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1.
IEEE Trans Biomed Eng ; PP2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38683704

ABSTRACT

OBJECTIVE: To study the safety and efficacy of algorithmically controlled electroporation (ACE) against spontaneous equine melanoma. METHODS: A custom temperature sensing coaxial electrode was paired with a high voltage pulse generation system with integrated temperature feedback controls. Computational modeling and ex vivo studies were conducted to evaluate the system's ability to achieve and maintain target temperatures. Twenty-five equine melanoma tumors were treated with a 2000V protocol consisting of a 2-5-2 waveform, 45ºC temperature set point, and integrated energized times of 0.005 s, 0.01 s, or 0.02 s (2500x, 5000x, and 10000x 2 µs pulses, respectively). Patients returned 20-50 days post treatment to determine the efficacy of the treatment. RESULTS: ACE temperature control algorithms successfully achieved and maintained target temperatures in a diverse population of spontaneous tumors with significant variation in tissue impedance. All treatments were completed successfully without and without adverse events. Complete response rates greater than 93% were achieved in all treatment groups. CONCLUSION: ACE is a safe and effective treatment for spontaneous equine melanoma. The temperature control algorithm enabled rapid delivery of electroporation treatments without prior knowledge of tissue electrical or thermal properties and could adjust to real time changes in tissue properties. SIGNIFICANCE: Real time temperature control in electroporation procedures enables treatments near critical structures where thermal damage is contraindicated. Unlike standard approaches, ACE protocols do not require extensive pretreatment planning or knowledge of tissue properties to determine an optimal energy delivery rate and they can account for changes in tissue state (e.g. perfusion) in real time to simultaneously minimize treatment time and potential for thermal damage.

2.
IEEE Trans Biomed Eng ; 71(5): 1511-1520, 2024 May.
Article in English | MEDLINE | ID: mdl-38145519

ABSTRACT

OBJECTIVE: This study sought to investigate a novel strategy using temperature-controlled delivery of nanosecond pulsed electric fields as an alternative to the 50-100 microsecond pulses used for irreversible electroporation. METHODS: INSPIRE treatments were carried out at two temperatures in 3D tumor models using doses between 0.001 s and 0.1 s. The resulting treatment zones were quantified using viability staining and lethal electric field intensities were determined numerically. Computational modeling was then used to determine parameters necessary for INSPIRE treatments to achieve equivalent treatment zones to clinical electroporation treatments and evaluate the potential for these treatments to induce deleterious thermal damage. RESULTS: Lethal thresholds between 1109 and 709 V/cm were found for nominal 0.01 s treatments with pulses between 350 ns and 2000 ns at physiological temperatures. Further increases in dose resulted in significant decreases in lethal thresholds. Given these experimental results, treatment zones comparable to clinical electroporation are possible by increasing the dose and voltage used with nanosecond duration pulses. Temperature-controlled simulations indicate minimal thermal cell death while achieving equivalent treatment volumes to clinical electroporation. CONCLUSION: Nanosecond electrical pulses can achieve comparable outcomes to traditional electroporation provided sufficient electrical doses or voltages are applied. The use of temperature-controlled delivery may minimize thermal damage during treatment. SIGNIFICANCE: Intense muscle stimulation and the need for cardiac gating have limited irreversible electroporation. Nanosecond pulses can alleviate these challenges, but traditionally have produced significantly smaller treatment zones. This study suggests that larger ablation volumes may be possible with the INSPIRE approach and that future in vivo studies are warranted.


Subject(s)
Electroporation , Humans , Electroporation/methods , Temperature , Computer Simulation , Models, Biological , Cell Line, Tumor , Neoplasms/therapy , Animals , Electrochemotherapy/methods , Treatment Outcome
3.
Chem Commun (Camb) ; 59(85): 12727-12730, 2023 Oct 24.
Article in English | MEDLINE | ID: mdl-37800404

ABSTRACT

A library of cyclometallated iridium(III) complexes with a strong H-bonding motif in their ancillary ligand was synthesized, characterized and their photophysical properties measured. Demonstrated herein is a general synthetic high yield procedure for these compounds. We ascribe these yields to the use of an intermediary primer ligand. This de novo strategy circumnavigates the standard synthetic issues of H-bond rich ligand precursors (self-aggregation and poor solubility in organic solvents).

4.
Entropy (Basel) ; 25(9)2023 Aug 31.
Article in English | MEDLINE | ID: mdl-37761581

ABSTRACT

In the literature on imprecise probability, little attention is paid to the fact that imprecise probabilities are precise on a set of events. We call these sets systems of precision. We show that, under mild assumptions, the system of precision of a lower and upper probability form a so-called (pre-)Dynkin system. Interestingly, there are several settings, ranging from machine learning on partial data over frequential probability theory to quantum probability theory and decision making under uncertainty, in which, a priori, the probabilities are only desired to be precise on a specific underlying set system. Here, (pre-)Dynkin systems have been adopted as systems of precision, too. We show that, under extendability conditions, those pre-Dynkin systems equipped with probabilities can be embedded into algebras of sets. Surprisingly, the extendability conditions elaborated in a strand of work in quantum probability are equivalent to coherence from the imprecise probability literature. On this basis, we spell out a lattice duality which relates systems of precision to credal sets of probabilities. We conclude the presentation with a generalization of the framework to expectation-type counterparts of imprecise probabilities. The analogue of pre-Dynkin systems turns out to be (sets of) linear subspaces in the space of bounded, real-valued functions. We introduce partial expectations, natural generalizations of probabilities defined on pre-Dynkin systems. Again, coherence and extendability are equivalent. A related but more general lattice duality preserves the relation between systems of precision and credal sets of probabilities.

6.
Molecules ; 28(14)2023 Jul 21.
Article in English | MEDLINE | ID: mdl-37513446

ABSTRACT

Species of the genus Kalanchoe have a long history of therapeutic use in ethnomedicine linked to their remarkable healing properties. Several species have chemical and anatomical similarities, often leading to confusion when they are used in folk medicine. This review aims to provide an overview and discussion of the reported traditional uses, botanical aspects, chemical constituents, and pharmacological potential of the Kalanchoe species. Published scientific materials were collected from the PubMed and SciFinder databases without restriction regarding the year of publication through April 2023. Ethnopharmacological knowledge suggests that these species have been used to treat infections, inflammation, injuries, and other disorders. Typically, all parts of the plant are used for medicinal purposes either as crude extract or juice. Botanical evaluation can clarify species differentiation and can enable correct identification and validation of the scientific data. Flavonoids are the most common classes of secondary metabolites identified from Kalanchoe species and can be correlated with some biological studies (antioxidant, anti-inflammatory, and antimicrobial potential). This review summarizes several topics related to the Kalanchoe genus, supporting future studies regarding other unexplored research areas. The need to conduct further studies to confirm the popular uses and biological activities of bioactive compounds is also highlighted.


Subject(s)
Crassulaceae , Kalanchoe , Plants, Medicinal , Phytotherapy , Phytochemicals/chemistry , Ethnopharmacology , Plant Extracts/chemistry
7.
Adv Emerg Nurs J ; 45(3): 240-247, 2023.
Article in English | MEDLINE | ID: mdl-37501277

ABSTRACT

The purpose of this quality improvement project is to assess and improve the quality of splint application in the emergency department (ED), as well as the splint application confidence level of the ED staff. Consistent and high-quality splint application is critical in fracture stabilization and prevention of further injury. Significantly high turnover and a lack of formal training of ED staff has led to poor splint application, and in some cases, patient injuries related to the splints themselves. These injuries include pain, edema, and skin complications (A. P. Carino, 2017). A random, Likert-based analysis was performed on 20 ED-applied splints. Once analysis was complete, training courses were implemented to improve splint application techniques. Using the same Likert-based tool, applications of 20 posttraining splints were analyzed. In addition, ED staff confidence levels were scored before and after the training courses. Overall, statistically significant improvement was achieved in splint application quality and staff confidence. Correct splint applications increased from 50% to 95% after the educational sessions. Staff confidence in splint application also increased, from 35% to 77.1%. Quality splint application affects all patients. The higher risk population is more likely to suffer the consequences of poor splint application. This project had a positive impact on the region's marginalized patient population. These patients have limited resources, including lack of transportation, financial limitations, and typically are at higher risk for complications due to comorbidities.


Subject(s)
Fractures, Bone , Splints , Humans , Emergency Service, Hospital , Pain , Quality Improvement
8.
J Nat Prod ; 85(6): 1449-1458, 2022 06 24.
Article in English | MEDLINE | ID: mdl-35622967

ABSTRACT

Aureobasidin A (abA) is a natural depsipeptide that inhibits inositol phosphorylceramide (IPC) synthases with significant broad-spectrum antifungal activity. abA is known to have two distinct conformations in solution corresponding to trans- and cis-proline (Pro) amide bond rotamers. While the trans-Pro conformation has been studied extensively, cis-Pro conformers have remained elusive. Conformational properties of cyclic peptides are known to strongly affect both potency and cell permeability, making a comprehensive characterization of abA conformation highly desirable. Here, we report a high-resolution 3D structure of the cis-Pro conformer of aureobasidin A elucidated for the first time using a recently developed NMR-driven computational approach. This approach utilizes ForceGen's advanced conformational sampling of cyclic peptides augmented by sparse distance and torsion angle constraints derived from NMR data. The obtained 3D conformational structure of cis-Pro abA has been validated using anisotropic residual dipolar coupling measurements. Support for the biological relevance of both the cis-Pro and trans-Pro abA configurations was obtained through molecular similarity experiments, which showed a significant 3D similarity between NMR-restrained abA conformational ensembles and another IPC synthase inhibitor, pleofungin A. Such ligand-based comparisons can further our understanding of the important steric and electrostatic characteristics of abA and can be utilized in the design of future therapeutics.


Subject(s)
Depsipeptides , Proline , Depsipeptides/pharmacology , Peptides, Cyclic/pharmacology , Proline/chemistry , Protein Conformation
9.
PLoS Biol ; 18(12): e3000954, 2020 12.
Article in English | MEDLINE | ID: mdl-33270638

ABSTRACT

Our understanding of the evolutionary history of primates is undergoing continual revision due to ongoing genome sequencing efforts. Bolstered by growing fossil evidence, these data have led to increased acceptance of once controversial hypotheses regarding phylogenetic relationships, hybridization and introgression, and the biogeographical history of primate groups. Among these findings is a pattern of recent introgression between species within all major primate groups examined to date, though little is known about introgression deeper in time. To address this and other phylogenetic questions, here, we present new reference genome assemblies for 3 Old World monkey (OWM) species: Colobus angolensis ssp. palliatus (the black and white colobus), Macaca nemestrina (southern pig-tailed macaque), and Mandrillus leucophaeus (the drill). We combine these data with 23 additional primate genomes to estimate both the species tree and individual gene trees using thousands of loci. While our species tree is largely consistent with previous phylogenetic hypotheses, the gene trees reveal high levels of genealogical discordance associated with multiple primate radiations. We use strongly asymmetric patterns of gene tree discordance around specific branches to identify multiple instances of introgression between ancestral primate lineages. In addition, we exploit recent fossil evidence to perform fossil-calibrated molecular dating analyses across the tree. Taken together, our genome-wide data help to resolve multiple contentious sets of relationships among primates, while also providing insight into the biological processes and technical artifacts that led to the disagreements in the first place.


Subject(s)
Genetic Introgression/genetics , Primates/genetics , Animals , Biological Evolution , Cercopithecidae/genetics , Computational Biology/methods , Databases, Genetic , Fossils , Gene Flow/genetics , Genome/genetics , Models, Genetic , Phylogeny , Sequence Analysis, DNA/methods
10.
CRISPR J ; 3(5): 332-349, 2020 10.
Article in English | MEDLINE | ID: mdl-33095048

ABSTRACT

In September 2020, a detailed report on Heritable Human Genome Editing was published. The report offers a translational pathway for the limited approval of germline editing under limited circumstances and assuming various criteria have been met. In this perspective, some three dozen experts from the fields of genome editing, medicine, bioethics, law, and related fields offer their candid reactions to the National Academies/Royal Society report, highlighting areas of support, omissions, disagreements, and priorities moving forward.


Subject(s)
Gene Editing/ethics , Genome, Human , Human Experimentation/ethics , Academies and Institutes , Germ Cells , Humans , Research Report , Societies
11.
Neuroscientist ; 26(5-6): 438-454, 2020.
Article in English | MEDLINE | ID: mdl-32281909

ABSTRACT

Because our beliefs regarding our individuality, autonomy, and personhood are intimately bound up with our brains, there is a public fascination with cerebral organoids, the "mini-brain," the "brain in a dish". At the same time, the ethical issues around organoids are only now being explored. What are the prospects of using human cerebral organoids to better understand, treat, or prevent dementia? Will human organoids represent an improvement on the current, less-than-satisfactory, animal models? When considering these questions, two major issues arise. One is the general challenge associated with using any stem cell-generated preparation for in vitro modelling (challenges amplified when using organoids compared with simpler cell culture systems). The other relates to complexities associated with defining and understanding what we mean by the term "dementia." We discuss 10 puzzles, issues, and stumbling blocks to watch for in the quest to model "dementia in a dish."


Subject(s)
Alzheimer Disease/pathology , Brain/pathology , Dementia/pathology , Induced Pluripotent Stem Cells/cytology , Organoids/cytology , Animals , Cell Differentiation/physiology , Dementia/physiopathology , Humans
12.
Nat Ecol Evol ; 4(5): 745-752, 2020 05.
Article in English | MEDLINE | ID: mdl-32203476

ABSTRACT

Resolving the strategies by which organisms compete for limited resources is key to understanding behavioural and social evolution. When competing for matings, males in many species allocate mating effort preferentially towards higher-quality females. How males balance this against avoiding competition with rival males, who should also prefer high-quality females, is poorly understood. Kin selection theory further complicates these dynamics: males should avoid competition with close relatives especially because of added, indirect fitness costs. However, whether between-male relatedness modulates the intensity of intrasexual competition is equivocal. Here, we develop and test an analytical model describing how males should optimally allocate their mating efforts in response to information about differences in female quality, competitor presence/absence and competitor relatedness. Using freely interacting groups of Trinidadian guppies (Poecilia reticulata), we show concordance between observed and predicted mating effort allocation across all combinations of these factors. Thus, male mating effort is sensitive to variation in female quality, competitor presence and competitor relatedness, which is consistent with a kin-selected strategy of male-male competition. The fit of our model's predictions demonstrates that males integrate assessments of female quality and competitive context in a quantitatively meaningful way, implicating a competitive strategy that has been fine-tuned to maximize inclusive fitness gains.


Subject(s)
Poecilia , Animals , Female , Male , Reproduction , Sexual Behavior, Animal
13.
Nat Commun ; 10(1): 4227, 2019 09 17.
Article in English | MEDLINE | ID: mdl-31530809

ABSTRACT

Studies of rodent models of Alzheimer's disease (AD) and of human tissues suggest that the retinal changes that occur in AD, including the accumulation of amyloid beta (Aß), may serve as surrogate markers of brain Aß levels. As Aß has a wavelength-dependent effect on light scatter, we investigate the potential for in vivo retinal hyperspectral imaging to serve as a biomarker of brain Aß. Significant differences in the retinal reflectance spectra are found between individuals with high Aß burden on brain PET imaging and mild cognitive impairment (n = 15), and age-matched PET-negative controls (n = 20). Retinal imaging scores are correlated with brain Aß loads. The findings are validated in an independent cohort, using a second hyperspectral camera. A similar spectral difference is found between control and 5xFAD transgenic mice that accumulate Aß in the brain and retina. These findings indicate that retinal hyperspectral imaging may predict brain Aß load.


Subject(s)
Alzheimer Disease/diagnostic imaging , Amyloid beta-Peptides/chemistry , Biomarkers/chemistry , Retina/diagnostic imaging , Tomography, Optical Coherence/methods , Aged , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Animals , Biomarkers/metabolism , Brain/diagnostic imaging , Brain/metabolism , Cohort Studies , Female , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Middle Aged , Positron-Emission Tomography , Retina/metabolism
14.
PLoS One ; 13(9): e0202436, 2018.
Article in English | MEDLINE | ID: mdl-30208056

ABSTRACT

Neovascularization is the pathological driver of blinding eye diseases such as retinopathy of prematurity, proliferative diabetic retinopathy, and wet age-related macular degeneration. The loss of vision resulting from these diseases significantly impacts the productivity and quality of life of patients, and represents a substantial burden on the health care system. Current standard of care includes biologics that target vascular endothelial growth factor (VEGF), a key mediator of neovascularization. While anti-VGEF therapies have been successful, up to 30% of patients are non-responsive. Therefore, there is a need for new therapeutic targets, and small molecule inhibitors of angiogenesis to complement existing treatments. Apelin and its receptor have recently been shown to play a key role in both developmental and pathological angiogenesis in the eye. Through a cell-based high-throughput screen, we identified 4-aminoquinoline antimalarial drugs as potent selective antagonists of APJ. The prototypical 4-aminoquinoline, amodiaquine was found to be a selective, non-competitive APJ antagonist that inhibited apelin signaling in a concentration-dependent manner. Additionally, amodiaquine suppressed both apelin-and VGEF-induced endothelial tube formation. Intravitreal amodaiquine significantly reduced choroidal neovascularization (CNV) lesion volume in the laser-induced CNV mouse model, and showed no signs of ocular toxicity at the highest doses tested. This work firmly establishes APJ as a novel, chemically tractable therapeutic target for the treatment of ocular neovascularization, and that amodiaquine is a potential candidate for repurposing and further toxicological, and pharmacokinetic evaluation in the clinic.


Subject(s)
Aminoquinolines/therapeutic use , Antimalarials/therapeutic use , Drug Repositioning , Retinal Neovascularization/drug therapy , Aminoquinolines/chemistry , Aminoquinolines/pharmacokinetics , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/pharmacology , Angiogenesis Inhibitors/therapeutic use , Animals , Antimalarials/chemistry , Antimalarials/pharmacokinetics , Apelin/metabolism , Apelin Receptors/antagonists & inhibitors , Apelin Receptors/metabolism , Cell Line , Cell Proliferation/drug effects , Choroidal Neovascularization/drug therapy , Choroidal Neovascularization/pathology , Disease Models, Animal , Female , Humans , Lasers , Mice , Mice, Inbred C57BL , Retinal Neovascularization/pathology , Small Molecule Libraries/chemistry , Small Molecule Libraries/therapeutic use , Tissue Distribution , Vascular Endothelial Growth Factor A/metabolism
15.
BMJ Paediatr Open ; 2(1): e000266, 2018.
Article in English | MEDLINE | ID: mdl-30094348

ABSTRACT

OBJECTIVE: To identify the degree to which parental diagnosis of depression or other long-term conditions, parental health-seeking behaviours and household factors were associated with a healthcare utilisation among children and young people (CYP) (0-15 years). DESIGN: Retrospective, cross-sectional study of electronic health records, from 25 252 patients registered at a large, London-based primary care provider. The associations between children's healthcare utilisation and the characteristics of the child, their parents/carers and their household structure were examined using multivariable regression. RESULTS: Controlling for parental utilisation, parental depression (vs not) was significantly associated with increased healthcare utilisation for CYP. Odds ratios for CYP with siblings=1.41 (95% CI 1.10 to 1.80) for emergency department (ED) attendances, 1.67 (95% CI 1.32 to 2.11) for outpatient appointments, 1.47 (95% CI 1.07 to 2.03) for inpatient admission, and rate rato=1.28 (95% CI 1.04 to 1.78) for general practitioner (GP) consultations.After adjusting for child and parental characteristics, parental general practice attendance (+1 from mean) was predictive of increased CYP general practice attendance, rate ratio 1.07 (95% CI 1.06 to 1.08) for CYP with siblings. Parental ED attendance also increased the risk of CYP ED attendance, with OR 1.27 (95% CI 1.12 to 1.44) for CYP with siblings. CONCLUSIONS: Parental depression is associated with increased utilisation of ED, outpatient and inpatient services by CYP, as well as with increased GP consultations among adolescents. Our results demonstrate that healthcare utilisation by CYP is associated with the health-seeking behaviour of adults in their household.

16.
BMJ Qual Saf ; 27(12): 989-999, 2018 12.
Article in English | MEDLINE | ID: mdl-30139822

ABSTRACT

OBJECTIVE: To quantify the association between patient self-management capability measured using the Patient Activation Measure (PAM) and healthcare utilisation across a whole health economy. RESULTS: 12 270 PAM questionnaires were returned from 9348 patients. In the adjusted analyses, compared with the least activated group, highly activated patients (level 4) had the lowest rate of contact with a general practitioner (rate ratio: 0.82, 95% CI 0.79 to 0.86), emergency department attendances (rate ratio: 0.68, 95% CI 0.60 to 0.78), emergency hospital admissions (rate ratio: 0.62, 95% CI 0.51 to 0.75) and outpatient attendances (rate ratio: 0.81, 95% CI 0.74 to 0.88). These patients also had the lowest relative rate (compared with the least activated) of 'did not attends' at the general practitioner (rate ratio: 0.77, 95% CI 0.68 to 0.87), 'did not attends' at hospital outpatient appointments (rate ratio: 0.72, 95% CI 0.61 to 0.86) and self-referred attendance at emergency departments for conditions classified as minor severity (rate ratio: 0.67, 95% CI 0.55 to 0.82), a significantly shorter average length of stay for overnight elective admissions (rate ratio 0.59, 95% CI 0.37 to 0.94),and a lower likelihood of 30- day emergency readmission (rate ratio: 0.68 , 95% CI 0.39 to 1.17), though this did not reach significance. CONCLUSIONS: Self-management capability is associated with lower healthcare utilisation and less wasteful use across primary and secondary care.


Subject(s)
Chronic Disease/therapy , Electronic Health Records/statistics & numerical data , Outcome Assessment, Health Care , Patient Acceptance of Health Care/statistics & numerical data , Patient Readmission/statistics & numerical data , Self-Management/methods , Adult , Cost Savings , Cross-Sectional Studies , Emergency Service, Hospital/statistics & numerical data , Female , Health Care Costs , Hospitalization/statistics & numerical data , Humans , Incidence , Length of Stay/economics , Male , Middle Aged , Primary Health Care/economics , Primary Health Care/statistics & numerical data , Retrospective Studies , Risk Assessment , Secondary Care/economics , Secondary Care/statistics & numerical data , Self-Management/statistics & numerical data , United States , Young Adult
17.
Oncotarget ; 9(12): 10388-10401, 2018 Feb 13.
Article in English | MEDLINE | ID: mdl-29535814

ABSTRACT

Parkinson's disease (PD) is the second most common neurodegenerative disorder and prevalence increases with age. Normal physiological changes that occur during the aging process reflect the pathological characteristics of Parkinson's disease. It is also recognized that age related changes significantly interact with the pathological mechanisms that underlie the neurodegeneration in PD and perpetuate the disease process. Despite the fact that aging is considered to be a primary risk factor for developing PD, the use of aged animal models are still under-utilized in pre-clinical research, thus reducing the translatability of experimental findings. Here, we use a natural compound astaxanthin (AXT) with multiple biological activities to attenuate neurotoxicity in a mouse model of Parkinson's disease in both young and aged mice. We observed that AXT preserved neurons in the substantia nigra of both young and aged mice that were exposed to the MPTP neurotoxin. However, AXT was less efficacious in the aged animals, as AXT was not able to protect against the MPTP induced loss of tyrosine hydroxylase (TH) throughout the aged nigro-striatal circuit. This disparity in the neuroprotective effect of AXT suggests that aging is a critical factor to consider during the development of novel therapeutics for neurodegenerative diseases and should be more rigorously evaluated in preclinical models.

18.
Int J Pediatr Otorhinolaryngol ; 106: 64-67, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29447894

ABSTRACT

Cockayne Syndrome (CS) is a rare, autosomal recessive disorder characterized by a spectrum of phenotypic abnormalities, including progressive sensorineural hearing loss (SNHL) that involves both peripheral and central components. To date, a single series of CS patients undergoing cochlear implant (CI) placement has been reported; this study reports on additional previously unreported pediatric CI recipients. Subjective benefits were noted early after activation in both patients, and speech perception scores improved over time as well, varying from 42 to 70% (versus 0-12% previously). Thus, we report that cochlear implantation in pediatric patients with CS can be effective in the management of progressive SNHL.


Subject(s)
Cochlear Implantation/methods , Cockayne Syndrome/surgery , Hearing Loss, Sensorineural/surgery , Child , Cochlear Implants , Female , Humans , Magnetic Resonance Imaging , Male , Retrospective Studies , Tomography, X-Ray Computed , Treatment Outcome
19.
ACS Med Chem Lett ; 8(7): 726-731, 2017 Jul 13.
Article in English | MEDLINE | ID: mdl-28740606

ABSTRACT

ERK is the effector kinase of the RAS-RAF-MEK-ERK signaling cascade, which promotes cell transformation and malignancy in many cancers and is thus a major drug target in oncology. Kinase inhibitors targeting RAF or MEK are already used for the treatment of certain cancers, such as melanoma. Although the initial response to these drugs can be dramatic, development of drug resistance is a major challenge, even with combination therapies targeting both RAF and MEK. Importantly, most resistance mechanisms still rely on activation of the downstream effector kinase ERK, making it a promising target for drug development efforts. Here, we report the design and structural/functional characterization of a set of bivalent ERK inhibitors that combine a small molecule inhibitor that binds to the ATP-binding pocket with a peptide that selectively binds to an ERK protein interaction surface, the D-site recruitment site (DRS). Our studies show that the lead bivalent inhibitor, SBP3, has markedly improved potency compared to the small molecule inhibitor alone. Unexpectedly, we found that SBP3 also binds to several ERK-related kinases that contain a DRS, highlighting the importance of experimentally verifying the predicted specificity of bivalent inhibitors. However, SBP3 does not target any other kinases belonging to the same CMGC branch of the kinome. Additionally, our modular click chemistry inhibitor design facilitates the generation of different combinations of small molecule inhibitors with ERK-targeting peptides.

20.
J Alzheimers Dis ; 58(4): 1293-1302, 2017.
Article in English | MEDLINE | ID: mdl-28550258

ABSTRACT

BACKGROUND: The association between the apolipoprotein E (APOE) ɛ4 allele and high risk of developing Alzheimer's disease (AD) dementia before the age of 80 has been recognized for over 30 years. However, the timing and mode of action of APOE is not understood, nor has there been a detailed analysis of the effect of APOE genotype on memory, hippocampal volume, and amyloid-ß (Aß) levels in cognitively normal adults. OBJECTIVE: Examine the effect of APOE allelic genotype on the relationship between Aß levels, hippocampal volume, and memory in cognitively normal adults. METHODS: This is a cross-sectional study of 989 cognitively normal older adults enrolled in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study, all of whom underwent APOE genotyping and memory assessment. A subset of this group underwent PET neuroimaging for Aß (n = 585) and MRI for hippocampal volume (n = 303). RESULTS: APOEɛ4 homozygotes (ɛ4/ɛ4) showed significantly worse episodic memory and higher Aß levels than ɛ4 heterozygotes. The relationship between increasing Aß levels and worse episodic memory was significant for ɛ3 homozygotes (ɛ3/ɛ3), ɛ4 heterozygotes, and strongest for ɛ4 homozygotes. There were no differences in hippocampal volume between APOE groups; the relationship between smaller hippocampal volume and worse episodic memory was significant only for ɛ4 homozygotes. CONCLUSION: APOE acts in a co-dominant fashion on Aß levels, episodic memory, and hippocampal volume in cognitively normal older adults. APOEɛ4 is central to the events that lead to AD in cognitively normal older adults, likely through a quantitative role in the disruption of Aß clearance.


Subject(s)
Amyloid beta-Peptides/metabolism , Apolipoproteins E/genetics , Cognition/physiology , Hippocampus/metabolism , Memory/physiology , Aged , Aged, 80 and over , Analysis of Variance , Australia , Cross-Sectional Studies , Female , Genotype , Hippocampus/diagnostic imaging , Humans , Magnetic Resonance Imaging , Male , Memory, Episodic , Middle Aged , Neuropsychological Tests , Positron-Emission Tomography
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