Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Epilepsy Behav ; 155: 109736, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38636146

RESUMO

Accurate seizure and epilepsy diagnosis remains a challenging task due to the complexity and variability of manifestations, which can lead to delayed or missed diagnosis. Machine learning (ML) and artificial intelligence (AI) is a rapidly developing field, with growing interest in integrating and applying these tools to aid clinicians facing diagnostic uncertainties. ML algorithms, particularly deep neural networks, are increasingly employed in interpreting electroencephalograms (EEG), neuroimaging, wearable data, and seizure videos. This review discusses the development and testing phases of AI/ML tools, emphasizing the importance of generalizability and interpretability in medical applications, and highlights recent publications that demonstrate the current and potential utility of AI to aid clinicians in diagnosing epilepsy. Current barriers of AI integration in patient care include dataset availability and heterogeneity, which limit studies' quality, interpretability, comparability, and generalizability. ML and AI offer substantial promise in improving the accuracy and efficiency of epilepsy diagnosis. The growing availability of diverse datasets, enhanced processing speed, and ongoing efforts to standardize reporting contribute to the evolving landscape of AI applications in clinical care.


Assuntos
Inteligência Artificial , Eletroencefalografia , Epilepsia , Aprendizado de Máquina , Convulsões , Humanos , Epilepsia/diagnóstico , Aprendizado de Máquina/tendências , Inteligência Artificial/tendências , Convulsões/diagnóstico , Convulsões/fisiopatologia , Eletroencefalografia/métodos
2.
J Am Chem Soc ; 145(36): 19932-19944, 2023 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-37642457

RESUMO

While the primary use of protein crystals has historically been in crystallographic structure determination, they have recently emerged as promising materials with many advantageous properties such as high porosity, biocompatibility, stability, structural and functional versatility, and genetic/chemical tailorability. Here, we report that the utility of protein crystals as functional materials can be further augmented through their spatial patterning and control of their morphologies. To this end, we took advantage of the chemically and kinetically controllable nature of ferritin self-assembly and constructed core-shell crystals with chemically distinct domains, tunable structural patterns, and morphologies. The spatial organization within ferritin crystals enabled the generation of patterned, multi-enzyme frameworks with cooperative catalytic behavior. We further exploited the differential growth kinetics of ferritin crystal facets to assemble Janus-type architectures with an anisotropic arrangement of chemically distinct domains. These examples represent a step toward using protein crystals as reaction vessels for complex multi-step reactions and broadening their utility as functional, solid-state materials. Our results demonstrate that morphology control and spatial patterning, which are key concepts in materials science and nanotechnology, can also be applied for engineering protein crystals.


Assuntos
Ferritinas , Porinas , Porosidade , Anisotropia , Catálise
3.
Chem Rev ; 121(22): 13701-13796, 2021 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-34405992

RESUMO

Proteins are nature's primary building blocks for the construction of sophisticated molecular machines and dynamic materials, ranging from protein complexes such as photosystem II and nitrogenase that drive biogeochemical cycles to cytoskeletal assemblies and muscle fibers for motion. Such natural systems have inspired extensive efforts in the rational design of artificial protein assemblies in the last two decades. As molecular building blocks, proteins are highly complex, in terms of both their three-dimensional structures and chemical compositions. To enable control over the self-assembly of such complex molecules, scientists have devised many creative strategies by combining tools and principles of experimental and computational biophysics, supramolecular chemistry, inorganic chemistry, materials science, and polymer chemistry, among others. Owing to these innovative strategies, what started as a purely structure-building exercise two decades ago has, in short order, led to artificial protein assemblies with unprecedented structures and functions and protein-based materials with unusual properties. Our goal in this review is to give an overview of this exciting and highly interdisciplinary area of research, first outlining the design strategies and tools that have been devised for controlling protein self-assembly, then describing the diverse structures of artificial protein assemblies, and finally highlighting the emergent properties and functions of these assemblies.


Assuntos
Ciência dos Materiais , Proteínas , Proteínas/química
4.
J Am Chem Soc ; 144(23): 10139-10144, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35666988

RESUMO

Crystalline materials are increasingly being used as platforms for encapsulating proteins to create stable, functional materials. However, the uptake efficiencies and stimuli-responsiveness of crystalline frameworks are limited by their rigidities. We have recently reported a new form of materials, polymer-integrated crystals (PIX), which combine the structural order of protein crystals with the dynamic, stimuli-responsive properties of synthetic polymers. Here we show that the crystallinity, flexibility, and chemical tunability of PIX can be exploited to encapsulate guest proteins with high loading efficiencies (up to 46% w/w). The electrostatic host-guest interactions enable reversible, pH-controlled uptake/release of guest proteins as well as the mutual stabilization of the host and the guest, thus creating a uniquely synergistic platform toward the development of functional biomaterials and the controlled delivery of biological macromolecules.


Assuntos
Materiais Biocompatíveis , Polímeros , Polímeros/química
5.
J Am Chem Soc ; 142(45): 19402-19410, 2020 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-33124805

RESUMO

The mechanical and functional properties of many crystalline materials depend on cooperative changes in lattice arrangements in response to external perturbations. However, the flexibility and adaptiveness of crystalline materials are limited. Additionally, the bottom-up, molecular-level design of crystals with desired dynamic and mechanical properties at the macroscopic level remains a considerable challenge. To address these challenges, we had previously integrated mesoporous, cubic ferritin crystals with hydrogel networks, resulting in hybrid materials (polymer-integrated crystals or PIX) which could undergo dramatic structural changes while maintaining crystalline periodicity and display efficient self-healing. The dynamics and mechanics of these ferritin-PIX were devoid of directionality, which is an important attribute of many molecular and macroscopic materials/devices. In this study, we report that such directionality can be achieved through the use of ferritin crystals with anisotropic symmetries (rhombohedral or trigonal), which enable the templated formation of patterned hydrogel networks in crystallo. The resulting PIX expand and contract anisotropically without losing crystallinity, undergo prompt bending motions in response to stimuli, and self-heal efficiently, capturing some of the essential features of sophisticated biological devices like skeletal muscles.

6.
J Am Chem Soc ; 139(28): 9691-9697, 2017 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-28650616

RESUMO

Azide-alkyne cycloaddition is a powerful reaction for the formation of bioconjugates. When catalyzed by Cu(I) or strain promotion, this cycloaddition is considered to be a "click" reaction with many applications in chemical biology and materials science. We report a new type of azide-alkyne click chemistry for the synthesis of protein conjugates using cucurbit[6]uril (CB6) supramolecular chemistry. CB6-promoted azide-alkyne cycloaddition has been previously used for the synthesis of rotaxanes but has not been applied to the development of complex bioconjugates. By developing new substrates for CB6 click that do not contain any cross-reactive functional groups and by optimizing reaction conditions, we converted CB6 click chemistry from a rotaxane synthesis tool into a useful bioconjugation technique. Using these new parameters, we synthesized a series of protein conjugates including protein-peptide, protein-DNA, protein-polymer, and protein-drug conjugates. We further demonstrated that CB6 click can be used in conjunction with strain-promoted azide-alkyne cycloaddition to generate distinct bioconjugates in protein mixtures. CB6 click is a promising new reaction for the development of protein conjugates and can be applied toward the synthesis of complex biomaterials for a wide range of applications.


Assuntos
Alcinos/química , Azidas/química , Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Proteínas/química , Química Click , Reação de Cicloadição , Modelos Moleculares , Estrutura Molecular , Proteínas/síntese química
7.
Bioconjug Chem ; 27(10): 2480-2485, 2016 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-27712069

RESUMO

Current approaches to nanoscale therapeutic delivery rely on the attachment of a drug of interest to a nanomaterial scaffold that is capable of releasing the drug selectively in a tumor environment. One class of nanocarriers receiving significant attention is protein nanomaterials, which are biodegradable and homogeneous in morphology and can be equipped with multiple functional handles for drug attachment. Although most protein-based nanocarriers are spherical in morphology, recent research has revealed that nonspherical nanomaterials may have favorable tumor uptake in comparison to their spherical counterparts. It is therefore important to expand the number of nonspherical protein-based nanocarriers that are available. Herein, we report the development of a self-assembling nanoscale disk derived from a double arginine mutant of recombinantly expressed tobacco mosaic virus coat protein (RR-TMV). RR-TMV disks display highly stable double-disk assembly states. These RR-TMV disks were functionalized with the chemotherapy drug doxorubicin (DOX) and further modified with polyethylene glycol (PEG) for improved solubility. RR-TMVDOX-PEG displayed cytotoxic properties similar to those of DOX alone when incubated with U87MG glioblastoma cells, but unmodified RR-TMV did not cause any cytotoxicity. The RR-TMV disk assembly represents a promising protein-based nanomaterial for applications in drug delivery.

8.
Am J Phys Med Rehabil ; 103(5): 390-394, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38112750

RESUMO

OBJECTIVE: The aim of the study is to evaluate the safety and efficacy of a physiatrist-led clinical pathway to expedite rehabilitation transitions for stroke patients with dysphagia requiring nasogastric tube or percutaneous endoscopic gastrostomy. DESIGN: This is a retrospective single-center observational study in 426 adults with stroke and dysphagia admitted to the acute hospital. Physican Medicine and Rehabilitation (PM&R) was consulted to determine dysphagia prognosis and candidacy for rehabilitation admission with nasogastric tube or percutaneous endoscopic gastrostomy. The proportion of patients accepted with nasogastric tube versus percutaneous endoscopic gastrostomy, progression to total oral diet during rehabilitation, and lengths of stay were tracked. RESULTS: The rate of recovery to total oral diet for patients accepted with nasogastric tube was 38/44 = 86.3% versus 29/75 = 38.6% with percutaneous endoscopic gastrostomy. There was a significant difference in mean time to total oral diet with nasogastric tube (20.37 days) versus percutaneous endoscopic gastrostomy (34.46 days): t (43) = 4.49, P < 0.001. The acute hospital length of stay was significantly shorter with nasogastric tube (12.9 days) versus percutaneous endoscopic gastrostomy (20.4 days): t (117) = 4.16, P < 0.001. Rehabilitation length of stay did not differ significantly between groups (26.9 vs. 32.0 days). CONCLUSION: Physiatrist-led initiatives to evaluate stroke patients with dysphagia can expedite rehabilitation transitions, prevent unnecessary invasive procedures, and reduce acute hospital length of stay.


Assuntos
Transtornos de Deglutição , Acidente Vascular Cerebral , Adulto , Humanos , Nutrição Enteral/métodos , Transtornos de Deglutição/etiologia , Transtornos de Deglutição/reabilitação , Procedimentos Clínicos , Gastrostomia/métodos , Estudos Retrospectivos , Acidente Vascular Cerebral/complicações , Intubação Gastrointestinal
9.
J Cataract Refract Surg ; 50(1): 64-71, 2024 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-37702514

RESUMO

PURPOSE: To compare the vault predictability of most available implantable collamer lens (ICL) sizing nomograms and identify which preoperative measurements are predictive of vault. SETTING: Private practice in Draper, Utah. DESIGN: Retrospective chart review. METHODS: This study was a retrospective analysis of 209 eyes of 106 patients who underwent STAAR Surgical ICL implantation. Analyses were performed based on the availability of preoperative parameters, varying the number of eyes for each test. Mean absolute error (MAE) of predicted vs actual postoperative vault was calculated for each nomogram. The frequency of Kim, Rocamora (least absolute shrinkage and selection operator-optical coherence tomography), Russo, and Reinstein recommending the correct ICL size in instances when Parkhurst, optimized white-to-white (WTW), and STAAR could not recommend a definitive ICL size was determined. Univariate and multivariate linear regression analysis was performed between preoperative measurements and vault. RESULTS: The Kim, Rocamora, Russo, and Reinstein nomograms had significantly lower MAE of predicted vs actual postoperative vault than the KSV2 and Nakamura V3 nomograms. The Russo formula most frequently recommended the correct ICL size when the Parkhurst, Optimized WTW, and STAAR nomograms could not provide ICL size recommendations. At the 0.05 significance level, anterior chamber depth (ACD), ciliary body inner diameter (CBID), and pupil diameter were the parameters found to have significant correlation with postoperative vault. CONCLUSIONS: The Kim, Rocamora, Russo, and Reinstein nomograms were the most predictive of vault. Additionally, ACD, CBID, and pupil diameter were found to be significantly correlated with vault and should be considered for use in future ICL sizing nomograms.


Assuntos
Miopia , Lentes Intraoculares Fácicas , Humanos , Nomogramas , Implante de Lente Intraocular/métodos , Estudos Retrospectivos , Miopia/cirurgia , Corpo Ciliar
10.
Burns ; 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38760187

RESUMO

BACKGROUND: Cyanide poisoning poses a significant threat to burn patients exposed to smoke in residential or workplace fires, leading to central nervous system dysfunction, hemodynamic instability, cardiovascular collapse, and death. Prompt administration of an effective antidote is critical. Hydroxocobalamin, a form of vitamin B12, is the gold standard treatment for cyanide toxicity, by binding to cyanide molecules and converting them into non-toxic cyanocobalamin that is eliminated by the kidneys. This mechanism is distinct from previous cyanide antidotes, which induce the formation of methemoglobin to bind to cyanide. Recent case studies have reported elevated methemoglobin levels after hydroxocobalamin administration, raising concerns regarding its safety. The current study investigates smoke inhalation patients treated with hydroxocobalamin at a single institution Burn Unit in hopes of enhancing our understanding of the complexities surrounding cyanide antidote therapy. METHODS: After Institutional Board Approval, a retrospective cohort study was conducted. Our sample comprised burn patients with inhalation injury admitted to a single institution from 2013 to 2023 and treated with hydroxocobalamin for suspected cyanide toxicity. We also analyzed a matched control cohort of similar patients with inhalation injury not treated with hydroxocobalamin. We analyzed changes and peaks in methemoglobin levels, lactate levels, blood urea nitrogen (BUN) and creatinine, ventilator days, % total body surface area (TBSA), various types of medications and dressings, and mortality. Statistical analyses included t-tests, chi-square, linear and logistic regressions, and correlation analysis. RESULTS: In the study, 36 patients with suspected inhalation injury were treated with hydroxocobalamin at the Los Angeles General (LAG) Burn Unit from 2013 to 2023, who were matched to 32 control patients with inhalation injury who were not treated with hydroxocobalamin. Demographic and baseline characteristics showed no statistically significant differences between the groups, including age, gender, BMI, and %TBSA. No significant differences were found in initial, final, peak, or change in methemoglobin levels. The study also revealed no significant disparities in initial lactate levels, mortality, kidney function tests, ventilator days, surgeries, or use of medications/treatments (e.g., Silvadene dressings, Vitamin C) between the two groups. When controlling for covariates, multiple linear regression analysis (age, gender, and %TBSA) indicated that hydroxocobalamin administration was not significantly associated with changes in methemoglobin or mortality. Increased %TBSA, however, was linked to elevated lactate levels. CONCLUSIONS: Our investigation sought to assess the potential risks associated with hydroxocobalamin administration in burn patients with concomitant inhalation injury. Contrary to our initial hypothesis, we found no statistically significant differences in methemoglobinemia, lactate levels, mortality, or kidney function. The influence of other factors, such as methemoglobinemia-inducing drugs or hydroxocobalamin's interference with co-oximetry, adds complexity. Although elevated methemoglobin levels were observed in some cases, their clinical significance was limited. However, this study's limitations, particularly the rarity of inhalation injury cases with concern for cyanide toxicity, warrant consideration. Further research is required to comprehensively elucidate the impact of hydroxocobalamin administration on burn patients' outcomes.

11.
Clin Ophthalmol ; 18: 1277-1286, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38741583

RESUMO

Purpose: This study aimed to evaluate the accuracy of 12 intraocular lens (IOL) power calculation formulae for eyes that have undergone both radial keratotomy (RK) and laser assisted in situ keratomileusis (LASIK) surgery to determine the efficacy of various IOL calculations for this unique patient group. Currently, research on this surgical topic is limited. Methods: In this retrospective study, 11 eyes from 7 individuals with a history of RK and LASIK who underwent cataract surgery at Hoopes Vision were analyzed. Preoperative biometric and corneal topographic measurements were performed. Subjective refraction was obtained postoperatively. Twelve different intraocular lens (IOL) power calculations were used: Barrett True K No History, Barrett True K (prior LASIK, Prior RK history), Barrett Universal 2, Camellin-Calossi-Camellin (3C), Double K-Modified Holladay, Haigis-L, Galilei, OCT, PEARL-DGS, Potvin-Hill, Panacea, and Shammas. Results: The rankings of mean arithmetic error (MAE), from least to greatest, were as follows: 3C (0.088), Haigis-L-L (-0.508), Shammas (-0.516), OCT Average (-0.538), Barrett True K (-0.557), OCT RK (-0.563), Galilei (-0.570), IOL Master (-0.571), OCT LASIK (-0.583), Barrett True K No History (-0.597), Pearl-DGS (-0.606), Potvin-Hill SF (-0.770), Potvin-Hill TNP (-0.778), Panacea (-0.876), and Barrett Universal 2 (-1.522). The 3C formula achieved the greatest percentage of eyes within ±0.25 D of target range (91%), while Haigis-L, Shammas, Galilei, Potvin Hill, Barrett True K, IOL Master, PEARL-DGS, and OCT formulae performed similarly, achieving 45% of eyes within ±0.75D of target refraction. Conclusion: This study demonstrates the accuracy of the lesser known 3C formula in IOL calculation, particularly for patients who have undergone both RK and LASIK. Well-known formulae, such as Haigis-L, Shammas, and Galilei, which are used by the American Society of Cataract and Refractive Surgery (ASCRS), are viable options, although 3C formulae should be considered in this patient population. Furthermore, larger studies can confirm the best IOL power formulas for post-RK and LASIK cataract patients.

12.
Cureus ; 15(7): e42744, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37529827

RESUMO

Purpose To determine the accuracy of three smartphone applications in the measurement of interpupillary distance (IPD). Methods This study compared measurements from three smartphone applications to measurements obtained by a single trained examiner using a digital pupilometer in 44 subjects. The mean absolute error (MAE) of IPD prediction by each application was compared. Additionally, the frequency at which each application measured IPD within ± 0.05 mm, ± 0.10 mm, ± 0.25 mm, ± 0.50 mm, ± 0.75 mm, and ± 1.00 mm of the digital pupilometer measurement was determined. Results The Eye Measure (Dotty Digital, Sydney, New South Wales, Australia) and Warby Parker (Warby Parker, New York, New York) applications had significantly lower MAE of IPD measurements (0.511364 mm) compared to the PDCheck AR (EyeQue Corp., Newark, California) application (1.375 mm). The Warby Parker application most frequently obtained accurate IPD measurements within the following ranges: ± 0.05 mm, ± 0.10 mm, ± 0.25 mm, ± 0.50 mm, ± 0.75 mm, and ± 1.00 mm. Conclusion Of the three smartphone applications compared in this study, the Warby Parker application performed to the highest degree of accuracy and may serve as an adequate alternative when conventional IPD measurement methods are either unavailable or unable to be performed accurately.

13.
Elife ; 112022 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-35507386

RESUMO

Food intake behavior is regulated by a network of appetite-inducing and appetite-suppressing neuronal populations throughout the brain. The parasubthalamic nucleus (PSTN), a relatively unexplored population of neurons in the posterior hypothalamus, has been hypothesized to regulate appetite due to its connectivity with other anorexigenic neuronal populations and because these neurons express Fos, a marker of neuronal activation, following a meal. However, the individual cell types that make up the PSTN are not well characterized, nor are their functional roles in food intake behavior. Here, we identify and distinguish between two discrete PSTN subpopulations, those that express tachykinin-1 (PSTNTac1 neurons) and those that express corticotropin-releasing hormone (PSTNCRH neurons), and use a panel of genetically encoded tools in mice to show that PSTNTac1 neurons play an important role in appetite suppression. Both subpopulations increase activity following a meal and in response to administration of the anorexigenic hormones amylin, cholecystokinin (CCK), and peptide YY (PYY). Interestingly, chemogenetic inhibition of PSTNTac1, but not PSTNCRH neurons, reduces the appetite-suppressing effects of these hormones. Consistently, optogenetic and chemogenetic stimulation of PSTNTac1 neurons, but not PSTNCRH neurons, reduces food intake in hungry mice. PSTNTac1 and PSTNCRH neurons project to distinct downstream brain regions, and stimulation of PSTNTac1 projections to individual anorexigenic populations reduces food consumption. Taken together, these results reveal the functional properties and projection patterns of distinct PSTN cell types and demonstrate an anorexigenic role for PSTNTac1 neurons in the hormonal and central regulation of appetite.


Assuntos
Regulação do Apetite , Apetite , Animais , Hormônio Liberador da Corticotropina/metabolismo , Ingestão de Alimentos/fisiologia , Camundongos , Neurônios/fisiologia , Optogenética
14.
Nanomaterials (Basel) ; 8(12)2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30563038

RESUMO

Glioblastoma is a particularly challenging cancer, as there are currently limited options for treatment. New delivery routes are being explored, including direct intratumoral injection via convection-enhanced delivery (CED). While promising, convection-enhanced delivery of traditional chemotherapeutics such as doxorubicin (DOX) has seen limited success. Several studies have demonstrated that attaching a drug to polymeric nanoscale materials can improve drug delivery efficacy via CED. We therefore set out to evaluate a panel of morphologically distinct protein nanoparticles for their potential as CED drug delivery vehicles for glioblastoma treatment. The panel consisted of three different virus-like particles (VLPs), MS2 spheres, tobacco mosaic virus (TMV) disks and nanophage filamentous rods modified with DOX. While all three VLPs displayed adequate drug delivery and cell uptake in vitro, increased survival rates were only observed for glioma-bearing mice that were treated via CED with TMV disks and MS2 spheres conjugated to doxorubicin, with TMV-treated mice showing the best response. Importantly, these improved survival rates were observed after only a single VLP⁻DOX CED injection several orders of magnitude smaller than traditional IV doses. Overall, this study underscores the potential of nanoscale chemotherapeutic CED using virus-like particles and illustrates the need for further studies into how the overall morphology of VLPs influences their drug delivery properties.

15.
J Nanosci Nanotechnol ; 7(11): 3902-5, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18047084

RESUMO

The power of nanotechnology is realized in its application in numerous areas. One such area is undoubtedly the use of metallic nanoparticles as a direct write application. An effort in this area has resulted in a conductive ink whose conductivity approaches 60-70% that of the bulk copper. Such an ink has been developed by reducing silver, gold, and copper nano-sized powders by a wet method and followed by a heat treatment at less than 400 degrees C. The conductivity of the resulting ink product was found to be very much affected by how various sizes of metal powders are packed when particles were dried and packed on various substrates. The effect of packing and various kinds of metal powders on the eventual conductivity of the final product of the ink has been described and discussed in this paper.


Assuntos
Cristalização/métodos , Tinta , Metais/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Impressão/métodos , Condutividade Elétrica , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Pós , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA