic streams. Treatment of Ag+ ion colloids with PDs resulted in fluorescence quenching attributing to the production of AgNPs that approved by spectral studies. The cell viability percent was estimated for Escherichia coli, Staphylococcus aureus, and Candida albicans after incubation with PDs implanted under basic conditions for 24 h. The cell mortality percent was estimated for breast cancer (MCF-7) after incubation with different concentrations of PDs that were implanted under acidic versus basic conditions to show that treatment of the tested cells with 1000 µg/mL PDs prepared under basic (IC50 232.5 µg/mL) and acidic (IC50 88.6 µg/mL) conditions resulted in cell mortality percentages of 70 and 90%, respectively.

7.
RSC Adv ; 13(10): 6466-6480, 2023 Feb 21.
Article in English | MEDLINE | ID: mdl-36860528

ABSTRACT

As their manufacturing and consumption have increased, pharmaceutical chemicals have increasingly been found in wastewater. It is necessary to look into more effective methods, including adsorption, because current therapies can't completely eliminate these micro contaminants. This investigation aims to assess the diclofenac sodium (DS) adsorption onto an Fe3O4@TAC@SA polymer in a static system. Through Box-Behnken design (BBD), system optimization was carried out, and the ideal conditions - adsorbent mass of 0.01 g and agitation speed of 200 rpm - were chosen. The adsorbent was created utilizing X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), allowing us to gain a comprehensive understanding of its properties. The analysis of the adsorption process revealed that the external mass transference was the primary rate-controlling step, and the Pseudo-Second-Order model demonstrated the best correlation to kinetic experimental results. An endothermic, spontaneous adsorption process took place. The removal capacity was 858 mg g-1, which is a respectable result when compared to other adsorbents that have been utilized in the past to remove DS. Ion exchange, π-π interactions, electrostatic pore filling and hydrogen bonding all play a role in the adsorption of DS on the Fe3O4@TAC@SA polymer. After careful examination of the adsorbent towards a true sample, it was determined to be highly efficient after three regenerative cycles.

8.
Environ Sci Pollut Res Int ; 30(22): 62676-62688, 2023 May.
Article in English | MEDLINE | ID: mdl-36947383

ABSTRACT

Simple and green strategy was described for the development of multifunctional polyester nanofibers (PNFs). Solution blow spinning (SBS) technology was applied to in situ immobilize nanocomposites of polyaniline (PANi) and silver nanoparticles (AgNPs) into plasma-treated polyester nanoscaled fibers prepared. The polyester nanofibers were prepared from recycled polyethylene terephthalate waste, which was exposed plasma-curing and a REDOX reaction in the presence of AgNO3, aniline, and CH3COONH4. Plasma-catalyzed oxidative polymerization of aniline to polyaniline together with a reductive process of Ag+ to silver nanoparticles led to their enduring insoluble dispersion into the surface of polyester nanofibers. By taking the advantage of the PANi oxidation, AgNPs were precipitated from an aqueous medium of AgNPs. The morphological properties were investigated by various analytical techniques. The polyester fiber diameter was determined in the range of 450-650 nm. In addition, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were utilized to examine AgNPs, demonstrating diameters of 4-20 nm. The plasma-uncured AgNPs/PANi immobilized nanofibrous film displayed weak absorption bands at 399 nm and 403 nm upon increasing the concentration of AgNPs. On the other hand, the plasma-cured AgNPs/PANi immobilized nanofibers displayed strong absorption bands at 526 nm and 568 nm upon increasing the concentration of AgNPs. The AgNP-induced antimicrobial performance and the PANi-induced electrically conductivity were explored. The prepared PNFs showed high UV protection.


Subject(s)
Metal Nanoparticles , Nanofibers , Silver/pharmacology , Polyethylene Terephthalates , Aniline Compounds , Oxidation-Reduction
9.
J Mol Recognit ; 36(6): e3013, 2023 06.
Article in English | MEDLINE | ID: mdl-36999889

ABSTRACT

This paper presents the expansion of an optical, chemical sensor that can rapidly and reliably detect, quantify, and remove Ni(II) ions in oil products and electroplating wastewater sources. The sensor is based on mesoporous silica nanospheres (MSNs) that have an extraordinary surface area, uniform surface morphology, and capacious porosity, making them an excellent substrate for the anchoring of the chromoionophoic probe,3'-{(1E,1' E)-[(4-chloro-1,2 phenylene)bis (azaneylylidene)]-bis(methaneylylidene)}bis(2-hydroxybenzoic acid) (CPAMHP). The CPAMHP probe is highly selective and sensitive to Ni(II), enabling it to be used in naked-eye colorimetric recognition of Ni(II) ions. The MSNs provide several accessible exhibited sites for uniform anchoring of CPAMHP probe molecules, making it a viable chemical sensor even with the use of naked-eye sensing. The surface characters and structural analysis of the MSNs and CPAMHP sensor samples were examined using various techniques. The CPAMHP probe-anchored MSNs exhibit a clear and vivid color shift from pale yellow to green upon exposure to various concentrations of Ni(II) ions, with a reaction time down to approximately 1 minute. Furthermore, the MSNs can serve as a base to retrieve extremely trace amounts of Ni(II) ions, making the CPAMHP sensor a dual-functional device. The calculated limit of recognition for Ni(II) ions using the fabricated CPAMHP sensor samples is 0.318 ppb (5.43 × 10-9 M). The results suggest that the proposed sensor is a promising tool for the sensitive and reliable detection of Ni(II) ions in petroleum products and for removing Ni(II) ions in electroplating wastewater; the data indicate an excellent removal of Ni (II) up to 96.8%, highlighting the high accuracy and precision of our CPAMHP sensor.


Subject(s)
Nanospheres , Petroleum , Silicon Dioxide/chemistry , Electroplating , Wastewater , Nanospheres/chemistry , Ions/chemistry , Petroleum/analysis
10.
Luminescence ; 38(5): 613-624, 2023 May.
Article in English | MEDLINE | ID: mdl-36929638

ABSTRACT

Novel thermochromic and vapochromic paper substrates were prepared via screen printing with anthocyanin extract in the presence of ferrous sulfate mordant, resulting in multi-stimuli responsive colorimetric paper sheets. Environmentally friendly anthocyanin extract was obtained from red-cabbage (Brassica oleracea var. capitata L.) to function as spectroscopic probe in coordination with ferrous sulfate mordant. Pink anthocyanin/resin nanocomposite films immobilized onto paper surface were developed by well-dispersion of anthocyanin extract as a colorimetric probe in a binding agent without agglomeration. As demonstrated by CIE colorimetric studies, the pink (λmax = 418 nm) film deposited onto paper surface turns greenish-yellow (λmax = 552 nm) upon heating from 25 to 75°C, demonstrating new thermochromic film for anti-counterfeiting applications. The thermochromic effects were investigated at different concentrations of the anthocyanin extract. Upon exposure to ammonia gas, the color of the anthocyanin-printed sheets changes rapidly from pink to greenish-yellow, and then immediately returns to pink after taking the gaseous ammonia stimulus away, demonstrating vapochromic effect. The current sensor strip showed a detection limit for ammonia gas in the range 50-300 ppm. Both thermochromism and vapochromism showed high reversibility without fatigue. In addition to studying the rheological properties of the prepared composites, the morphological and mechanical properties of the printed cellulose substrates were also studied.


Subject(s)
Ammonia , Anthocyanins , Anthocyanins/chemistry , Cellulose , Plant Extracts
11.
ACS Omega ; 8(5): 5042-5049, 2023 Feb 07.
Article in English | MEDLINE | ID: mdl-36777607

ABSTRACT

The present study introduced the construction and electroanalytical characterization of novel tirofiban (TIR) carbon paste voltammetric sensors integrated with copper oxide nanoparticles. The copper oxide nanostructure remarkably enhanced the oxidation of TIR molecules on the electrode surface with an irreversible anodic oxidation peak at about 1.18 V. The peak current values of the recorded differential pulse voltammograms were correlated to the TIR concentrations within a defined linear range from 0.060 to 7.41 µg mL-1 with an LOD value of 20.7 ng mL-1. Based on the electrochemical behavior of TIR at different scan rates and with the aid of the molecular orbital calculations performed on the TIR molecule, the electro-oxidation reaction was postulated to undergo through the oxidation of the five-membered-ring nitrogen atom with the transfer of one electron and one proton. Based on the reported selectivity and sensitivity of the proposed method, TIR was successfully determined in Aggrastat intravenous infusion and biological samples with mean average recoveries agreeable with the UV spectrophotometric method.

12.
RSC Adv ; 12(48): 30906-30920, 2022 Oct 27.
Article in English | MEDLINE | ID: mdl-36349031

ABSTRACT

Aizoon extract is used as an eco-friendly anti-corrosive material for stainless steel 430 (SS430) in a 2 M hydrochloric acid solution. Many strategies were utilized to estimate the mitigation efficacy such as mass reduction (MR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). The inhibition percentage (%I) increases by increasing the concentration of Aizoon and reaches 95.8% at 300 ppm and 298 K, while it lowers by raising the temperature, reaching 85.6% at 318 K. Tafel curves demonstrated that Aizoon extract is a mixed type inhibitor with an excellent ability to inhibit the cathodic reaction. Adsorption of the Aizoon extract on an SS430 surface is regulated by the Langmuir adsorption model. The value is is -20.9 kJ mol-1 at 298 K indicating that the adsorption is of mixed type affecting both cathodic and anodic reactions. Thermodynamic factors for adsorption and activation processes were estimated and discussed. The adsorption of Aizoon extract on the SS430 surface was tested utilizing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) techniques. The Nyquist curves confirmed that Aizoon extract prohibits the disintegration of SS430 in an acid medium without changing the dissolution reaction mechanism. The theoretical calculations showed that Aizoon extract is considered as an excellent corrosion inhibitor. The experimental data were supported by theoretical evaluations.

13.
Cureus ; 14(9): e29355, 2022 Sep.
Article in English | MEDLINE | ID: mdl-36284822

ABSTRACT

Thyrotoxic periodic paralysis (TPP) is an uncommon disorder characterized by acute onset of hypokalemia (serum potassium level less than 3.5 mmol/L) and paralysis secondary to thyrotoxicosis. Patients can present with TPP as the first clinical manifestation of thyrotoxicosis. In patients presenting with acute episodes, the presence of hypokalemia and elevated levels of thyroid hormones with low thyroid-stimulating hormone levels (less than 0.35 µIU/mL) are important diagnostic clues. We report one case of TPP in which the acute onset of paralysis was the first clinical presentation of underlying thyrotoxicosis. After treatment with propranolol and carbimazole, the patient became symptom-free and euthyroid.

14.
Indian J Dent Res ; 33(1): 94-99, 2022.
Article in English | MEDLINE | ID: mdl-35946253

ABSTRACT

Background: Many studies explained the importance of remineralisation of early carious lesions with various remineralising agents. In the present study, we incorporated the remineralising agents in a dentifrice, applied that in artificial enamel caries and evaluated their remineralising potential and compared the efficacy among the three. Aim: To evaluate and compare the remineralisation potential of a dentifrice containing bioactive glass, casein phosphopeptide-amorphous calcium phosphate and novel laboratory synthesised strontiumdoped nanohydroxyapatite paste in artificial enamel caries. Methods and Materials: 120 enamel specimens were divided into 4 groups of 30 specimens each, based on the type of dentifrice applied: GI - conventional toothpaste (control group), GII - calcium sodium phosphosilicate (Novamin), GIII - casein phosphopeptide-amorphous calcium phosphate (GC tooth mousse) and GIV- Novel strontiumdoped nanohydroxyapatite paste (SrnHAp paste). Specimens in all the groups were subjected to demineralisation, and calcium/phosphorous ratio was analysed followed by remineralisation and the mean calcium-phosphorus ratio was assessed using a scanning electron microscope and energy dispersing X-ray analysis. Statistical Analysis: Data were analysed using IBM SPSS Statistics for Windows Software, version 22 (IBM Corp., Armonk, NY, USA). Descriptive statistics were used to calculate the mean and standard deviation. Kruskal-Wallis, ANOVA and Mann-Whitney tests were used. The level of significance was set at 5%. Results and Conclusion: All except the control group showed a net increase in calcium and phosphorous values after application of the respective remineralising agents in respective groups. Inter-group comparison revealed that Group IV - SrnHAp paste yields higher net calcium and phosphorous values than other groups. Hence, novel SrnHAp can be considered as the material of choice in remineralising early enamel carious lesions.


Subject(s)
Dental Caries , Dentifrices , Calcium , Calcium Phosphates , Caseins/pharmacology , Caseins/therapeutic use , Fluorides , Humans , Phosphopeptides , Strontium/therapeutic use , Tooth Remineralization/methods
15.
RSC Adv ; 12(6): 3253-3273, 2022 Jan 24.
Article in English | MEDLINE | ID: mdl-35425349

ABSTRACT

In this work, three different types of surfactants, namely, dodecyl trimethyl ammonium chloride (DTAC, C12H25N (CH3)3Cl)-, octyl phenol poly(ethylene glycol ether) x (TX-100, C34H62O11 for x = 10) and dioctyl sodium sulfosuccinate (AOT-100, C20H37O7NaS) with corrosion restraint were utilized as corrosion inhibitors for 1037 CS in 0.5 M HCl. The protection efficacy (% IE) was indicated by weight loss and electrochemical measurements. Polarization curves showed that the investigated compounds are mixed-type inhibitors. The protection efficacy (% IE) increases with the increase in the surfactant concentration and reached 64.42-86.46% at 8 × 10-4 M and 30 °C. Adsorption of these utilized surfactants (DTAC, TX-100, and AOT) onto the CS surface concurred with the Langmuir adsorption isotherm. Impedance data revealed that by increasing the surfactant concentration, the charge transfer resistance (R ct) increases and vice versa for the capacitance of double layer (C dl). Surface morphological investigations such as scanning electron microscopy (SEM) combined with EDX and atomic force microscopy (AFM) were used to further investigate the inhibitors' protective abilities. Monte Carlo simulations showed the great interaction between the tested surfactants and the metal surface of the CS. The theoretical results (density functional theory, DFT) were in good agreement with experimental measurements. The restraint efficiencies of anionic, neutral, and cationic surfactants regarded a certain dating to HSAB precept and Fukui indices.

16.
Cureus ; 14(1): e21246, 2022 Jan.
Article in English | MEDLINE | ID: mdl-35178309

ABSTRACT

Coronavirus disease 2019 (COVID-19) predominantly affects the respiratory system with manifestations ranging from a mild upper respiratory tract infection to severe acute respiratory distress syndrome. Neurological manifestations of COVID-19 are mainly thrombotic manifestations affecting the nervous system; however, demyelinating manifestation has been less defined. Although some recent studies have described the association between COVID-19 and Guillain-Barré syndrome (GBS), the strength of association and features of GBS in this setting are not yet clear. Here, we report one adult case of COVID-19 infection presenting with acute GBS, which was not preceded by any other respiratory, gastrointestinal, or other systemic infections. We performed a literature search in Medline via PubMed using the keywords or MeSH terms "COVID-19" or "SARS-CoV-2" and "Guillain-Barré syndrome" and "AIDP" and "AMAN," "Miller-Fischer syndrome" or "MFS." We reviewed 99 case reports, 38 reviews, and two meta-analyses. Several published reports have described a possible association between GBS and COVID-19 infection.

17.
Sultan Qaboos Univ Med J ; 21(3): 408-415, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34522406

ABSTRACT

OBJECTIVES: This study aimed to estimate the prevalence of social media usage and Internet addiction among Oman Medical Specialty Board (OMSB) residents and to determine associations between Internet addiction, sociodemographic characteristics and symptoms of depression. METHODS: This cross-sectional study took place between January and March 2017. All 499 residents enrolled in OMSB training programmes during the 2016-2017 academic year were targeted. A self-administered questionnaire was distributed to collect information concerning sociodemographic characteristics. In addition, the Patient Health Questionnaire-9 and Internet Addiction Test were used to screen for depression and Internet addiction, respectively. RESULTS: A total of 399 residents participated in the study (response rate: 80%). Overall, 115 residents (28.8%) had varying degrees of depression and 149 (37.3%) were addicted to the Internet; moreover, among those addicted, 54 (36.2%) had depression. While no significant associations were observed between Internet addiction and sociodemographic characteristics, the association between Internet addiction and depression was statistically significant (P = 0.012). CONCLUSION: Internet addiction was clearly detected among many OMSB residents, with a significant association observed between Internet addiction and depression. Although a causal link between these two variables cannot be established as depression is multifactorial in origin, the disadvantages and harmful effects of excessive Internet and social media usage need to be addressed. Further research on the consequences of Internet addiction and its effect on quality of life and academic achievement is recommended.


Subject(s)
Behavior, Addictive , Internet Addiction Disorder , Behavior, Addictive/epidemiology , Cross-Sectional Studies , Depression/epidemiology , Depression/etiology , Humans , Quality of Life
19.
Angew Chem Int Ed Engl ; 59(13): 5235-5241, 2020 03 23.
Article in English | MEDLINE | ID: mdl-31944488

ABSTRACT

Stapled peptides are chemical entities in-between biologics and small molecules, which have proven to be the solution to high affinity protein-protein interaction antagonism, while keeping control over pharmacological performance such as stability and membrane penetration. We demonstrate that the multicomponent reaction-based stapling is an effective strategy for the development of α-helical peptides with highly potent dual antagonistic action of MDM2 and MDMX binding p53. Such a potent inhibitory activity of p53-MDM2/X interactions was assessed by fluorescence polarization, microscale thermophoresis, and 2D NMR, while several cocrystal structures with MDM2 were obtained. This MCR stapling protocol proved efficient and versatile in terms of diversity generation at the staple, as evidenced by the incorporation of both exo- and endo-cyclic hydrophobic moieties at the side chain cross-linkers. The interaction of the Ugi-staple fragments with the target protein was demonstrated by crystallography.


Subject(s)
Peptides/chemistry , Peptides/metabolism , Proto-Oncogene Proteins c-mdm2/chemistry , Tumor Suppressor Protein p53/chemistry , Aldehydes/chemistry , Amines/chemistry , Amino Acid Sequence , Catalytic Domain , Crystallography, X-Ray , Cyanides/chemistry , Fluorescence Polarization , Magnetic Resonance Spectroscopy , Models, Molecular , Protein Binding , Protein Conformation
20.
Cell ; 178(5): 1115-1131.e15, 2019 08 22.
Article in English | MEDLINE | ID: mdl-31442404

ABSTRACT

Little is known about how metabolites couple tissue-specific stem cell function with physiology. Here we show that, in the mammalian small intestine, the expression of Hmgcs2 (3-hydroxy-3-methylglutaryl-CoA synthetase 2), the gene encoding the rate-limiting enzyme in the production of ketone bodies, including beta-hydroxybutyrate (ßOHB), distinguishes self-renewing Lgr5+ stem cells (ISCs) from differentiated cell types. Hmgcs2 loss depletes ßOHB levels in Lgr5+ ISCs and skews their differentiation toward secretory cell fates, which can be rescued by exogenous ßOHB and class I histone deacetylase (HDAC) inhibitor treatment. Mechanistically, ßOHB acts by inhibiting HDACs to reinforce Notch signaling, instructing ISC self-renewal and lineage decisions. Notably, although a high-fat ketogenic diet elevates ISC function and post-injury regeneration through ßOHB-mediated Notch signaling, a glucose-supplemented diet has the opposite effects. These findings reveal how control of ßOHB-activated signaling in ISCs by diet helps to fine-tune stem cell adaptation in homeostasis and injury.


Subject(s)
Diet, High-Fat , Ketone Bodies/metabolism , Stem Cells/metabolism , 3-Hydroxybutyric Acid/blood , 3-Hydroxybutyric Acid/pharmacology , Aged, 80 and over , Animals , Cell Differentiation/drug effects , Cell Self Renewal , Female , Histone Deacetylase Inhibitors/pharmacology , Humans , Hydroxymethylglutaryl-CoA Synthase/deficiency , Hydroxymethylglutaryl-CoA Synthase/genetics , Hydroxymethylglutaryl-CoA Synthase/metabolism , Intestines/cytology , Intestines/pathology , Male , Mice , Mice, Knockout , Receptors, G-Protein-Coupled/metabolism , Receptors, Notch/metabolism , Signal Transduction/drug effects , Stem Cells/cytology , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...