Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Mol Cell ; 84(10): 1995-2005.e7, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38614096

RESUMO

Cytokines regulate immune responses by binding to cell surface receptors, including the common subunit beta (ßc), which mediates signaling for GM-CSF, IL-3, and IL-5. Despite known roles in inflammation, the structural basis of IL-5 receptor activation remains unclear. We present the cryo-EM structure of the human IL-5 ternary receptor complex, revealing architectural principles for IL-5, GM-CSF, and IL-3. In mammalian cell culture, single-molecule imaging confirms hexameric IL-5 complex formation on cell surfaces. Engineered chimeric receptors show that IL-5 signaling, as well as IL-3 and GM-CSF, can occur through receptor heterodimerization, obviating the need for higher-order assemblies of ßc dimers. These findings provide insights into IL-5 and ßc receptor family signaling mechanisms, aiding in the development of therapies for diseases involving deranged ßc signaling.


Assuntos
Microscopia Crioeletrônica , Fator Estimulador de Colônias de Granulócitos e Macrófagos , Interleucina-3 , Multimerização Proteica , Transdução de Sinais , Humanos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/química , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Interleucina-3/metabolismo , Interleucina-3/química , Interleucina-3/genética , Células HEK293 , Ligação Proteica , Modelos Moleculares , Interleucina-5/metabolismo , Subunidade beta Comum dos Receptores de Citocinas/metabolismo , Subunidade beta Comum dos Receptores de Citocinas/genética , Subunidade beta Comum dos Receptores de Citocinas/química , Imagem Individual de Molécula , Relação Estrutura-Atividade , Sítios de Ligação , Receptores de Interleucina-5/metabolismo , Receptores de Interleucina-5/genética , Receptores de Interleucina-5/química
2.
Immunity ; 53(6): 1230-1244.e5, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33096040

RESUMO

Polyreactivity is the ability of a single antibody to bind to multiple molecularly distinct antigens and is a common feature of antibodies induced upon pathogen exposure. However, little is known about the role of polyreactivity during anti-influenza virus antibody responses. By analyzing more than 500 monoclonal antibodies (mAbs) derived from B cells induced by numerous influenza virus vaccines and infections, we found mAbs targeting conserved neutralizing influenza virus hemagglutinin epitopes were polyreactive. Polyreactive mAbs were preferentially induced by novel viral exposures due to their broad viral binding breadth. Polyreactivity augmented mAb viral binding strength by increasing antibody flexibility, allowing for adaption to imperfectly conserved epitopes. Lastly, we found affinity-matured polyreactive B cells were typically derived from germline polyreactive B cells that were preferentially selected to participate in B cell responses over time. Together, our data reveal that polyreactivity is a beneficial feature of antibodies targeting conserved epitopes.


Assuntos
Linfócitos B/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Orthomyxoviridae/imunologia , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Afinidade de Anticorpos , Anticorpos Amplamente Neutralizantes/genética , Reações Cruzadas , Epitopos de Linfócito B/imunologia , Genes de Imunoglobulinas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Orthomyxoviridae/classificação , Domínios Proteicos , Hipermutação Somática de Imunoglobulina
3.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34548394

RESUMO

Microorganisms have coevolved diverse mechanisms to impair host defenses. A major one, superantigens, can result in devastating effects on the immune system. While all known superantigens induce vast immune cell proliferation and come from opportunistic pathogens, recently, proteins with similar broad specificity to antibody variable (V) domain families were identified in a commensal microbiota. These proteins, identified in the human commensal Ruminococcus gnavus, are called immunoglobulin-binding protein (Ibp) A and B and have been shown to activate B cells in vitro expressing either human VH3 or murine VH5/6/7. Here, we provide molecular and functional studies revealing the basis of this Ibp/immunoglobulin (Ig) interaction. The crystal structure and biochemical assays of a truncated IbpA construct in complex with mouse VH5 antigen-binding fragment (Fab) shows a binding of Ig heavy chain framework residues to the Ibp Domain D and the C-terminal heavy chain binding domain (HCBD). We used targeted mutagenesis of contact residues and affinity measurements and performed studies of the Fab-IbpA complex to determine the stoichiometry between Ibp and VH domains, suggesting Ibp may serve to cluster full-length IgA antibodies in vivo. Furthermore, in vitro stimulation experiments indicate that binding of the Ibp HCBD alone is sufficient to activate responsive murine B cell receptors. The presence of these proteins in a commensal microbe suggest that binding a broad repertoire of immunoglobulins, particularly in the gut/microbiome environment, may provide an important function in the maintenance of host/microbiome homeostasis contrasting with the pathogenic role of structurally homologous superantigens expressed by pathogens.


Assuntos
Anticorpos Monoclonais/metabolismo , Linfócitos B/metabolismo , Clostridiales/metabolismo , Cadeias Pesadas de Imunoglobulinas/metabolismo , Região Variável de Imunoglobulina/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Superantígenos/metabolismo , Animais , Anticorpos Monoclonais/química , Linfócitos B/imunologia , Sítios de Ligação , Clostridiales/crescimento & desenvolvimento , Humanos , Cadeias Pesadas de Imunoglobulinas/química , Região Variável de Imunoglobulina/química , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos B/química , Superantígenos/química
4.
Sensors (Basel) ; 24(11)2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38894336

RESUMO

The paranasal sinuses, a bilaterally symmetrical system of eight air-filled cavities, represent one of the most complex parts of the equine body. This study aimed to extract morphometric measures from computed tomography (CT) images of the equine head and to implement a clustering analysis for the computer-aided identification of age-related variations. Heads of 18 cadaver horses, aged 2-25 years, were CT-imaged and segmented to extract their volume, surface area, and relative density from the frontal sinus (FS), dorsal conchal sinus (DCS), ventral conchal sinus (VCS), rostral maxillary sinus (RMS), caudal maxillary sinus (CMS), sphenoid sinus (SS), palatine sinus (PS), and middle conchal sinus (MCS). Data were grouped into young, middle-aged, and old horse groups and clustered using the K-means clustering algorithm. Morphometric measurements varied according to the sinus position and age of the horses but not the body side. The volume and surface area of the VCS, RMS, and CMS increased with the age of the horses. With accuracy values of 0.72 for RMS, 0.67 for CMS, and 0.31 for VCS, the possibility of the age-related clustering of CT-based 3D images of equine paranasal sinuses was confirmed for RMS and CMS but disproved for VCS.


Assuntos
Imageamento Tridimensional , Seios Paranasais , Cavalos , Animais , Análise por Conglomerados , Seios Paranasais/diagnóstico por imagem , Imageamento Tridimensional/métodos , Tomografia Computadorizada Multidetectores/métodos , Algoritmos
5.
BMC Vet Res ; 19(1): 116, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37559089

RESUMO

BACKGROUND: Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) syndrome is a dental disease where the radiographic signs may be quantified using radiographic texture features. This study aimed to implement the scaled-pixel-counting protocol to quantify and compare the image structure of teeth and the density standard in order to improve the identification of the radiographic signs of tooth resorption and hypercementosis using the EOTRH syndrome model. METHODS AND RESULTS: A detailed examination of the oral cavity was performed in 80 horses and maxillary incisor teeth were evaluated radiographically, including an assessment of the density standard. On each of the radiographs, pixel brightness (PB) was extracted for each of the ten steps of the density standard (S1-S10). Then, each evaluated incisor tooth was assigned to one of 0-3 EOTRH grade-related groups and annotated using region of interest (ROI). For each ROI, the number of pixels (NP) from each range was calculated. The linear relation between an original X-ray beam attenuation and PB was confirmed for the density standard. The NP values increased with the number of steps of the density standard as well as with EOTRH degrees. Similar accuracy of the EOTRH grade differentiation was noted for data pairs EOTRH 0-3 and EOTRH 0-1, allowing for the differentiation of both late and early radiographic signs of EOTRH. CONCLUSION: The scaled-pixel-counting protocol based on the use of density standard has been successfully implemented for the differentiation of radiographic signs of EOTRH degrees.


Assuntos
Doenças dos Cavalos , Hipercementose , Reabsorção de Dente , Cavalos , Animais , Hipercementose/veterinária , Incisivo/diagnóstico por imagem , Doenças dos Cavalos/diagnóstico , Reabsorção de Dente/diagnóstico por imagem , Reabsorção de Dente/veterinária , Radiografia Dentária/veterinária
6.
Proc Natl Acad Sci U S A ; 117(12): 6697-6707, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32139608

RESUMO

Vγ9Vδ2 T cells are a major γδ T cell population in the human blood expressing a characteristic Vγ9JP rearrangement paired with Vδ2. This cell subset is activated in a TCR-dependent and MHC-unrestricted fashion by so-called phosphoantigens (PAgs). PAgs can be microbial [(E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate, HMBPP] or endogenous (isopentenyl pyrophosphate, IPP) and PAg sensing depends on the expression of B7-like butyrophilin (BTN3A, CD277) molecules. IPP increases in some transformed or aminobisphosphonate-treated cells, rendering those cells a target for Vγ9Vδ2 T cells in immunotherapy. Yet, functional Vγ9Vδ2 T cells have only been described in humans and higher primates. Using a genome-based study, we showed in silico translatable genes encoding Vγ9, Vδ2, and BTN3 in a few nonprimate mammalian species. Here, with the help of new monoclonal antibodies, we directly identified a T cell population in the alpaca (Vicugna pacos), which responds to PAgs in a BTN3-dependent fashion and shows typical TRGV9- and TRDV2-like rearrangements. T cell receptor (TCR) transductants and BTN3-deficient human 293T cells reconstituted with alpaca or human BTN3 or alpaca/human BTN3 chimeras showed that alpaca Vγ9Vδ2 TCRs recognize PAg in the context of human and alpaca BTN3. Furthermore, alpaca BTN3 mediates PAg recognition much better than human BTN3A1 alone and this improved functionality mapped to the transmembrane/cytoplasmic part of alpaca BTN3. In summary, we found remarkable similarities but also instructive differences of PAg-recognition by human and alpaca, which help in better understanding the molecular mechanisms controlling the activation of this prominent population of γδ T cells.


Assuntos
Anticorpos Monoclonais/imunologia , Butirofilinas/metabolismo , Hemiterpenos/farmacologia , Ativação Linfocitária/imunologia , Compostos Organofosforados/farmacologia , Subpopulações de Linfócitos T/imunologia , Animais , Butirofilinas/antagonistas & inibidores , Butirofilinas/genética , Butirofilinas/imunologia , Sistemas CRISPR-Cas , Camelídeos Americanos , Feminino , Células HEK293 , Humanos , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Ligação Proteica , Receptores de Antígenos de Linfócitos T gama-delta/efeitos dos fármacos , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/metabolismo
7.
Sensors (Basel) ; 23(1)2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36617105

RESUMO

Human gait recognition is one of the most interesting issues within the subject of behavioral biometrics. The most significant problems connected with the practical application of biometric systems include their accuracy as well as the speed at which they operate, understood both as the time needed to recognize a particular person as well as the time necessary to create and train a biometric system. The present study made use of an ensemble of heterogeneous base classifiers to address these issues. A Heterogeneous ensemble is a group of classification models trained using various algorithms and combined to output an effective recognition A group of parameters identified on the basis of ground reaction forces was accepted as input signals. The proposed solution was tested on a sample of 322 people (5980 gait cycles). Results concerning the accuracy of recognition (meaning the Correct Classification Rate quality at 99.65%), as well as operation time (meaning the time of model construction at <12.5 min and the time needed to recognize a person at <0.1 s), should be considered as very good and exceed in quality other methods so far described in the literature.


Assuntos
Algoritmos , Biometria , Humanos , Marcha
8.
Sensors (Basel) ; 23(21)2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37960639

RESUMO

Dental diagnostic imaging has progressed towards the use of advanced technologies such as 3D image processing. Since multidetector computed tomography (CT) is widely available in equine clinics, CT-based anatomical 3D models, segmentations, and measurements have become clinically applicable. This study aimed to use a 3D segmentation of CT images and volumetric measurements to investigate differences in the surface area and volume of equine incisors. The 3D Slicer was used to segment single incisors of 50 horses' heads and to extract volumetric features. Axial vertical symmetry, but not horizontal, of the incisors was evidenced. The surface area and volume differed significantly between temporary and permanent incisors, allowing for easy eruption-related clustering of the CT-based 3D images with an accuracy of >0.75. The volumetric features differed partially between center, intermediate, and corner incisors, allowing for moderate location-related clustering with an accuracy of >0.69. The volumetric features of mandibular incisors' equine odontoclastic tooth resorption and hypercementosis (EOTRH) degrees were more than those for maxillary incisors; thus, the accuracy of EOTRH degree-related clustering was >0.72 for the mandibula and >0.33 for the maxilla. The CT-based 3D images of equine incisors can be successfully segmented using the routinely achieved multidetector CT data sets and the proposed data-processing approaches.


Assuntos
Hipercementose , Reabsorção de Dente , Cavalos , Animais , Incisivo/diagnóstico por imagem , Tomografia Computadorizada Multidetectores , Reabsorção de Dente/veterinária , Hipercementose/veterinária , Análise por Conglomerados , Maxila
9.
Int J Mol Sci ; 24(2)2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36675294

RESUMO

The work is devoted to preparing and characterizing the properties of photosensitive composites, based on chitosan proposed for photodynamic therapy. Chitosan films with a 5% addition of two BODIPY dyes were prepared by solution casting. These dyes are dipyrromethene boron derivatives with N-alkyl phthalimide substituent, differing in the presence of iodine atoms in positions 2 and 6 of the BODIPY core. The spectral properties of the obtained materials have been studied by infrared and UV-vis absorption spectroscopy and fluorescence, both in solutions and in a solid state. Surface properties were investigated using the contact angle measurement. The morphology of the sample has been characterized by Scanning Electron and Atomic Force Microscopy. Particular attention was paid to studying the protein absorption and kinetics of the dye release from the chitosan. Adding BODIPY to the chitosan matrix leads to a slight increase in hydrophilicity, higher structure heterogeneity, and roughness, than pure chitosan. The presence of iodine atoms in the BODIPY structure caused the bathochromic effect, but the emission quantum yield decreased in the composites. It has been found that BODIPY-doped chitosan interacts better with human serum albumin and acidic α-glycoprotein than unmodified chitosan. The release rate of dyes from films immersed in methanol depends on the iodine present in the structure.


Assuntos
Quitosana , Corantes Fluorescentes , Humanos , Corantes Fluorescentes/química , Boro/química
10.
Int J Mol Sci ; 24(13)2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37446300

RESUMO

Clopidogrel is a chiral compound widely used as an antiplatelet medication that lowers the risk of blood clots, strokes, and heart attacks. The main aim of the study presented herein was to obtain (S)-clopidogrel, which is commercially available in treatments, via the kinetic resolution of racemic clopidogrel carboxylic acid with the use of lipase from Candida rugosa and a two-phase reaction medium containing an ionic liquid. For this purpose, the enantioselective biotransformation of clopidogrel carboxylic acid and chiral chromatographic separation with the use of a UPLC-MS/MS system were optimized. The best kinetic resolution parameters were obtained by using a catalytic system containing lipase from Candida rugosa OF as a biocatalyst, cyclohexane and [EMIM][BF4] as a two-phase reaction medium, and methanol as an acyl acceptor. The enantiomeric excess of the product was eep = 94.21% ± 1.07 and the conversion was c = 49.60% ± 0.57%, whereas the enantioselectivity was E = 113.40 ± 1.29. The performed study proved the possibility of obtaining (S)-clopidogrel with the use of lipase as a biocatalyst and a two-phase reaction medium containing an ionic liquid, which is in parallel with green chemistry methodology and does not require environmentally harmful conditions.


Assuntos
Líquidos Iônicos , Clopidogrel , Cromatografia Líquida , Espectrometria de Massas em Tandem , Lipase/metabolismo , Estereoisomerismo
11.
Sensors (Basel) ; 22(8)2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35458905

RESUMO

Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is one of the horses' dental diseases, mainly affecting the incisor teeth. An increase in the incidence of aged horses and a painful progressive course of the disease create the need for improved early diagnosis. Besides clinical findings, EOTRH recognition is based on the typical radiographic findings, including levels of dental resorption and hypercementosis. This study aimed to introduce digital processing methods to equine dental radiographic images and identify texture features changing with disease progression. The radiographs of maxillary incisor teeth from 80 horses were obtained. Each incisor was annotated by separate masks and clinically classified as 0, 1, 2, or 3 EOTRH degrees. Images were filtered by Mean, Median, Normalize, Bilateral, Binomial, CurvatureFlow, LaplacianSharpening, DiscreteGaussian, and SmoothingRecursiveGaussian filters independently, and 93 features of image texture were extracted using First Order Statistics (FOS), Gray Level Co-occurrence Matrix (GLCM), Neighbouring Gray Tone Difference Matrix (NGTDM), Gray Level Dependence Matrix (GLDM), Gray Level Run Length Matrix (GLRLM), and Gray Level Size Zone Matrix (GLSZM) approaches. The most informative processing was selected. GLCM and GLRLM return the most favorable features for the quantitative evaluation of radiographic signs of the EOTRH syndrome, which may be supported by filtering by filters improving the edge delimitation.


Assuntos
Doenças dos Cavalos , Hipercementose , Reabsorção de Dente , Animais , Doenças dos Cavalos/diagnóstico por imagem , Cavalos , Hipercementose/diagnóstico por imagem , Hipercementose/veterinária , Incisivo/diagnóstico por imagem , Radiografia , Reabsorção de Dente/diagnóstico por imagem , Reabsorção de Dente/veterinária
12.
Sensors (Basel) ; 22(16)2022 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-36015813

RESUMO

As obesity is a serious problem in the human population, overloading of the horse's thoracolumbar region often affects sport and school horses. The advances in using infrared thermography (IRT) to assess the horse's back overload will shortly integrate the IRT-based rider-horse fit into everyday equine practice. This study aimed to evaluate the applicability of entropy measures to select the most informative measures and color components, and the accuracy of rider:horse bodyweight ratio detection. Twelve horses were ridden by each of the six riders assigned to the light, moderate, and heavy groups. Thermal images were taken pre- and post-exercise. For each thermal image, two-dimensional sample (SampEn), fuzzy (FuzzEn), permutation (PermEn), dispersion (DispEn), and distribution (DistEn) entropies were measured in the withers and the thoracic spine areas. Among 40 returned measures, 30 entropy measures were exercise-dependent, whereas 8 entropy measures were bodyweight ratio-dependent. Moreover, three entropy measures demonstrated similarities to entropy-related gray level co-occurrence matrix (GLCM) texture features, confirming the higher irregularity and complexity of thermal image texture when horses worked under heavy riders. An application of DispEn to red color components enables identification of the light and heavy rider groups with higher accuracy than the previously used entropy-related GLCM texture features.


Assuntos
Esportes , Termografia , Animais , Dorso , Fenômenos Biomecânicos , Peso Corporal , Entropia , Cavalos , Humanos
13.
Int J Mol Sci ; 23(5)2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35269605

RESUMO

Levan, as a biocompatible and renewable biopolymer with anticancer properties, is a promising candidate for a wide range of applications in various fields of industry. However, in the literature, there is a lack of information about its behavior under the influence of UV irradiation, which may limit its potential application, including medical science. Therefore, this study describes the effects of irradiation on the structural properties of levan. This type of fructan was subjected to stability tests under radiation conditions using LED and polychromatic lamps. The results showed that the photodegradation of levan irradiated with a polychromatic light occurs faster and more efficiently than the photodegradation of levan irradiated with an LED lamp. Furthermore, AFM analysis showed that the surface became smoother after irradiation, as evidenced by decreasing values of roughness parameters. Moreover, UV irradiation causes the decrease of total surface free energy and both its components in levan; however, more significant changes occur during irradiation of the sample with a polychromatic lamp.


Assuntos
Frutanos , Biopolímeros/química , Frutanos/química
14.
Int J Mol Sci ; 23(17)2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-36077096

RESUMO

In this study, thin chitosan-gelatin biofilms cross-linked with dialdehyde cellulose nanocrystals for dressing materials were received. Two types of dialdehyde cellulose nanocrystals from fiber (DNCL) and microcrystalline cellulose (DAMC) were obtained by periodate oxidation. An ATR-FTIR analysis confirmed the selective oxidation of cellulose nanocrystals with the creation of a carbonyl group at 1724 cm-1. A higher degree of cross-linking was obtained in chitosan-gelatin biofilms with DNCL than with DAMC. An increasing amount of added cross-linkers resulted in a decrease in the apparent density value. The chitosan-gelatin biofilms cross-linked with DNCL exhibited a higher value of roughness parameters and antioxidant activity compared with materials cross-linked with DAMC. The cross-linking process improved the oxygen permeability and anti-inflammatory properties of both measurement series. Two samples cross-linked with DNCL achieved an ideal water vapor transition rate for wound dressings, CS-Gel with 10% and 15% addition of DNCL-8.60 and 9.60 mg/cm2/h, respectively. The swelling ability and interaction with human serum albumin (HSA) were improved for biofilms cross-linked with DAMC and DNCL. Significantly, the films cross-linked with DAMC were characterized by lower toxicity. These results confirmed that chitosan-gelatin biofilms cross-linked with DNCL and DAMC had improved properties for possible use in wound dressings.


Assuntos
Quitosana , Nanopartículas , Bandagens , Celulose/análogos & derivados , Celulose/química , Quitosana/química , Gelatina/química , Humanos
15.
Int J Mol Sci ; 23(14)2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35886996

RESUMO

In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5-15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.


Assuntos
Proteínas Sanguíneas , Quitosana , Reagentes de Ligações Cruzadas , Gelatina , Nanopartículas , Amido , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Proteínas Sanguíneas/química , Proteínas Sanguíneas/metabolismo , Quitosana/química , Quitosana/metabolismo , Reagentes de Ligações Cruzadas/química , Reagentes de Ligações Cruzadas/metabolismo , Gelatina/química , Gelatina/metabolismo , Humanos , Nanopartículas/química , Nanopartículas/metabolismo , Amido/análogos & derivados , Amido/química , Amido/metabolismo
16.
BMC Vet Res ; 17(1): 99, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33653346

RESUMO

BACKGROUND: The horses' backs are particularly exposed to overload and injuries due to direct contact with the saddle and the influence of e.g. the rider's body weight. The maximal load for a horse's back during riding has been suggested not to exceed 20% of the horses' body weight. The common prevalence of back problems in riding horses prompted the popularization of thermography of the thoracolumbar region. However, the analysis methods of thermographic images used so far do not distinguish loaded horses with body weight varying between 10 and 20%. RESULTS: The superficial body temperature (SBT) of the thoracolumbar region of the horse's back was imaged using a non-contact thermographic camera before and after riding under riders with LBW (low body weight, 10%) and HBW (high body weight, 15%). Images were analyzed using six methods: five recent SBT analyses and the novel approach based on Gray Level Co-Occurrence Matrix (GLCM) and Gray Level Run Length Matrix (GLRLM). Temperatures of the horse's thoracolumbar region were higher (p < 0.0001) after then before the training, and did not differ depending on the rider's body weight (p > 0.05), regardless of used SBT analysis method. Effort-dependent differences (p < 0.05) were noted for six features of GLCM and GLRLM analysis. The values of selected GLCM and GLRLM features also differed (p < 0.05) between the LBW and HBW groups. CONCLUSION: The GLCM and GLRLM analyses allowed the differentiation of horses subjected to a load of 10 and 15% of their body weights while horseback riding in contrast to the previously used SBT analysis methods. Both types of analyzing methods allow to differentiation thermal images obtained before and after riding. The textural analysis, including selected features of GLCM or GLRLM, seems to be promising tools in considering the quantitative assessment of thermographic images of horses' thoracolumbar region.


Assuntos
Dorso/fisiologia , Cavalos/fisiologia , Termografia/veterinária , Animais , Peso Corporal , Feminino , Humanos , Masculino , Condicionamento Físico Animal , Temperatura Cutânea
17.
Sensors (Basel) ; 22(1)2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-35009733

RESUMO

Infrared thermography (IRT) was applied as a potentially useful tool in the detection of pregnancy in equids, especially native or wildlife. IRT measures heat emission from the body surface, which increases with the progression of pregnancy as blood flow and metabolic activity in the uterine and fetal tissues increase. Conventional IRT imaging is promising; however, with specific limitations considered, this study aimed to develop novel digital processing methods for thermal images of pregnant mares to detect pregnancy earlier with higher accuracy. In the current study, 40 mares were divided into non-pregnant and pregnant groups and imaged using IRT. Thermal images were transformed into four color models (RGB, YUV, YIQ, HSB) and 10 color components were separated. From each color component, features of image texture were obtained using Histogram Statistics and Grey-Level Run-Length Matrix algorithms. The most informative color/feature combinations were selected for further investigation, and the accuracy of pregnancy detection was calculated. The image texture features in the RGB and YIQ color models reflecting increased heterogeneity of image texture seem to be applicable as potential indicators of pregnancy. Their application in IRT-based pregnancy detection in mares allows for earlier recognition of pregnant mares with higher accuracy than the conventional IRT imaging technique.


Assuntos
Algoritmos , Termografia , Animais , Feminino , Cavalos , Processamento de Imagem Assistida por Computador , Gravidez , Útero
18.
Int J Mol Sci ; 22(5)2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33671105

RESUMO

An adsorption process of magnetite nanoparticles functionalized with aminated chitosan (Fe3O4-AChit) showing application potential in nanomedicine into cell membrane models was studied. The cell membrane models were formed using a Langmuir technique from three selected phospholipids with different polar head-groups as well as length and carbon saturation of alkyl chains. The research presented in this work reveals the existence of membrane model composition-dependent regulation of phospholipid-nanoparticle interactions. The influence of the positively charged Fe3O4-AChit nanoparticles on a Langmuir film stability, phase state, and textures is much greater in the case of these formed by negatively charged 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) than those created by zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC). The adsorption kinetics recorded during penetration experiments show that this effect is caused by the strongest adsorption of the investigated nanoparticles into the DPPG monolayer driven very likely by the electrostatic attraction. The differences in the adsorption strength of the Fe3O4-AChit nanoparticles into the Langmuir films formed by the phosphatidylcholines were also observed. The nanoparticles adsorbed more easily into more loosely packed POPC monolayer.


Assuntos
Membrana Celular/química , Quitosana/química , Compostos Férricos/química , Nanomedicina , Nanopartículas/química , Fosfatidilcolinas/química , Fosfatidilgliceróis/química , Aminas/química , Animais , Humanos , Cinética , Modelos Biológicos , Propriedades de Superfície
19.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073072

RESUMO

Understanding the mechanism of interactions between magnetite nanoparticles and phospholipids that form cellular membranes at the molecular level is of crucial importance for their safe and effective application in medicine (e.g. magnetic resonance imaging, targeted drug delivery, and hyperthermia-based anticancer therapy). In these interactions, their surface coating plays a crucial role because even a small modification to its structure can cause significant changes to the behaviour of the magnetite nanoparticles that come in contact with a biomembrane. In this work, the influence of the magnetite nanoparticles functionalized with native and aminated starch on the thermodynamics, morphology, and dilatational elasticity of the model cell membranes was studied. The model cell membranes constituted the Langmuir monolayers formed at the air-water interface of dipalmitoylphosphatidylcholine (DPPC). The surface of the aminated starch-coated nanoparticles was enriched in highly reactive amino groups, which allowed more effective binding of drugs and biomolecules suitable for specific nano-bio applications. The studies indicated that the presence of these groups also reduced to some extent the disruptive effect of the magnetite nanoparticles on the model membranes and improved their adsorption.


Assuntos
1,2-Dipalmitoilfosfatidilcolina/química , Nanopartículas de Magnetita/química , Membranas Artificiais , Amido/química , Aminação , Propriedades de Superfície , Termodinâmica
20.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201648

RESUMO

The present study is devoted to the combined experimental and theoretical description of the photophysical properties and photodegradation of the new boron-dipyrromethene (BODIPY) derivatives obtained recently for biomedical applications, such as bacteria photoinactivation (Piskorz et al., Dyes and Pigments 2020, 178, 108322). Absorption and emission spectra for a wide group of solvents of different properties for the analyzed BODIPY derivatives were investigated in order to verify their suitability for photopharmacological applications. Additionally, the photostability of the analyzed systems were thoroughly determined. The exposition to the UV light was found first to cause the decrease in the most intensive absorption band and the appearance of the hypsochromically shifted band of similar intensity. On the basis of the chromatographic and computational study, this effect was assigned to the detachment of the iodine atoms from the BODIPY core. After longer exposition to UV light, photodegradation occurred, leading to the disappearance of the intensive absorption bands and the emergence of small intensity signals in the strongly blue-shifted range of the spectrum. Since the most intensive bands in original dyes are ascribed to the molecular core bearing the BF2 moiety, this result can be attributed to the significant cleavage of the BF2 ring. In order to fully characterize the obtained molecules, the comprehensive computational chemistry study was performed. The influence of the intermolecular interactions for their absorption in solution was analyzed. The theoretical data entirely support the experimental outcomes.


Assuntos
Compostos de Boro/química , Corantes Fluorescentes/química , Teoria da Densidade Funcional , Iodo/química , Conformação Molecular , Fotólise , Solventes/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA