Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 72
Filter
2.
J Cataract Refract Surg ; 50(1): 24-29, 2024 01 01.
Article in English | MEDLINE | ID: mdl-37702444

ABSTRACT

PURPOSE: To assess the performance of 4 intraocular lenses (IOLs) in various spherical aberration (SA) conditions, using the VAO adaptive optics simulator. SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas. DESIGN: Prospective case series. METHODS: Distance-corrected visual acuities at distance (CDVA), intermediate (DCIVA), and near (DCNVA) were measured in 42 dilated pseudophakic eyes at baseline and with ocular SA ranging from -0.4 to +0.4 µm in increments of 0.2 µm (6.0-mm pupil). 4 IOL types were assessed: monofocal IOLs with zero-SA, enhanced-monofocal, extended depth-of-focus (EDOF), and continuous range-of-vision. RESULTS: Compared with SA = 0 µm, significant changes (all P < .05) were: (1) zero-SA monofocal IOLs' DCNVA at high contrast improved by 0.13 logMAR with SA = -0.4 µm and worsened by 0.09 and 0.10 logMAR with SA = +0.2 and +0.4 µm, respectively. DCNVA at low contrast worsened by 0.09 logMAR with SA = +0.4 µm; and (2) with SA = -0.4 µm, the enhanced monofocal IOL lost 0.06 logMAR of CDVA at high contrast and gained 0.09 logMAR of DCNVA at low contrast. There were no significant changes from SA = 0 µm for EDOF and continuous range-of-vision IOLs. CONCLUSIONS: Zero-SA and EDOF IOLs were the most and least sensitive to SA modulation, respectively. In perfect optical systems where all the optical elements are aligned, induction of targeted amounts of negative SA improved the depth of focus of some IOL types. No benefit was found with positive SA.


Subject(s)
Lenses, Intraocular , Phacoemulsification , Humans , Lens Implantation, Intraocular , Prospective Studies , Visual Acuity , Prosthesis Design
3.
J Cataract Refract Surg ; 50(1): 7-11, 2024 01 01.
Article in English | MEDLINE | ID: mdl-37702522

ABSTRACT

PURPOSE: To compare the predictive accuracy of the biometer-embedded Barrett True-K TK and new total corneal power methods of intraocular lens (IOL) power calculation in eyes with prior laser vision correction (LVC) for myopia. SETTING: Academic clinical practice. DESIGN: Retrospective case series. METHODS: IOL power formulas were assessed using measurements from a swept-source optical coherence biometer. Refractive prediction errors were calculated for the Barrett True-K TK, EVO 2.0, Pearl-DGS, and HofferQST, which use both anterior and posterior corneal curvature measurements. These were compared with the Shammas, Haigis-L, Barrett True-K No History (NH), optical coherence tomography, and 4-formula average (AVG-4) on the ASCRS postrefractive calculator, and to the Holladay 1 and 2 with non linear axial length regressions (H1- and H2-NLR). RESULTS: The study comprised 85 eyes from 85 patients. Only the Barrett True-K TK and EVO 2.0 had mean numerical errors that were not significantly different from 0. The EVO 2.0, Barrett True-K TK, Pearl-DGS, AVG-4, H2-NLR, and Barrett True-K NH were selected for further pairwise analysis. The Barrett True-K TK and EVO 2.0 demonstrated smaller root-mean-square absolute error compared with the Pearl-DGS, and the Barrett True-K TK also had a smaller mean absolute error than the Pearl-DGS. CONCLUSIONS: The Barrett True-K TK and EVO 2.0 formulas had comparable performance to existing formulas in eyes with prior myopic LVC.


Subject(s)
Lenses, Intraocular , Myopia , Phacoemulsification , Humans , Lens Implantation, Intraocular , Refraction, Ocular , Retrospective Studies , Phacoemulsification/methods , Myopia/surgery , Optics and Photonics , Biometry/methods , Lasers
4.
Australas J Ageing ; 43(1): 100-111, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38160440

ABSTRACT

OBJECTIVE: Previous research on food, nutrition and dining practices in Australian residential aged care (RAC) homes has been based on a limited sample of single-home or multiple-home providers, but a nationwide study has not been conducted. The aim of this study was to provide a preliminary overview of current food, nutrition and dining practices across Australian RAC facilities using a nationwide survey. METHODS: A survey was distributed to Australian RAC homes in August-September 2020, as part of the National Congress on Food, Nutrition and the Dining Experience in Aged Care (February 2021). The survey, administered via an online portal, consisted of 38 semistructured questions including yes/no or multiple-choice responses, free text, frequency scales and number entry. Six key topics were explored, including 'food service system and environment', 'catering style', 'menu planning and evaluation', 'nutrition planning and requirements', 'nutrition-related screening and assessment' and 'training and additional information', which were informed by the Australian Government Department of Health and reflected the interests of the Congress. RESULTS: The final sample included 292 respondents (204 individual homes and 88 multiple-home proprietors) representing 1152 homes and 125,393 residents, encompassing approximately 43% of RAC homes (of a possible 2671) and 57% of residents (of a possible 219,965) in Australia. Survey respondents representing RAC homes included service managers, catering managers, Chief Executive Officers, cooks, chefs, dietitians or staff from other roles within homes. A number of potential areas of need were identified, included increasing the autonomy of residents to select the foods they desire, increasing the variety and choice (including timing) of meals, enhancing the dining environments in homes to stimulate food intake and increasing staff training and the number of trained chefs in homes, so that meals are prepared which address diverse nutritional needs of residents. CONCLUSIONS: This study provides insight into the food service and mealtime practices of over a third of Australian RAC homes. The findings of this survey may help to identify key targets for intervention to improve the food, nutrition and quality of life of aged care residents.


Subject(s)
Food Services , Quality of Life , Aged , Humans , Australia , Homes for the Aged , Nutritional Status , Surveys and Questionnaires , Meals
5.
Eur Arch Otorhinolaryngol ; 281(4): 2137-2143, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38117307

ABSTRACT

PURPOSE: To conduct a comparative performance evaluation of GPT-3.5, GPT-4 and Google Bard in self-assessment questions at the level of the American Sleep Medicine Certification Board Exam. METHODS: A total of 301 text-based single-best-answer multiple choice questions with four answer options each, across 10 categories, were included in the study and transcribed as inputs for GPT-3.5, GPT-4 and Google Bard. The first output responses generated were selected and matched for answer accuracy against the gold-standard answer provided by the American Academy of Sleep Medicine for each question. A global score of 80% and above is required by human sleep medicine specialists to pass each exam category. RESULTS: GPT-4 successfully achieved the pass mark of 80% or above in five of the 10 exam categories, including the Normal Sleep and Variants Self-Assessment Exam (2021), Circadian Rhythm Sleep-Wake Disorders Self-Assessment Exam (2021), Insomnia Self-Assessment Exam (2022), Parasomnias Self-Assessment Exam (2022) and the Sleep-Related Movements Self-Assessment Exam (2023). GPT-4 demonstrated superior performance in all exam categories and achieved a higher overall score of 68.1% when compared against both GPT-3.5 (46.8%) and Google Bard (45.5%), which was statistically significant (p value < 0.001). There was no significant difference in the overall score performance between GPT-3.5 and Google Bard. CONCLUSIONS: Otolaryngologists and sleep medicine physicians have a crucial role through agile and robust research to ensure the next generation AI chatbots are built safely and responsibly.


Subject(s)
Artificial Intelligence , Physicians , Humans , Search Engine , Certification , Sleep
6.
J Refract Surg ; 39(4): 242-248, 2023 Apr.
Article in English | MEDLINE | ID: mdl-37040215

ABSTRACT

PURPOSE: To assess the performance of multiple intraocular lens (IOL) formulas in eyes with keratoconus. METHODS: Eyes with stable keratoconus scheduled for cataract surgery with biometry measurements on the Lenstar LS900 (Haag-Streit) were included. Prediction errors were calculated using 11 different formulas, including two with keratoconus modifiers. Primary outcomes compared standard deviations, mean and median numerical errors, and percentage of eyes within diopter (D) ranges across all eyes with subgroup analysis according to anterior keratometric values. RESULTS: Sixty-eight eyes from 44 patients were identified. In eyes with keratometric values less than 50.00 D, prediction error standard deviations ranged from 0.680 to 0.857 D. Percentages of eyes within ±0.50 D of target ranged from 57.89% to 73.68% with no statistical differences among formulas. In eyes with a keratometric value of more than 50.00 D, prediction error standard deviations ranged from 1.849 to 2.349 D and were not statistically different with heteroscedastic analysis; percentages of eyes within ±0.50 D of target ranged from 0% to 18.18% with no statistical differences among formulas. Only keratoconus-specific formulas (Barrett-KC and Kane-KC) and the Wang-Koch axial length adjustment version of SRK/T resulted in median numerical errors not significantly different than 0, regardless of keratometric values. CONCLUSIONS: In keratoconic eyes, IOL formulas are less accurate than in normal eyes and result in hyperopic refractive outcomes that increase with steeper keratometric values. Using keratoconus-specific formulas and the Wang-Koch axial length adjustment version of SRK/T for axial lengths of 25.2 mm or greater improved IOL power prediction accuracy compared to other formulas. [J Refract Surg. 2023;39(4):242-248.].


Subject(s)
Cataract , Keratoconus , Lenses, Intraocular , Humans , Keratoconus/surgery , Lens Implantation, Intraocular , Retrospective Studies
7.
J Cataract Refract Surg ; 49(7): 697-703, 2023 07 01.
Article in English | MEDLINE | ID: mdl-36940190

ABSTRACT

PURPOSE: In short eyes, to compare the predictive accuracy of newer intraocular lens (IOL) power calculation formulas using traditional and segmented axial length (AL) measurements. SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas and East Valley Ophthalmology, Mesa, Arizona. DESIGN: Multi-center retrospective case series. METHODS: Measurements from an optical biometer were collected in eyes with AL <22 mm. IOL power calculations were performed with 15 formulas using 2 AL values: (1) machine-reported traditional AL (Td-AL) and (2) segmented AL calculated with the Cooke-modified AL nomogram (CMAL). 1 AL method and 7 formulas were selected for pairwise analysis of mean absolute error (MAE) and root mean square absolute error (RMSAE). RESULTS: The study comprised 278 eyes. Compared with the Td-AL, the CMAL produced hyperopic shifts without differences in RMSAE. The ZEISS AI IOL Calculator (ZEISS AI), K6, Kane, Hill-RBF, Pearl-DGS, EVO, and Barrett Universal II (Barrett) formulas with Td-AL were compared pairwise. The ZEISS AI demonstrated smaller MAE and RMSAE than the Barrett, Pearl-DGS, and Kane. K6 had a smaller RMSAE than the Barrett formula. In 73 eyes with shallow anterior chamber depth, the ZEISS AI and Kane had a smaller RMSAE than the Barrett. CONCLUSIONS: ZEISS AI outperformed Barrett, Pearl-DGS, and Kane. The K6 formula outperformed some formulas in selected parameters. Across all formulas, use of a segmented AL did not improve refractive predictions.


Subject(s)
Lenses, Intraocular , Phacoemulsification , Humans , Visual Acuity , Retrospective Studies , Artificial Intelligence , Biometry/methods , Refraction, Ocular , Axial Length, Eye , Optics and Photonics
8.
J Med Chem ; 65(21): 14261-14275, 2022 11 10.
Article in English | MEDLINE | ID: mdl-36282210

ABSTRACT

Hydrogen-bond donors are seen to cause more problems for drug designers than hydrogen-bond acceptors. Most of the polarity in drug-like compounds comes from hydrogen-bond acceptors since they typically exceed the hydrogen-bond donors in number and are more heavily solvated on an individual basis. The implications of this polarity imbalance for optimization of permeability and aqueous solubility are discussed. A factor that should be considered in optimization of ligand recognition by targets is that the presence of a hydrogen-bond donor generally implies that a hydrogen-bond acceptor is also present (but not vice versa). Frustrated solvation and secondary electrostatic interactions result from aligned hydrogen-bond donors and acceptors, and the design opportunities presented by these phenomena are discussed. Hydrogen-bond donors based on oxygen, nitrogen and carbon are compared as target recognition elements, and halogen- and chalcogen-bond donors are discussed as hydrogen-bond donor equivalents.


Subject(s)
Halogens , Hydrogen , Hydrogen Bonding , Static Electricity , Halogens/chemistry , Drug Design
9.
J Chem Inf Model ; 62(17): 4083-4094, 2022 09 12.
Article in English | MEDLINE | ID: mdl-36044342

ABSTRACT

We have used molecular dynamics (MD) simulations with hybrid quantum mechanics/molecular mechanics (QM/MM) potentials to investigate the reaction mechanism for covalent inhibition of cathepsin K and assess the reversibility of inhibition. The computed free energy profiles suggest that a nucleophilic attack by the catalytic cysteine on the inhibitor warhead and proton transfer from the catalytic histidine occur in a concerted manner. The results indicate that the reaction is more strongly exergonic for the alkyne-based inhibitors, which bind irreversibly to cathepsin K, than for the nitrile-based inhibitor odanacatib, which binds reversibly. Gas-phase energies were also calculated for the addition of methanethiol to structural prototypes for a number of warheads of interest in cysteine protease inhibitor design in order to assess electrophilicity. The approaches presented in this study are particularly applicable to assessment of novel warheads, and computed transition state geometries can be incorporated into molecular models for covalent docking.


Subject(s)
Cysteine Proteinase Inhibitors , Molecular Dynamics Simulation , Catalysis , Cathepsin K/metabolism , Cysteine Proteinase Inhibitors/chemistry , Protease Inhibitors , Quantum Theory
10.
Bioorg Med Chem ; 28(22): 115743, 2020 11 15.
Article in English | MEDLINE | ID: mdl-33038787

ABSTRACT

Leishmania mexicana is an obligate intracellular protozoan parasite that causes the cutaneous form of leishmaniasis affecting South America and Mexico. The cysteine protease LmCPB is essential for the virulence of the parasite and therefore, it is an appealing target for antiparasitic therapy. A library of nitrile-based cysteine protease inhibitors was screened against LmCPB to develop a treatment of cutaneous leishmaniasis. Several compounds are sufficiently high-affinity LmCPB inhibitors to serve both as starting points for drug discovery projects and as probes for target validation. A 1.4 Å X ray crystal structure, the first to be reported for LmCPB, was determined for the complex of this enzyme covalently bound to an azadipeptide nitrile ligand. Mapping the structure-activity relationships for LmCPB inhibition revealed superadditive effects for two pairs of structural transformations. Therefore, this work advances our understanding of azadipeptidyl and dipeptidyl nitrile structure-activity relationships for LmCPB structure-based inhibitor design. We also tested the same series of inhibitors on related cysteine proteases cathepsin L and Trypanosoma cruzi cruzain. The modulation of these mammalian and protozoan proteases represents a new framework for targeting papain-like cysteine proteases.


Subject(s)
Aza Compounds/pharmacology , Cathepsin B/antagonists & inhibitors , Cysteine Proteinase Inhibitors/pharmacology , Leishmania mexicana/drug effects , Trypanocidal Agents/pharmacology , Aza Compounds/chemical synthesis , Aza Compounds/chemistry , Cathepsin B/metabolism , Crystallography, X-Ray , Cysteine Endopeptidases/metabolism , Cysteine Proteinase Inhibitors/chemical synthesis , Cysteine Proteinase Inhibitors/chemistry , Dipeptides/chemical synthesis , Dipeptides/chemistry , Dipeptides/pharmacology , Dose-Response Relationship, Drug , Leishmania mexicana/enzymology , Molecular Dynamics Simulation , Molecular Structure , Nitriles/chemical synthesis , Nitriles/chemistry , Nitriles/pharmacology , Protozoan Proteins/antagonists & inhibitors , Protozoan Proteins/metabolism , Structure-Activity Relationship , Trypanocidal Agents/chemical synthesis , Trypanocidal Agents/chemistry
11.
Sex Med Rev ; 8(4): 518-530, 2020 10.
Article in English | MEDLINE | ID: mdl-32713674

ABSTRACT

INTRODUCTION: The 21st century has seen a series of viral pandemics that have collectively infected millions of individuals. To understand factors that may contribute to viral spread and address long-term health sequelae for survivors, it is important to review evidence regarding viral presence in semen, sexual transmission potential, and possible effects on fertility. AIM: To review the current literature regarding the sexual transmissibility of recent viral pandemics and their effects on semen parameters and fertility. We review evidence for the following viruses: Ebola, Zika, West Nile, pandemic influenza, severe acute respiratory syndrome (SARS), and SARS-corona virus-2 (SARS-CoV-2). METHODS: A literature search was conducted to identify relevant studies. Titles and abstracts were reviewed for relevance. References from identified articles were searched and included, if appropriate. MAIN OUTCOME MEASURES: The main outcome measure of this study was reviewing of peer-reviewed literature. RESULTS: Both the Ebola virus and Zika virus are present in semen, but only the Zika virus shows consistent evidence of sexual transmission. Current evidence does not support the presence of the West Nile virus, pandemic influenza, SARS, and SARS-CoV-2 in semen. The Zika virus appears to alter semen parameters in a way that diminishes fertility, but the effect is likely time limited. The West Nile virus and SARS have been associated with orchitis in a small number of case reports. Viruses that cause febrile illness, such as pandemic influenza, SARS, and SARS-CoV-2, are associated with decreased sperm count and motility and abnormal morphology. SARS and SARS-CoV-2 may interact with angiotensin-converting enzyme 2 receptors present in the testes, which could impact spermatogenesis. CONCLUSIONS: We have reported the presence in semen, sexual transmission potential, and fertility side effects of recent viral pandemics. Overall, semen studies and fertility effects are highly understudied in viral pandemics, and rigorous study on these topics should be undertaken as novel pandemics emerge. Payne K, Kenny P, Scovell JM, et al. Twenty-First Century Viral Pandemics: A Literature Review of Sexual Transmission and Fertility Implications for Men. Sex Med Rev 2020;8:518-530.


Subject(s)
Betacoronavirus , Coronavirus Infections/transmission , Infertility, Male/epidemiology , Infertility, Male/virology , Pneumonia, Viral/transmission , Sexually Transmitted Diseases, Viral/epidemiology , Sexually Transmitted Diseases, Viral/transmission , COVID-19 , Coronavirus Infections/epidemiology , Humans , Male , Pandemics , Pneumonia, Viral/epidemiology , SARS-CoV-2
12.
Bioorg Med Chem ; 27(22): 115083, 2019 11 15.
Article in English | MEDLINE | ID: mdl-31561938

ABSTRACT

The structure-activity relationship for nitrile-based cruzain inhibitors incorporating a P2 amide replacement based on trifluoroethylamine was explored by deconstruction of a published series of inhibitors. It was demonstrated that the P3 biphenyl substituent present in the published inhibitor structures could be truncated to phenyl with only a small loss of affinity. The effects of inverting the configuration of the P2 amide replacement and linking a benzyl substituent at P1 were observed to be strongly nonadditive. We show that plotting affinity against molecular size provides a means to visualize both the molecular size efficiency of structural transformations and the nonadditivity in the structure-activity relationship. We also show how the relationship between affinity and lipophilicity, measured by high-performance liquid chromatography with an immobilized artificial membrane stationary phase, may be used to normalize affinity with respect to lipophilicity.


Subject(s)
Amides/chemistry , Cysteine Endopeptidases/chemical synthesis , Protozoan Proteins/antagonists & inhibitors , Protozoan Proteins/chemical synthesis , Molecular Structure , Structure-Activity Relationship
13.
J Cheminform ; 11(1): 8, 2019 Jan 31.
Article in English | MEDLINE | ID: mdl-30706294

ABSTRACT

Ligand efficiency is a widely used design parameter in drug discovery. It is calculated by scaling affinity by molecular size and has a nontrivial dependency on the concentration unit used to express affinity that stems from the inability of the logarithm function to take dimensioned arguments. Consequently, perception of efficiency varies with the choice of concentration unit and it is argued that the ligand efficiency metric is not physically meaningful nor should it be considered to be a metric. The dependence of ligand efficiency on the concentration unit can be eliminated by defining efficiency in terms of sensitivity of affinity to molecular size and this is illustrated with reference to fragment-to-lead optimizations. Group efficiency and fit quality are also examined in detail from a physicochemical perspective. The importance of examining relationships between affinity and molecular size directly is stressed throughout this study and an alternative to ligand efficiency for normalization of affinity with respect to molecular size is presented.

14.
Eur Arch Otorhinolaryngol ; 275(7): 1697-1707, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29802464

ABSTRACT

OBJECTIVES: Systematic review of palate surgery for the treatment of OSA. METHODS: Independent searches to identify publications relevant to OSA treatment and upper airway palate surgery. All relevant studies published between January 2001 and February 2018 were included. Inclusion criteria were adult patients, documented airway evaluation methods and absent hypopharyngeal collapse. Outcomes included success rates of treatment, AHI, Epworth scale, QOL and snoring VAS. RESULTS: Fifty-nine papers with a total of 2715 patients, UPPP accounted for 16.7% of all the procedures. Evident differentiation progressing from 2001 to 2018, from 2001 to 2010, the percentage of UPPP procedures were 25.67%, from 2011 to 2018, there were only 12.6% of UPPP procedures. The average follow up was 8.18 months. Meta-analysis on the AHI change for all procedures, showed the fixed effect AHI per follow-up (FU) month change was 1.45 (95% CI 1.33, 1.8), p < 0.001; while for ESS, the fixed effect AHI per FU month change was 0.61 (95% CI 0.56, 0.66), p < 0.001. The mean decrease in AHI was from 35.66 to 13.91 (p < 0.001). The mean decrease in ESS was from 11.65 to 5.08 (p < 0.001). The mean AHI change was 19.9 (p < 0.001). The mean ESS change was 5.8 (p < 0.001). The overall pooled success rate was 67.5%. Meta-analysis of the procedures, showed that the respective mean AHI reduction was 24.7 for the anterior palatoplasty (p = 0.015), 19.8 for the lateral/expansion pharyngoplasty (p = 0.046), and 17.2 for the uvulopalatopharyngoplasty (p = 0.360). CONCLUSIONS: Better understanding of the upper airway and objective airway evaluation diagnostic techniques and innovative palate surgeries have improved success rates of OSA surgery.


Subject(s)
Palate/surgery , Sleep Apnea, Obstructive/surgery , Adult , Humans , Pharynx/surgery , Time Factors
15.
Biomaterials ; 162: 208-223, 2018 04.
Article in English | MEDLINE | ID: mdl-29459311

ABSTRACT

One reason for the lack of regeneration, and poor clinical outcomes, following central nervous system (CNS) injury is the formation of a glial scar that inhibits new axon growth. In addition to forming the glial scar, astrocytes have been shown to be important for spontaneous SCI recovery in rodents, suggesting some astrocyte populations are pro-regenerative, while others are inhibitory following injury. In this work, the effect of implanting hyaluronic acid (HA) hydrogels containing extracellular matrix (ECM) harvested from mouse embryonic stem cell (mESC)-derived astrocytes on histologic outcomes following SCI in rats was explored. In addition, the ability of HA hydrogels with and without ECM to support the transplantation of mESC-derived V2a interneurons was tested. The incorporation of ECM harvested from protoplasmic (grey matter) astrocytes, but not ECM harvested from fibrous (white matter) astrocytes, into hydrogels was found to reduce the size of the glial scar, increase axon penetration into the lesion, and reduce macrophage/microglia staining two weeks after implantation. HA hydrogels were also found to support transplantation of V2a interneurons and the presence of these cells caused an increase in neuronal processes both within the lesion and in the 500 µm surrounding the lesion. Overall, protoplasmic mESC-derived astrocyte ECM showed potential to treat CNS injury. In addition, ECM:HA hydrogels represent a novel scaffold with beneficial effects on histologic outcomes after SCI both with and without cells.


Subject(s)
Extracellular Matrix/chemistry , Hyaluronic Acid/chemistry , Hydrogels/chemistry , Spinal Cord Injuries/surgery , Animals , Astrocytes/drug effects , Embryonic Stem Cells/cytology , Embryonic Stem Cells/physiology , Interneurons/drug effects , Mice , Nerve Regeneration/drug effects , Rats , Tissue Engineering/methods
16.
J Pharm Biomed Anal ; 151: 186-193, 2018 Mar 20.
Article in English | MEDLINE | ID: mdl-29353807

ABSTRACT

A system using energy-dispersive X-ray diffraction (EDXRD) has been developed and tested using multivariate calibration for the quantitative analysis of tablet-form mixtures of common pharmaceutical ingredients. A principal advantage of EDXRD over the more traditional and common angular dispersive X-ray diffraction technique (ADXRD) is the potential of EDXRD to analyse tablets within their packaging, due to the higher energy X-rays used. In the experiment, a series of caffeine, paracetamol and microcrystalline cellulose mixtures were prepared and pressed into tablets. EDXRD profiles were recorded on each sample and a principal component analysis (PCA) was carried out in both unpackaged and packaged scenarios. In both cases the first two principal components explained >98% of the between-sample variance. The PCA projected the sample profiles into two dimensional principal component space in close accordance to their ternary mixture design, demonstrating the discriminating potential of the EDXRD system. A partial least squares regression (PLSR) model was built with the samples and was validated using leave-one-out cross-validation. Low prediction errors of between 2% and 4% for both unpackaged and packaged tablets were obtained for all three chemical compounds. The prediction capability through packaging demonstrates a truly non-destructive method for quantifying tablet composition and demonstrates good potential for EDXRD to be applied in the field of counterfeit medicine screening and pharmaceutical quality control.


Subject(s)
Counterfeit Drugs/analysis , Quality Control , Tablets/analysis , X-Ray Diffraction/methods , Calibration , Chemistry, Pharmaceutical/instrumentation , Chemistry, Pharmaceutical/methods , Chemistry, Pharmaceutical/organization & administration , Drug Packaging , Least-Squares Analysis , Principal Component Analysis , X-Ray Diffraction/instrumentation
17.
J Chem Inf Model ; 57(11): 2640-2645, 2017 11 27.
Article in English | MEDLINE | ID: mdl-29048168

ABSTRACT

A recent editorial (Aldrich et al. The Ecstasy and Agony of Assay Interference Compounds . J. Chem. Inf. MODEL: 2017 , 57 , 387 - 390 ) is examined critically. When assessing assay hits from screening, it is important to draw a distinction between false positives, that have no effect on target function, and compounds that affect target function through an undesirable mechanism of action. Observation of frequent-hitter behavior for a compound should be regarded as circumstantial evidence, rather than definitive proof, that the compound has interfered with assay readouts or acted through an undesirable mechanism of action. The applicability domain of published (Baell and Holloway J. Med. Chem. 2010 , 53 , 2719 - 2740 ) Pan Assay INterference compoundS (PAINS) filters is limited by the narrow scope of the proprietary data used to derive them. It is suggested that journal guidelines for authors should not prescribe, as those for the Journal of Medicinal Chemistry appear to do, that activity in assays reported for compounds that match PAINS filters be treated any differently from that for compounds that do not match PAINS filters. It is argued that use of models based on proprietary data in the evaluation of manuscripts would contradict the editorial policy of any journal that deemed the use of proprietary data to be unacceptable in modeling studies.


Subject(s)
Drug Discovery/methods , High-Throughput Screening Assays/methods , Data Interpretation, Statistical
18.
Bioorg Med Chem Lett ; 27(22): 5031-5035, 2017 11 15.
Article in English | MEDLINE | ID: mdl-29054358

ABSTRACT

The effects on potency of cruzain inhibition of replacing a nitrile group with alternative warheads were explored. The oxime was almost an order of magnitude more potent than the corresponding nitrile and has the potential to provide access to the prime side of the catalytic site. Dipeptide aldehydes and azadipeptide nitriles were found to be two orders of magnitude more potent cruzain inhibitors than the corresponding dipeptide nitriles although potency differences were modulated by substitution at P1 and P3. Replacement of the α methylene of a dipeptide aldehyde with cyclopropane led to a loss of potency of almost three orders of magnitude. The vinyl esters and amides that were characterized as reversible inhibitors were less potent than the corresponding nitrile by between one and two orders of magnitude.


Subject(s)
Cysteine Endopeptidases/metabolism , Cysteine Proteinase Inhibitors/chemistry , Catalytic Domain , Cathepsin L/chemistry , Cathepsin L/metabolism , Cysteine Endopeptidases/chemistry , Cysteine Proteinase Inhibitors/metabolism , Dipeptides/chemistry , Drug Design , Kinetics , Nitriles/chemistry , Structure-Activity Relationship
19.
Stem Cells Dev ; 26(22): 1597-1611, 2017 11 15.
Article in English | MEDLINE | ID: mdl-28851266

ABSTRACT

Central nervous system injury often leads to functional impairment due, in part, to the formation of an inhibitory glial scar following injury that contributes to poor regeneration. Astrocytes are the major cellular components of the glial scar, which has led to the belief that they are primarily inhibitory following injury. Recent work has challenged this by demonstrating that some astrocytes are required for spinal cord regeneration and astrocytic roles in recovery depend on their phenotype. In this work, two mixed populations containing primarily either fibrous or protoplasmic astrocytes were derived from mouse embryonic stem cells (mESCs). Motoneuron and V2a interneuron growth on live cultures, freeze-lysed cultures, or decellularized extracellular matrix (ECM) from astrocytes were assessed. Both neuronal populations were found to extend significantly longer neurites on protoplasmic-derived substrates than fibrous-derived substrates. Interestingly, neurons extended longer neurites on protoplasmic-derived ECM than fibrous-derived ECM. ECM proteins were compared with in vivo astrocyte expression profiles, and it was found that the ESC-derived ECMs were enriched for astrocyte-specific proteins. Further characterization revealed that protoplasmic ECM had significantly higher levels of axon growth promoting proteins, while fibrous ECM had significantly higher levels of proteins that inhibit axon growth. Supporting this observation, knockdown of spondin-1 improved neurite growth on fibrous ECM, while laminin α5 and γ1 knockdown decreased neurite growth on protoplasmic ECM. These methods allow for scalable production of specific astrocyte subtype-containing populations with different neuronal growth support capacities, and can be used for further studies of the functional importance of astrocyte heterogeneity.


Subject(s)
Astrocytes/cytology , Embryonic Stem Cells/cytology , Nerve Regeneration/physiology , Neurons/cytology , Animals , Extracellular Matrix/metabolism , Glial Fibrillary Acidic Protein/metabolism , Mice , Neurites/physiology , Neurogenesis/physiology , Neuroglia/cytology , Spinal Cord Injuries/metabolism , Spinal Cord Injuries/therapy
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 185: 234-244, 2017 Oct 05.
Article in English | MEDLINE | ID: mdl-28582725

ABSTRACT

The bioactivity of compounds is mainly dependent on molecular structure and the present work aims to explore the bonding features responsible for biological activity of novel anticancer drug N-(6-ferrocenyl-2-naphthoyl)-gamma-amino butyric acid ethyl ester (FNGABEE). In the present study, we investigate the molecular structural properties of newly synthesized title compound through experimental and quantum chemical studies. The detailed vibrational analysis has been performed using FT IR and FT Raman spectrum, aided by DFT computed geometry, vibrational spectrum, Eigen vector distribution and PED, at B3LYP/6-311++G(d,p) level. The resonance structure of naphthalene, different from that of benzene, revealed by molecular structure has been investigated using CC and CC stretching modes. The proton transfer in amide has been analyzed to obtain spectral distinction between different carbonyl and CN groups which point to the reactive sites responsible for binding with DNA and bovine serum albumin (BSA). The spectral distinction between eclipsed and staggered form of ferrocene has been analyzed. The molecular docking of FNGABEE with BSA and DNA has been performed to find the strength of binding and the moieties responsible for the interactions. The experimental binding studies of FNGABEE with BSA and DNA has been performed using UV absorption spectroscopy and fluorometric assay, to find the nature and strength of binding.


Subject(s)
Ferrous Compounds/chemistry , Ferrous Compounds/metabolism , Spectrum Analysis, Raman/methods , DNA/chemistry , DNA/metabolism , Molecular Docking Simulation , Protein Binding , Serum Albumin, Bovine/chemistry , Serum Albumin, Bovine/metabolism , Spectrometry, Fluorescence , Spectroscopy, Fourier Transform Infrared
SELECTION OF CITATIONS
SEARCH DETAIL
...