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1.
J Assoc Physicians India ; 71(10): 83-88, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38716529

RESUMO

Digital technology has encompassed all aspects of healthcare. There are many international and national organizations, guidelines, and formats available in health information systems (HIS), but many are presently still not being used in India. The aim is to give a flawless, secure, and user-friendly health information technology (IT) system for Indian healthcare. We discuss the timeline of digital technology in hospital administration, administrative applications, and the importance of clinical quality in health. Clinical perspectives of clinical information systems (CIS), both in acute as well as chronic clinical care models. Cross-integration of healthcare in IT (HIT) in electronic health records (EHR) or electronic medical records (EMRs), in chronic disease management (CDM) systems, and in clinical decision support systems (CDSS) are elaborated. Also, practical strategic application methods are discussed. The limitations of the current HIS software in India are mostly used for transaction reporting, prescription, and administrative tools. They lack CIS and strategic business applications as compared to mature multinational company (MNC) HIS software. Along with this, various features and levels of HIS Software, challenges of HIT adoption, Indian health IT standards, and the future framework of IT in health in India are systematically analyzed. We aim at all physicians in India and at all levels of practice, from individuals, group practices, health institutes, or corporate hospitals, and to encourage them to make strategic use of CIS and strategic IT applications in their individual practice and hospital management. This will improve clinical outcomes, patient safety, practitioner performance, adherence to treatment guidelines, and reduction in medical errors, along with efficiency improvements and cost reductions. How to cite this article: Taneja D, Kulkarni SV, Sinha S, et al. Digital Technology in Hospital Administration: A Strategic Choice. J Assoc Physicians India 2023;71(10):83-88.


Assuntos
Administração Hospitalar , Humanos , Índia , Administração Hospitalar/métodos , Tecnologia Digital , Sistemas de Apoio a Decisões Clínicas , Registros Eletrônicos de Saúde , Informática Médica/métodos , Sistemas de Informação em Saúde
2.
J Membr Biol ; 255(2-3): 175-184, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35333976

RESUMO

Curvature-inducing proteins are involved in a variety of membrane remodeling processes in the cell. Several in vitro experiments have quantified the curvature sensing behavior of these proteins in model lipid systems. One such system consists of a membrane bilayer laid atop a wavy substrate (Hsieh in Langmuir 28:12838-12843, 2012). In these experiments, the bilayer conforms to the wavy substrate, and curvature-inducing proteins show preferential segregation on the wavy membrane. Using a mesoscale computational membrane model based on the Helfrich Hamiltonian, here we present a study which analyzes the curvature sensing characteristics of this membrane-protein system, and elucidates key physical principles governing protein segregation on the wavy substrate and other in vitro systems. In this article we compute the local protein densities from the free energy landscape associated with membrane remodeling by curvature-inducing proteins. In specific, we use the Widom insertion technique to compute the free energy landscape for an inhomogeneous system with spatially varying density and the results obtained with this minimal model show excellent agreement with experimental studies that demonstrate the association between membrane curvature and local protein density. The free energy-based framework employed in this study can be used for different membrane morphologies and varied protein characteristics to gain mechanistic insights into protein sorting on membranes.


Assuntos
Proteínas de Membrana , Modelos Biológicos , Membrana Celular/metabolismo , Bicamadas Lipídicas/metabolismo , Proteínas de Membrana/metabolismo , Transporte Proteico
3.
Bioinformatics ; 37(16): 2504-2505, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-33459764

RESUMO

SUMMARY: Bistable biochemical switches are key motifs in cellular state decisions and long-term storage of cellular 'memory'. There are a few known biological switches that have been well characterized, however, these examples are insufficient for systematic surveys of properties of these important systems. Here we present a resource of all possible bistable biochemical reaction networks with up to six reactions between three molecules, and three reactions between four molecules. Over 35 000 reaction topologies were constructed by identifying unique combinations of reactions between a fixed number of molecules. Then, these topologies were populated with rates within a biologically realistic range. The Searchable Web Interface for Topologies of CHEmical Switches (SWITCHES, https://switches.ncbs.res.in) provides a bistability and parameter analysis of over seven million models from this systematic survey of chemical reaction space. This database will be useful for theoreticians interested in analyzing stability in chemical systems and also experimentalists for creating robust synthetic biological switches. AVAILABILITY AND IMPLEMENTATION: Freely available on the web at https://switches.ncbs.res.in. Website implemented in PHP, MariaDB, Graphviz and Apache, with all major browsers supported.

4.
Planta ; 253(6): 119, 2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-33963935

RESUMO

MAIN CONCLUSION: This review provides insights into the molecular interactions between Phytophthora infestans and tomato and highlights research gaps that need further attention. Late blight in tomato is caused by the oomycota hemibiotroph Phytophthora infestans, and this disease represents a global threat to tomato farming. The pathogen is cumbersome to control because of its fast-evolving nature, ability to overcome host resistance and inefficient natural resistance obtained from the available tomato germplasm. To achieve successful control over this pathogen, the molecular pathogenicity of P. infestans and key points of vulnerability in the host plant immune system must be understood. This review primarily focuses on efforts to better understand the molecular interaction between host pathogens from both perspectives, as well as the resistance genes, metabolomic changes, quantitative trait loci with potential for improvement in disease resistance and host genome manipulation via transgenic approaches, and it further identifies research gaps and provides suggestions for future research priorities.


Assuntos
Phytophthora infestans , Solanum lycopersicum , Resistência à Doença , Solanum lycopersicum/genética , Doenças das Plantas , Pesquisa
5.
J Heat Transfer ; 141(5): 0524011-524016, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31186582

RESUMO

Describing the hydrodynamics of nanoparticles in fluid media poses interesting challenges due to the coupling between the Brownian and hydrodynamic forces at the nanoscale. We focus on multiscale formulations of Brownian motion and hydrodynamic interactions (HI) of a single flexible polymeric nanoparticle in confining flows using the Brownian Dynamics method. The nanoparticle is modeled as a self-avoiding freely jointed polymer chain that is subject to Brownian forces, hydrodynamics forces, and repulsive interactions with the confining wall. To accommodate the effect of the wall, the hydrodynamic lift due to the wall is included in the mobility of a bead of the polymer chain which depends on its proximity to the wall. Using the example of a flexible polymeric nanoparticle, we illustrate temporal dynamics pertaining to the colloidal scale as well as the nanoscale.

6.
Biophys J ; 114(8): 1830-1846, 2018 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-29694862

RESUMO

We utilize a multiscale modeling framework to study the effect of shape, size, and ligand composition on the efficacy of binding of a ligand-coated particle to a substrate functionalized with the target receptors. First, we show how molecular dynamics along with steered molecular dynamics calculations can be used to accurately parameterize the molecular-binding free energy and the effective spring constant for a receptor-ligand pair. We demonstrate this for two ligands that bind to the α5ß1-domain of integrin. Next, we show how these effective potentials can be used to build computational models at the meso- and continuum-scales. These models incorporate the molecular nature of the receptor-ligand interactions and yet provide an inexpensive route to study the multivalent interaction of receptors and ligands through the construction of Bell potentials customized to the molecular identities. We quantify the binding efficacy of the ligand-coated-particle in terms of its multivalency, binding free-energy landscape, and the losses in the configurational entropies. We show that 1) the binding avidity for particle sizes less than 350 nm is set by the competition between the enthalpic and entropic contributions, whereas that for sizes above 350 nm is dominated by the enthalpy of binding; 2) anisotropic particles display higher levels of multivalent binding compared to those of spherical particles; and 3) variations in ligand composition can alter binding avidity without altering the average multivalency. The methods and results presented here have wide applications in the rational design of functionalized carriers and also in understanding cell adhesion.


Assuntos
Simulação de Dinâmica Molecular , Nanopartículas/química , Tamanho da Partícula , Anisotropia , Entropia , Ligantes , Fenômenos Mecânicos
7.
Phys Biol ; 15(2): 026002, 2018 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-29116056

RESUMO

Thermal fluctuations in cell membranes manifest as an excess area ([Formula: see text]) which governs a multitude of physical process at the sub-micron scale. We present a theoretical framework, based on an in silico tether pulling method, which may be used to reliably estimate [Formula: see text] in live cells. We perform our simulations in two different thermodynamic ensembles: (i) the constant projected area and (ii) the constant frame tension ensembles and show the equivalence of our results in the two. The tether forces estimated from our simulations compare well with our experimental measurements for tethers extracted from ruptured GUVs and HeLa cells. We demonstrate the significance and validity of our method by showing that all our calculations performed in the initial tether formation regime (i.e. when the length of the tether is comparable to its radius) along with experiments of tether extraction in 15 different cell types collapse onto two unified scaling relationships mapping tether force, tether radius, bending stiffness κ, and membrane tension σ. We show that [Formula: see text] is an important determinant of the radius of the extracted tether, which is equal to the characteristic length [Formula: see text] for [Formula: see text], and is equal to [Formula: see text] for [Formula: see text]. We also find that the estimated excess area follows a linear scaling behavior that only depends on the true value of [Formula: see text] for the membrane, based on which we propose a self-consistent technique to estimate the range of excess membrane areas in a cell.


Assuntos
Membrana Celular/fisiologia , Simulação por Computador , Modelos Biológicos , Termodinâmica
8.
Med J Armed Forces India ; 74(2): 116-119, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29692475

RESUMO

BACKGROUND: Nasal symptoms are a major problem affecting the quality of life of lowlanders deployed at high altitude. Study was carried out in fresh male inductees inducted in high altitude of 11,500 ft (3500 m) above sea level to evaluate the nasal obstruction using the subjective Nasal obstruction and symptom evaluation (NOSE) score and rhinomanometry during the stay in high altitude. METHODS: A prospective study was carried out in 100 males inducted into high altitude. The subjects were evaluated using the subjective assessment tool, NOSE scale and rhinomanometry on induction and after 2 months. The data were analysed for NOSE scale in the 1st and 2nd visit by test for equality of proportions and the total nasal airway resistance (Pa) has been expressed as mean ± standard deviation and compared across severity of NOSE score using one way ANOVA and between 1st and 2nd visit using paired t test. RESULTS AND CONCLUSIONS: Out of the 100 subjects, 77 came for the 2nd review after 2 months. There was statistically significant worsening in the subjective feeling of nasal obstruction during the stay in high altitude without any significant change in the nasal airway resistance.

9.
Ann Bot ; 120(6): 893-909, 2017 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-29155926

RESUMO

BACKGROUND AND AIMS: Studies on codon usage in monocots have focused on grasses, and observed patterns of this taxon were generalized to all monocot species. Here, non-grass monocot species were analysed to investigate the differences between grass and non-grass monocots. METHODS: First, studies of codon usage in monocots were reviewed. The current information was then extended regarding codon usage, as well as codon-pair context bias, using four completely sequenced non-grass monocot genomes (Musa acuminata, Musa balbisiana, Phoenix dactylifera and Spirodela polyrhiza) for which comparable transcriptome datasets are available. Measurements were taken regarding relative synonymous codon usage, effective number of codons, derived optimal codon and GC content and then the relationships investigated to infer the underlying evolutionary forces. KEY RESULTS: The research identified optimal codons, rare codons and preferred codon-pair context in the non-grass monocot species studied. In contrast to the bimodal distribution of GC3 (GC content in third codon position) in grasses, non-grass monocots showed a unimodal distribution. Disproportionate use of G and C (and of A and T) in two- and four-codon amino acids detected in the analysis rules out the mutational bias hypothesis as an explanation of genomic variation in GC content. There was found to be a positive relationship between CAI (codon adaptation index; predicts the level of expression of a gene) and GC3. In addition, a strong correlation was observed between coding and genomic GC content and negative correlation of GC3 with gene length, indicating a strong impact of GC-biased gene conversion (gBGC) in shaping codon usage and nucleotide composition in non-grass monocots. CONCLUSION: Optimal codons in these non-grass monocots show a preference for G/C in the third codon position. These results support the concept that codon usage and nucleotide composition in non-grass monocots are mainly driven by gBGC.


Assuntos
Códon/genética , Técnicas Genéticas , Genoma de Planta , Transcriptoma , Araceae/genética , Musa/genética , Phoeniceae/genética
10.
Eur Phys J E Soft Matter ; 40(3): 32, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28324242

RESUMO

The properties of self-avoiding p-atic membranes restricted to spherical topology have been studied by Monte Carlo simulations of a triangulated random surface model. Spherically shaped p-atic membranes undergo a Kosterlitz-Thouless transition as expected with topology induced mutually repelling disclinations of the p-atic ordered phase. For flexible membranes the phase behaviour bears some resemblance to the spherically shaped case with a p-atic disordered crumpled phase and p-atic ordered, conformationally ordered (crinkled) phase separated by a KT-like transition with proliferation of disclinations. We confirm the proposed buckling of disclinations in the p-atic ordered phase, while the expected associated disordering (crumpling) transition at low bending rigidities is absent in the phase diagram.

11.
Nanomedicine ; 13(4): 1495-1506, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28065731

RESUMO

Inflamed organs display marked spatial heterogeneity of inflammation, with patches of inflamed tissue adjacent to healthy tissue. To investigate how nanocarriers (NCs) distribute between such patches, we created a mouse model that recapitulates the spatial heterogeneity of the inflammatory lung disease ARDS. NCs targeting the epitope PECAM strongly accumulated in the lungs, but were shunted away from inflamed lung regions due to hypoxic vasoconstriction (HVC). In contrast, ICAM-targeted NCs, which had lower whole-lung uptake than PECAM/NCs in inflamed lungs, displayed markedly higher NC levels in inflamed regions than PECAM/NCs, due to increased regional ICAM. Regional HVC, epitope expression, and capillary leak were sufficient to predict intra-organ of distribution of NCs, antibodies, and drugs. Importantly, these effects were not observable with traditional spatially-uniform models of ARDS, nor when examining only whole-organ uptake. This study underscores how examining NCs' intra-organ distribution in spatially heterogeneous animal models can guide rational NC design.


Assuntos
Portadores de Fármacos/farmacocinética , Epitopos/imunologia , Inflamação/patologia , Pulmão/patologia , Nanopartículas/química , Animais , Anticorpos/química , Portadores de Fármacos/química , Epitopos/química , Hipóxia/fisiopatologia , Inflamação/metabolismo , Molécula 1 de Adesão Intercelular/imunologia , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Molécula-1 de Adesão Celular Endotelial a Plaquetas/imunologia , Síndrome do Desconforto Respiratório/metabolismo , Síndrome do Desconforto Respiratório/patologia , Vasoconstrição
12.
Indian J Public Health ; 60(2): 112-7, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27350704

RESUMO

BACKGROUND: Different studies in India have shown that more than 50% of elderly population of India are suffering from malnutrition and more than 90% have less than recommended intake. OBJECTIVES: The aim of this study is to estimate the prevalence and correlates of malnutrition among elderly aged 60 years and above in an urban area in Coimbatore using Mini Nutritional Assessment (MNA). METHODS: A cross-sectional study was conducted on 154 households and 190 elderly were interviewed. Nutritional status was assessed using the MNA questionnaire. RESULTS: Mean (standard deviation) age of the total population (n = 190) was 71.09 (7.93) years and 30% was male. In this population, 37 (19.47%) was malnourished (MNA <17.0) and 47 (24.73%) were at risk for malnutrition (MNA 17.0-23.5). No significant association was observed between smoking, current alcohol consumption, higher medication use, higher comorbidity, and use of walk aid with malnutrition. Among the social factors studied, lower socioeconomic status compared to higher socioeconomic status (adjusted odds ratio [OR] =5.031, P < 0.001), single/widowed/divorced compared to married (adjusted OR = 3.323, P < 0.05), and no pension compared to those having pension (adjusted OR = 3.239, P < 0.05) were significantly associated with malnutrition. CONCLUSION: The prevalence of malnutrition observed in the aged people is unacceptably high. The increasing total number of lifestyle, somatic, functional, and social factors was associated with lower MNA scores. The findings of the present study clearly indicate that malnutrition is a multifactorial condition associated with sociodemographic, somatic, and functional status. Hence, we recommend that the treatment of malnutrition should be multifactorial, and the treatment team should be multidisciplinary. Further research is needed to develop appropriate guidelines for nutritional screening and interventional programs among geriatric population.


Assuntos
Desnutrição , Idoso , Estudos Transversais , Feminino , Avaliação Geriátrica , Humanos , Índia , Masculino , Desnutrição/epidemiologia , Avaliação Nutricional , Estado Nutricional , Prevalência , Fatores de Risco , População Urbana
13.
Soft Matter ; 11(12): 2387-93, 2015 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-25672939

RESUMO

Intracellular organelles are subject to a steady flux of lipids and proteins through active, energy consuming transport processes. Active fission and fusion are promoted by GTPases, e.g., Arf-Coatamer and the Rab-Snare complexes, which both sense and generate local membrane curvature. Here we investigate, through Dynamical Triangulation Monte Carlo simulations, the role that these active processes play in determining the morphology and composition segregation in closed membranes. We find that the steady state shapes obtained as a result of such active processes, bear a striking resemblance to the ramified morphologies of organelles in vivo, pointing to the relevance of nonequilibrium fission-fusion in organelle morphogenesis.


Assuntos
Membranas Intracelulares/química , Organelas/química , Membranas Intracelulares/metabolismo , Fusão de Membrana , Modelos Biológicos , Modelos Estatísticos , Método de Monte Carlo , Organelas/metabolismo
14.
Indian J Chest Dis Allied Sci ; 57(1): 48-64, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26410986

RESUMO

Obstructive sleep apnoea (OSA) and obstructive sleep apnoea syndrome (OSAS) are subsets of sleep-disordered breathing. Awareness about OSA and its consequences amongst the general public as well as the majority of primary care physcians across India is poor. This necessiated the development of the INdian initiative on Obstructive Sleep Apnoea (INOSA) guidelines under the auspices of Department of Health Research, Ministry of Health & Family Welfare, Government of India. OSA is the occurrence of an average five or more episodes of obstructive respiratory events per hour of sleep with either sleep related symptoms or comorbidities or ≥ 15 such episodes without any sleep related symptoms or comorbidities. OSAS is defined as OSA associated with daytime symptoms, most often excessive sleepiness. Patients undergoing routine health check-up with snoring, daytime sleepiness, obesity, hypertension, motor vehicular accidents and high risk cases should undergo a comprehensive sleep evaluation. Medical examiners evaluating drivers, air pilots, railway drivers and heavy machinery workers should be educated about OSA and should comprehensively evaluate applicants for OSA. Those suspected to have OSA on comprehensive sleep evaluation should be referred for a sleep study. Supervised overnight polysomnography (PSG) is the "gold standard" for evaluation of OSA. Positive airway pressure (PAP) therapy is the mainstay of treatment of OSA. Oral appliances are indicated for use in patients with mild to moderate OSA who prefer oral appliances to PAP, or who do not respond to PAP or who fail treatment attempts with PAP or behavioural measures. Surgical treatment is recommended in patients who have failed or are intolerant to PAP therapy.


Assuntos
Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/terapia , Humanos , Índia , Apneia Obstrutiva do Sono/epidemiologia
15.
Phys Rep ; 543(1): 1-60, 2014 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25484487

RESUMO

Biological membranes constitute boundaries of cells and cell organelles. These membranes are soft fluid interfaces whose thermodynamic states are dictated by bending moduli, induced curvature fields, and thermal fluctuations. Recently, there has been a flood of experimental evidence highlighting active roles for these structures in many cellular processes ranging from trafficking of cargo to cell motility. It is believed that the local membrane curvature, which is continuously altered due to its interactions with myriad proteins and other macromolecules attached to its surface, holds the key to the emergent functionality in these cellular processes. Mechanisms at the atomic scale are dictated by protein-lipid interaction strength, lipid composition, lipid distribution in the vicinity of the protein, shape and amino acid composition of the protein, and its amino acid contents. The specificity of molecular interactions together with the cooperativity of multiple proteins induce and stabilize complex membrane shapes at the mesoscale. These shapes span a wide spectrum ranging from the spherical plasma membrane to the complex cisternae of the Golgi apparatus. Mapping the relation between the protein-induced deformations at the molecular scale and the resulting mesoscale morphologies is key to bridging cellular experiments across the various length scales. In this review, we focus on the theoretical and computational methods used to understand the phenomenology underlying protein-driven membrane remodeling. Interactions at the molecular scale can be computationally probed by all atom and coarse grained molecular dynamics (MD, CGMD), as well as dissipative particle dynamics (DPD) simulations, which we only describe in passing. We choose to focus on several continuum approaches extending the Canham - Helfrich elastic energy model for membranes to include the effect of curvature-inducing proteins and explore the conformational phase space of such systems. In this description, the protein is expressed in the form of a spontaneous curvature field. The approaches include field theoretical methods limited to the small deformation regime, triangulated surfaces and particle-based computational models to investigate the large-deformation regimes observed in the natural state of many biological membranes. Applications of these methods to understand the properties of biological membranes in homogeneous and inhomogeneous environments of proteins, whose underlying curvature fields are either isotropic or anisotropic, are discussed. The diversity in the curvature fields elicits a rich variety of morphological states, including tubes, discs, branched tubes, and caveola. Mapping the thermodynamic stability of these states as a function of tuning parameters such as concentration and strength of curvature induction of the proteins is discussed. The relative stabilities of these self-organized shapes are examined through free-energy calculations. The suite of methods discussed here can be tailored to applications in specific cellular settings such as endocytosis during cargo trafficking and tubulation of filopodial structures in migrating cells, which makes these methods a powerful complement to experimental studies.

16.
Indian J Med Res ; 140(3): 451-68, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25366217

RESUMO

Obstructive sleep apnoea (OSA) and obstructive sleep apnoea syndrome (OSAS) are subsets of sleep-disordered breathing. Awareness about OSA and its consequences amongst the general public as well as the majority of primary care physcians across India is poor. This necessiated the development of the INdian initiative on Obstructive sleep apnoea (INOSA) guidelines under the auspices of Department of Health Research, Ministry of Health & Family Welfare, Government of India. OSA is the occurrence of an average five or more episodes of obstructive respiratory events per hour of sleep with either sleep related symptoms or co-morbidities or ≥ 15 such episodes without any sleep related symptoms or co-morbidities. OSAS is defined as OSA associated with daytime symptoms, most often excessive sleepiness. Patients undergoing routine health check-up with snoring, daytime sleepiness, obesity, hypertension, motor vehicular accidents and high risk cases should undergo a comprehensive sleep evaluation. Medical examiners evaluating drivers, air pilots, railway drivers and heavy machinery workers should be educated about OSA and should comprehensively evaluate applicants for OSA. Those suspected to have OSA on comprehensive sleep evaluation should be referred for a sleep study. Supervised overnight polysomnography (PSG) is the "gold standard" for evaluation of OSA. Positive airway pressure (PAP) therapy is the mainstay of treatment of OSA. Oral appliances are indicated for use in patients with mild to moderate OSA who prefer oral appliances to PAP, or who do not respond to PAP or who fail treatment attempts with PAP or behavioural measures. Surgical treatment is recommended in patients who have failed or are intolerant to PAP therapy.


Assuntos
Cirurgia Bariátrica , Apneia Obstrutiva do Sono/cirurgia , Guias como Assunto , Humanos , Índia , Polissonografia , Apneia Obstrutiva do Sono/diagnóstico por imagem , Apneia Obstrutiva do Sono/fisiopatologia , Ronco/fisiopatologia , Ronco/cirurgia , Ultrassonografia
17.
Mechanobiol Med ; 2(3)2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38899029

RESUMO

A definitive understanding of the interplay between protein binding/migration and membrane curvature evolution is emerging but needs further study. The mechanisms defining such phenomena are critical to intracellular transport and trafficking of proteins. Among trafficking modalities, exosomes have drawn attention in cancer research as these nano-sized naturally occurring vehicles are implicated in intercellular communication in the tumor microenvironment, suppressing anti-tumor immunity and preparing the metastatic niche for progression. A significant question in the field is how the release and composition of tumor exosomes are regulated. In this perspective article, we explore how physical factors such as geometry and tissue mechanics regulate cell cortical tension to influence exosome production by co-opting the biophysics as well as the signaling dynamics of intracellular trafficking pathways and how these exosomes contribute to the suppression of anti-tumor immunity and promote metastasis. We describe a multiscale modeling approach whose impact goes beyond the fundamental investigation of specific cellular processes toward actual clinical translation. Exosomal mechanisms are critical to developing and approving liquid biopsy technologies, poised to transform future non-invasive, longitudinal profiling of evolving tumors and resistance to cancer therapies to bring us one step closer to the promise of personalized medicine.

18.
Methods Enzymol ; 701: 359-386, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39025576

RESUMO

In this chapter, we aim to bridge basic molecular and cellular principles surrounding membrane curvature generation with rewiring of cellular signals in cancer through multiscale models. We describe a general framework that integrates signaling with other cellular functions like trafficking, cell-cell and cell-matrix adhesion, and motility. The guiding question in our approach is: how does a physical change in cell membrane configuration caused by external stimuli (including those by the extracellular microenvironment) alter trafficking, signaling and subsequent cell fate? We answer this question by constructing a modeling framework based on stochastic spatial continuum models of cell membrane deformations. We apply this framework to explore the link between trafficking, signaling in the tumor microenvironment, and cell fate. At each stage, we aim to connect the results of our predictions with cellular experiments.


Assuntos
Membrana Celular , Modelos Biológicos , Neoplasias , Microambiente Tumoral , Humanos , Membrana Celular/metabolismo , Neoplasias/patologia , Neoplasias/metabolismo , Microambiente Tumoral/fisiologia , Transdução de Sinais , Termodinâmica , Animais
19.
Biophys J ; 104(5): 1018-28, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23473484

RESUMO

The shapes of cell membranes are largely regulated by membrane-associated, curvature-active proteins. Herein, we use a numerical model of the membrane, recently developed by us, with elongated membrane inclusions possessing spontaneous directional curvatures that could be different along, and perpendicular to, the membrane's long axis. We show that, due to membrane-mediated interactions, these curvature-inducing membrane-nematogens can aggregate spontaneously, even at low concentrations, and change the local shape of the membrane. We demonstrate that for a large group of such inclusions, where the two spontaneous curvatures have equal sign, the tubular conformation and sometimes the sheet conformation of the membrane are the common equilibrium shapes. We elucidate the factors necessary for the formation of these protein lattices. Furthermore, the elastic properties of the tubes, such as their compressional stiffness and persistence length, are calculated. Finally, we discuss the possible role of nematic disclination in capping and branching of the tubular membranes.


Assuntos
Membrana Celular/química , Modelos Moleculares , Cristais Líquidos/química , Lipídeos de Membrana/química , Proteínas de Membrana/química , Estrutura Terciária de Proteína
20.
Sensors (Basel) ; 13(2): 2164-75, 2013 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-23389346

RESUMO

In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW) device is investigated through finite element method (FEM) simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher) than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

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