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1.
Br J Dermatol ; 186(4): 713-720, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34783007

RESUMO

BACKGROUND: In xeroderma pigmentosum (XP), the main means of preventing skin and eye cancers is extreme protection against ultraviolet radiation (UVR). Protection is most important for the face. OBJECTIVES: We aimed to assess how well patients with XP adhere to medical advice to protect against UVR by objectively estimating the mean daily dose of UVR to the face. METHODS: We objectively estimated the UVR dose to the face in 36 patients with XP and 25 healthy individuals over 3 weeks in the summer. We used a new methodology which combined UVR dose measurements from a wrist-worn dosimeter with an activity diary record of face photoprotection behaviour for each 15-min period spent outside. A protection factor was associated with each behaviour, and the data were analysed using a negative binomial mixed-effects model. RESULTS: The mean daily UVR dose (weighted for DNA damage capacity) to the face in the patients with XP was 0·13 standard erythemal doses (SEDs) (mean in healthy individuals = 0·51 SED). There was wide variation between patients (range < 0·01-0·48 SED/day). Self-caring adult patients had a very similar UVR dose to the face as cared-for patients (0·13 vs. 0·12 SED/day), despite photoprotecting much more poorly when outside, because the self-caring adults were outside in daylight much less. CONCLUSIONS: Photoprotection behaviour varies widely within the XP group indicating that nonadherence to photoprotection advice is a significant issue. The timing and duration of going outside are as important as photoprotective measures taken when outside, to determine the UVR exposure to the face. This new methodology will be of value in identifying the sources of UVR exposure in other conditions in which facial UVR exposure is a key outcome, particularly in patients with multiple nonmelanoma skin cancers.


Assuntos
Neoplasias Cutâneas , Xeroderma Pigmentoso , Adulto , Face , Comportamentos Relacionados com a Saúde , Humanos , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/prevenção & controle , Raios Ultravioleta/efeitos adversos
2.
Insect Mol Biol ; 28(4): 455-472, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30652367

RESUMO

Gut microbiota research is an emerging field that improves our understanding of the ecological and functional dynamics of gut environments. The honey bee gut microbiota is a highly rewarding community to study, as honey bees are critical pollinators of many crops for human consumption and produce valuable commodities such as honey and wax. Most significantly, unique characteristics of the Apis mellifera gut habitat make it a valuable model system. This review discusses methods and pipelines used in the study of the gut microbiota of Ap. mellifera and closely related species for four main purposes: identifying microbiota taxonomy, characterizing microbiota genomes (microbiome), characterizing microbiota-microbiota interactions and identifying functions of the microbial community in the gut. The purpose of this contribution is to increase understanding of honey bee gut microbiota, to facilitate bee microbiota and microbiome research in general and to aid design of future experiments in this growing field.


Assuntos
Bactérias , Fenômenos Fisiológicos Bacterianos , Técnicas Bacteriológicas/métodos , Abelhas/microbiologia , Microbioma Gastrointestinal/fisiologia , Animais , Bactérias/classificação , Bactérias/genética , Entomologia/métodos , Microbioma Gastrointestinal/genética
3.
BJOG ; 122(1): 57-62, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24935560

RESUMO

BACKGROUND: Antenatal depression can have harmful consequences for the mother and fetus. Exercise may be a useful intervention to prevent and treat antenatal depression. OBJECTIVES: This systematic review aims to establish whether there is sufficient evidence to conclude that exercise is an effective intervention for preventing and treating antenatal depression. SEARCH STRATEGY: Searches using electronic databases from MEDLINE, Cochrane Library, CINAHL, EMBASE, AMED and PsycINFO were performed. SELECTION CRITERIA: Randomised controlled trials (RCT) that compared any type of exercise intervention with any comparator in pregnant women were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Meta-analysis was performed calculating standardised mean differences (SMD). MAIN RESULTS: Six trials (seven comparisons) were eligible for inclusion. Meta-analysis showed a significant reduction in depression scores (SMD -0.46, 95% CI -0.87 to -0.05, P = 0.03, I(2) = 68%) for exercise interventions relative to comparator groups. The test for subgroup differences in women who were non-depressed (one trial) (SMD -0.74, 95%CI -1.22 to -0.27, P = 0.002) and depressed (five trials) (SMD -0.41, 95% CI -0.88 to 0.07, P = 0.09) at baseline was not significant (P = 0.32). The test for subgroup differences between aerobic (one trial) and non-aerobic exercise (five trials) was also nonsignificant (P = 0.32). AUTHORS' CONCLUSIONS: We found some evidence that exercise may be effective in treating depression during pregnancy but this conclusion is based on a small number of low-moderate quality trials with significant heterogeneity and wide confidence intervals.


Assuntos
Depressão/prevenção & controle , Transtorno Depressivo/prevenção & controle , Terapia por Exercício/métodos , Complicações na Gravidez/prevenção & controle , Depressão/terapia , Transtorno Depressivo/terapia , Feminino , Humanos , Gravidez , Complicações na Gravidez/terapia , Resultado do Tratamento
4.
Biomacromolecules ; 15(1): 339-49, 2014 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-24299034

RESUMO

This study reports on the superior suitability of Polyhydroxybutyrate-polyethylene glycol hybrid polymers biosynthesised by Cupriavidus necator over PHB as biomaterials for tissue engineering. Incorporation of PEG106 (DEG) during PHB biosynthesis reduced crystallinity, molecular weight, and hydrophobicity while improving mechanical properties. In vitro olfactory ensheathing cell (OEC) proliferation was enhanced by cultivation on PHB-b-DEG films. Cultivation on PHB and PHB-b-DEG films showed no cytotoxic responses and cell viability and membrane integrity was sustained. PHB-b-DEG films promoted OECs entering into the DNA replication (S) phase and mitotic (G2-M) phase during the cell growth cycle and apoptosis was low. This study also confirmed an association between the level of neurite-outgrowth inhibitory protein (Nogo) and receptor pair Ig-like receptor B (PirB) expression and cell proliferation, both being down-regulated in cells grown on hybrid films when compared with PHB and asynchronous growth. Thus, DEG-terminated PHB-based biomaterials have great potential as biological scaffolds supporting nerve repair.


Assuntos
Movimento Celular/fisiologia , Sobrevivência Celular/fisiologia , Hidroxibutiratos/química , Neurônios/fisiologia , Polietilenoglicóis/química , Animais , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cupriavidus necator , Hidroxibutiratos/farmacologia , Neurônios/efeitos dos fármacos , Polietilenoglicóis/farmacologia , Polímeros/química , Polímeros/farmacologia , Difração de Raios X
5.
Biomacromolecules ; 15(2): 644-9, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24364695

RESUMO

Infrared (IR) microspectroscopy has the capacity to determine the extent of phase separation in polymer blends. However, a major limitation in the use of this technique has been its reliance on overlapping peaks in the IR spectra to differentiate between polymers of similar chemical compositions in blends. The objective of this study was to evaluate the suitability of deuteration of one mixture component to separate infrared (IR) absorption bands and provide image contrast in phase separated materials. Deuteration of poly(3-hydroxyoctanoate) (PHO) was achieved via microbial biosynthesis using deuterated substrates, and the characteristic C-D stretching vibrations provided distinct signals completely separated from the C-H signals of protonated poly(3-hydroxybutyrate) (PHB). Phase separation was observed in 50:50 (% w/w) blends as domains up to 100 µm through the film cross sections, consistent with earlier reports of phase separation observed by scanning electron microscopy (SEM) of freeze-fractured protonated polymer blends. The presence of deuterated phases throughout the film suggests there is some miscibility at smaller length scales, which increased with increasing PHB content. These investigations indicate that biodeuteration combined with IR microspectroscopy represents a useful tool for mapping the phase behavior of polymer blends.


Assuntos
Polímeros/química , Espectroscopia de Ressonância Magnética , Conformação Molecular , Espectrofotometria Infravermelho
6.
Dis Esophagus ; 27(5): 485-92, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23082947

RESUMO

Epithelial to mesenchymal transition (EMT) promotes tumor progression and invasion. As no study has focused on gastroesophageal junction (GEJ) tumors, the expression of three EMT-related proteins (S100A4, vimentin, and Snail1) was investigated with the aim of assessing their pathologic and prognostic significance. Resection specimens were obtained from 104 patients who underwent surgery for GEJ adenocarcinoma, without preoperative chemotherapy. Three tissue cores were obtained from each of the tumor body (TB), luminal surface (LS), and invasive edge (IE) to produce tissue microarrays, and immunohistochemical staining was performed. The microarrays were scored independently by two observers. The demographic and histopathologic details of the patients were collected. Overall positive expression was observed in 88 (S100A4, 85%), 16 (vimentin, 14%), and 92 (Snail1, 89%) tumors. Staining for S100 A4 was positive in 79 (76%) of TB, 69 (66%) of IE, and 69 (66%) of LS specimens. Staining for vimentin was positive in 7 (6%) of TB, 11 (11%) of IE, and 5 (5%) of LS specimens. Staining for Snail1 was positive in 83 (80%) of TB, 51 (49%) of IE, and 78 (75%) of LS specimens. Positive staining of TB for S100A4 (P = 0.04) and Snail1 at IE (P = 0.01) was associated with involvement of circumferential resection margins. Positive staining for S100A4 in the TB (P = 0.02) and LS (P = 0.01) was associated with poor 5-year overall survival. Vimentin had no statistically significant relationships with pathologic factors or outcome. The acquisition of mesenchymal protein S100A4 is associated with a poor prognosis in patients with GEJ tumors who undergo potentially curative surgery, and LS samples can be used to obtain prognostic information. Increased EMT-related protein expression (S100A4, Snail1) is associated with the involvement of circumferential resection margin.


Assuntos
Neoplasias Esofágicas/metabolismo , Junção Esofagogástrica/patologia , Proteínas S100/metabolismo , Fatores de Transcrição/metabolismo , Vimentina/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Idoso , Biomarcadores Tumorais/metabolismo , Transição Epitelial-Mesenquimal , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Feminino , Humanos , Masculino , Prognóstico , Proteína A4 de Ligação a Cálcio da Família S100 , Fatores de Transcrição da Família Snail , Coloração e Rotulagem
7.
Gut Microbes ; 16(1): 2308049, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38299318

RESUMO

Infectious diarrheal diseases are the third leading cause of mortality in young children, many of which are driven by Gram-negative bacterial pathogens. To establish successful host infections these pathogens employ a plethora of virulence factors necessary to compete with the resident microbiota, and evade and subvert the host defenses. The type II secretion system (T2SS) is one such conserved molecular machine that allows for the delivery of effector proteins into the extracellular milieu. To explore the role of the T2SS during natural host infection, we used Citrobacter rodentium, a murine enteric pathogen, as a model of human intestinal disease caused by pathogenic Escherichia coli such as Enteropathogenic and Enterohemorrhagic E. coli (EPEC and EHEC). In this study, we determined that the C. rodentium genome encodes one T2SS and 22 potential T2SS-secreted protein effectors, as predicted via sequence homology. We demonstrated that this system was functional in vitro, identifying a role in intestinal mucin degradation allowing for its utilization as a carbon source, and promoting C. rodentium attachment to a mucus-producing colon cell line. During host infection, loss of the T2SS or associated effectors led to a significant colonization defect and lack of systemic spread. In mice susceptible to lethal infection, T2SS-deficient C. rodentium was strongly attenuated, resulting in reduced morbidity and mortality in infected hosts. Together these data highlight the important role of the T2SS and its effector repertoire during C. rodentium pathogenesis, aiding in successful host mucosal colonization.


Assuntos
Infecções por Enterobacteriaceae , Escherichia coli Êntero-Hemorrágica , Microbioma Gastrointestinal , Sistemas de Secreção Tipo II , Criança , Humanos , Animais , Camundongos , Pré-Escolar , Citrobacter rodentium/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Infecções por Enterobacteriaceae/microbiologia
8.
Int J Immunogenet ; 40(4): 322-3, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23107280

RESUMO

HLA-DQB1*06:48 has single nucleotide polymorphisms within codons 70 and 62 of exon 2 (GGG>AGG and AAG>AAC) relative to HLA-DQB1*06:02:01 and HLA-DQB1*06:37. This results in amino acid differences (G>R and K>N) that will change the polarity and charge of the encoded antigen and may therefore affect its peptide repertoire.


Assuntos
Cadeias beta de HLA-DQ/genética , Alelos , Substituição de Aminoácidos , Povo Asiático , Sequência de Bases , Variação Genética , Teste de Histocompatibilidade , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA
9.
Int J Immunogenet ; 40(6): 453-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23724946

RESUMO

Accurate human leucocyte antigen (HLA) typing results are essential in determining the degree of compatibility between donor and recipient in both solid organ (SO) and hematopoietic stem cell (HSC) transplantation. Current HLA typing methodologies can generate ambiguous results which may need resolving. This group-specific sequencing approach allowed investigation into the presence of the low expressor HLA-A*24:02:01:02L allele and the rare HLA-A*02:64 allele in a SO transplant recipient and a HSC transplant recipient, respectively. Locus-specific amplification of HLA-A was performed. Exons 2 and 3 were sequenced in both directions followed by group-specific sequencing to resolve ambiguities. Hemizygous sequence data of intron 2 generated from the HLA-A*24 allele indicated the presence of the HLA-A*24:02:01:01 allele. HLA-A*02:64 was identified by sequencing the allele in isolation over exons 2 and 3 and allowed confirmation of this allele sequence with the IMGT/HLA database (Accession number AY297166). This approach is cost efficient and can be modified to sequence alleles at other HLA loci. It has also been adapted to characterize the novel HLA-DQB1*06:48 allele (Accession number HE647646) as well as the non-HLA gene, UGT2B17, making it a useful tool to augment existing typing methodologies.


Assuntos
Alelos , Antígenos HLA/genética , Teste de Histocompatibilidade/métodos , Análise de Sequência de DNA/métodos , Sequência de Bases , Primers do DNA/genética , Éxons/genética , Genótipo , Antígeno HLA-A24/genética , Cadeias beta de HLA-DQ/genética , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Dados de Sequência Molecular , Transplante de Órgãos/métodos , Reação em Cadeia da Polimerase/métodos , Polimorfismo Genético , Reprodutibilidade dos Testes , Homologia de Sequência do Ácido Nucleico , Doadores de Tecidos
10.
Int J Immunogenet ; 40(2): 116-9, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22726315

RESUMO

Acute graft versus host disease (aGvHD) is a major cause of early morbidity post-haematopoietic stem cell transplantation with minor histocompatibility antigens being a contributing factor. One mHA encoded by the UDP glycosyltransferase 2 family polypeptide B17 (UGT2B17) gene has been shown to be immunogenic because of differential expression in the donor and recipient. We investigated the effects of a homozygous gene deletion of UGT2B17 on the severity of acute aGvHD post-HSCT in HLA-matched related donors. 115 donor and recipient HLA and UGT2B17 genotypes were determined using PCR-SSO and PCR-SSP, respectively. aGvHD grading was determined using routine criteria and dichotomized into either nonclinically significant (0-I) or clinically significant (II-IV). For all analyses, P-values of ≤ 0.05 were considered significant. The frequency of the gene deletion within the total cohort tested was 29.1%. A significant increase in aGvHD severity (grades II-IV) was seen in UGT2B17 recipients expressing the protein when transplanted with a UGT2B17 disparate donor (P = 0.011). We observed a significant association between UGT2B17 expressing recipients and UGT2B17 deficient donors with the severity of aGvHD. This study provides additional evidence that genomic variations may predispose to more severe aGvHD, but are not a mechanism for GvHD.


Assuntos
Deleção de Genes , Glucuronosiltransferase/genética , Glucuronosiltransferase/imunologia , Doença Enxerto-Hospedeiro/genética , Doença Enxerto-Hospedeiro/imunologia , Transplante de Células-Tronco Hematopoéticas , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Genótipo , Antígeno HLA-A2/genética , Antígeno HLA-A2/imunologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Antígenos de Histocompatibilidade Menor/genética , Oligopeptídeos/genética , Adulto Jovem
11.
Br J Cancer ; 107(8): 1257-67, 2012 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-23047592

RESUMO

BACKGROUND: The National Epirubicin Adjuvant Trial (NEAT) and BR9601 trials tested the benefit of epirubicin when added to cyclophosphamide, methotrexate and 5-fluorouracil (E-CMF) compared with standard CMF in adjuvant chemotherapy for women with early breast cancer. This report details longer follow-up with interesting additional time-dependent analyses. METHODS: National Epirubicin Adjuvant Trial used epirubicin (E) 3-weekly for four cycles followed by classical (c) CMF for four cycles (E-CMF) compared with cCMF for six cycles. BR9601 used E 3-weekly for four cycles followed by CMF 3-weekly for four cycles, compared with CMF 3-weekly for eight cycles. RESULTS: In all, 2391 eligible patients were randomised and with a median 7.4-year follow-up, E-CMF confirmed a significant benefit over CMF in both relapse-free survival (RFS) (78% vs 71% 5 years RFS, respectively, hazard ratio (HR)=0.75 (95% CI: 0.65-0.86), P<0.0001) and overall survival (OS) (84% vs 78% 5 years OS, respectively, HR=0.76 (95% CI: 0.65-0.89), P=0.0007). Interaction of treatment effect and prognostic factors was demonstrated for duplication of chromosome 17 centromeric enumeration (Ch17CEP) as previously reported. Poor prognostic factors at diagnosis (ER and PR negative and HER2 positive) showed time-dependent annual hazard rates for RFS and OS. In univariate analysis, these factors demonstrated more favourable HRs for RFS after 5 years. Treatment effects also suggested a differential benefit for E-CMF within the first 5 years for poor prognosis tumours. CONCLUSION: Longer follow-up has confirmed E-CMF as significantly superior to CMF for all patients. Ch17CEP duplication was the only biomarker that demonstrated significant treatment interaction. Standard poor prognostic factors at diagnosis were time-dependent, and after 5 years disease-free, poor prognosis patients demonstrated favourable HRs for survival.


Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Epirubicina/administração & dosagem , Adesão à Medicação , Idoso , Neoplasias da Mama/patologia , Quimioterapia Adjuvante , Ciclofosfamida/administração & dosagem , Feminino , Fluoruracila/administração & dosagem , Seguimentos , Humanos , Metotrexato/administração & dosagem , Pessoa de Meia-Idade
12.
Lasers Surg Med ; 43(6): 490-8, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21761419

RESUMO

BACKGROUND AND OBJECTIVES: To demonstrate the feasibility of a novel, thin film, laser-activated adhesive in sealing penetrative corneal wounds with a view to replacing sutures in ophthalmic operations. METHODS: A previously described thin film adhesive composed of chitosan and indocyanine green activated by infrared laser (808 nm) was used to seal penetrating corneal wounds ranging from 1 to 6 mm in size in enucleated bovine eyes. The excised corneas were subjected to pressure tests to evaluate the strength of the corneal repairs and compared to sutures and commercial fibrin glue, Tisseel®. Temperatures at the adhesive-tissue interface were measured and histological examinations of the repairs performed to investigate potential tissue damage. Biodegradability of the films was monitored in lysozyme solutions at concentrations reported in tears. RESULTS: The adhesive effectively sealed corneal wounds, withstanding pressures of 140-320 mmHg, far in excess of the normal intraocular pressure. In contrast, pressures of 40-80 mm Hg were determined using a combination of sutures with Tisseel® as a sealant. The laser-activation process was 1.5-5 times faster than other procedures studied and required no curing time. A transient, mean temperature of 56 ± 2°C was measured at the adhesive-tissue interface while histology showed no tissue damage as a consequence of the irradiation process. Irradiation had no significant influence on adhesive biodegradation in vitro, which lost approximately 30% of their initial weight in a lysozyme solution (6 mg ml(-1)). CONCLUSIONS: The thin film adhesive was found to be an effective in sealing corneal wounds with considerable advantages over sutures, including speed of application and sealing strength and biodegradability.


Assuntos
Quitosana , Lesões da Córnea , Perfuração da Córnea/terapia , Verde de Indocianina , Terapia a Laser , Adesivos Teciduais , Animais , Bovinos , Estudos de Viabilidade
13.
Biotechnol Lett ; 33(2): 417-21, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20953663

RESUMO

Chitosan is a promising biomaterial for biomedical applications and is currently applied as wound dressings. While chitosan solutions demonstrate strong bactericidal activity against a range of medically important bacteria, the study here reports a loss of this beneficial property in thin films cast from the same solutions. Chitosan films (20 microm) showed no inhibitory effects against Escherichia coli, Staphylococcus aureus or S. epidermidis species. In contrast, solutions used to prepare the films showed almost complete inhibition (approximately 98 ± 2%) when tested on bacterial lawns and in liquid cultures. Increased acidity of the chitosan solutions (pH 5) was shown to promote the bactericidal effects of this biopolymer. The concept that devices fabricated from chitosan have an inherent antimicrobial activity is suggested as an important misconception.


Assuntos
Anti-Infecciosos/farmacologia , Quitosana/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Quitosana/química , Concentração de Íons de Hidrogênio , Viabilidade Microbiana/efeitos dos fármacos
14.
Insect Mol Biol ; 19(5): 653-8, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20546039

RESUMO

Honey bees (Apis mellifera L.) play a vital role in agriculture as pollinators, and serve as model organisms of social behaviour and immunity. The lack of both immortalized cell lines and methods to introduce recombinant DNA reliably into primary cells hinders cellular and molecular studies in this organism. We hereby demonstrate the expression of a GFP gene delivered by lentivirus transduction to cultured embryonic cells. The success of this approach indicates that viral transduction could be used to deliver constitutively active oncogenes in order to immortalize honey bee cells. We were able to revive cells successfully after several months of cryogenic storage and we show how the proteome varies between freshly collected and cultured embryonic cells.


Assuntos
Abelhas/química , Abelhas/genética , Proteínas de Insetos/análise , Proteoma/análise , Transdução Genética/veterinária , Animais , Células Cultivadas , Expressão Gênica , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Proteínas de Insetos/genética , Lentivirus/genética , Transdução Genética/métodos , Transgenes
15.
Biomacromolecules ; 11(10): 2707-15, 2010 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-20849100

RESUMO

Poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are biopolyesters reported to provide favorable microenvironments for cell culture and possess potential for tissue engineering applications. Both biopolymers have been investigated for applications in a variety of medical scenarios, including nerve and bone repair. This study investigated the influence these biomaterials exerted on cell cycle progression of olfactory ensheathing cells (OECs) and mesenchymal stem cells (MSCs) commonly used in the engineering of nerve and bone tissues. Cell cycle regulation is important for cell survival; analysis revealed that the biomaterials induced significant cell cycle progression in both MSCs and OECs. Significantly higher percentages of cells were cycled at synthesis (S) phase of the cycle on PHBV films compared to PHB, with MSCs more susceptible than OECs. Furthermore, detection of early stages of apoptotic activation showed significant differences in the two cell populations exhibiting necrosis and apoptosis when cultivated on the biomaterials. OECs compromised on PHB (5.6%) and PHBV (2.5%) compared to MSCs with 12.6% on PHB and 17% on PHBV. Significant differences in crystallinity and surface rugosity were determined between films of the two biomaterials, 88% and 1.12 µm for PHB and 76% and 0.72 µm for PHBV. While changes in surface properties may have influenced cell adhesion, the work presented here suggests that application of these biomaterials in tissue engineering are specific to cell type and requires a detailed investigation at the cell-material interface.


Assuntos
Materiais Biocompatíveis/síntese química , Ciclo Celular , Hidroxibutiratos/química , Células-Tronco Mesenquimais/citologia , Células-Tronco Neurais/citologia , Poliésteres/química , Engenharia Tecidual/métodos , Animais , Apoptose/efeitos dos fármacos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem da Célula/efeitos dos fármacos , Células Cultivadas , DNA/metabolismo , Fenômenos Mecânicos , Células-Tronco Mesenquimais/metabolismo , Microscopia Confocal , Microscopia Eletrônica de Varredura , Células-Tronco Neurais/metabolismo , Mucosa Olfatória/citologia , Mucosa Olfatória/metabolismo , Propriedades de Superfície
16.
Biomacromolecules ; 11(12): 3563-70, 2010 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-21080623

RESUMO

We have used laser irradiation to enhance the natural adhesiveness of chitosan to form a thin film surgical adhesive. Prevention of infection at surgical sites often utilizes systemic provision of antibiotics with reduced local efficacy and potential side effects. In the work reported here, we investigate the bactericidal properties of laser-irradiated chitosan films and their impregnation with the antibiotic vancomycin. Despite strong efficacy in solution, chitosan films showed no antimicrobial activity against representatives of common pathogens Escherichia coli , Staphylococcus aureus , and S. epidermidis . In contrast, a composite of chitosan adhesive and the antibiotic vancomycin showed therapeutically significant release profiles greater that the Minimum Bactericidal Concentrations (MBCs) for the Staphylococci over a 28 day period. These composite films had greater crystallinity, up to 28 ± 3 compared to 8.9 ± 2%, for its unblended counterpart. Despite a significant increase in material strength from 31.4 ± 4 to 77.5 ± 5 MPa, flexibility was still maintained with an elongation to break around 5 ± 2% and fold endurance of approximately 30 ± 3-folds. Laser irradiation had no apparent effect on the release or activity of the antibiotic which survived transient temperatures at the film-tissue interface during infrared irradiation of around 54 °C. Furthermore, significant adhesive strength was still apparent, 15.6 ± 2 KPa. Thus, we have developed a laser-activated bioadhesive with the potential to close wounds while facilitating the prevention of microbial infection through local release of antibiotic targeted to the site of potential infection.


Assuntos
Antibacterianos/química , Materiais Biocompatíveis/uso terapêutico , Quitosana/uso terapêutico , Adesivos Teciduais/química , Vancomicina/uso terapêutico , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Controle de Infecções , Lasers , Testes de Sensibilidade Microbiana , Temperatura , Cicatrização
17.
Nurse Educ Pract ; 43: 102697, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31981971

RESUMO

It is important to evaluate stakeholder feedback regarding any change to a clinical supervision model to maintain quality. The Quality Practical Experience (QPE) instruments offer both the nurse on the ward involved with supervising student learning and the student nurse the opportunity to evaluate their satisfaction with the supervision model. This paper reports on the evaluation of the construct validity and the reliability of the QPE instruments measuring nurse and nursing student satisfaction with the clinical supervision model. Methodological design for the reliability and validation of a measuring instrument. The nurse and the student QPE instruments were tested with convenience samples of 488 nurses and 1116 student nurses, respectively. Psychometric tests included internal reliability, test-retest reliability and factor analyses. Exploratory factor analysis for both QPEs supported a three-factor solution; the nurse QPE explained 48% and student nurse QPE 45% of variance. Internal reliability and test-retest reliability were stable over time (nurse QPE ICC = 0.82; student nurse QPE ICC = 0.71). Both QPE instruments were found to be valid and reliable. Feedback from all stakeholders involved with supporting student nurses during clinical placement is important.

18.
J Contemp Brachytherapy ; 12(6): 586-592, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33437307

RESUMO

PURPOSE: AccuBoost is a complex non-invasive brachytherapy procedure for breast treatment. This technique requires a radiation oncologist to manually select applicator grid position and size by overlaying transparencies over a mammographic image to encompass surgical clips and resected tumor bed. An algorithm was developed in MATLAB™ to automate the selection of round applicators based on surgical clip position. MATERIAL AND METHODS: A total of 42 mammograms belonging to 10 patients were retrospectively analyzed. Images were pre-processed by masking imprinted localization grid and regions around the grid. A threshold was applied to isolate high-intensity pixels and generate a binary image. A set of morphological operations including region dilation, filling, clearing border structures, and erosion were performed to segment the different regions. A support vector machine classification model was trained to categorize segmented regions as either surgical clips or miscellaneous objects based on different region properties (area, perimeter, eccentricity, circularity, minor axis length, and intensity-derived quantities). Applicator center position was determined by calculating the centroid of detected clips. Size of the applicator was determined with the smallest circle that encompassed all clips with an isotropic 1.0 cm margin. RESULTS: The clip identification model classified 946 regions, with a sensitivity of 96.6% and a specificity of 98.2%. Applicator position was correctly predicted for 20 of 42 fractions and was within 0.5 cm of physician-selected position for 33 of 42 fractions. Applicator size was correctly predicted for 25 out of 42 fractions. CONCLUSIONS: The proposed algorithm provided a method to quantitatively determine applicator position and size for AccuBoost treatments, and may serve as a tool for independent verifications. The discrepancy between physician-selected and algorithm-predicted determinations of applicator position and size suggests that the methodology may be further improved by considering radiomic features of breast tissue in addition to clip position.

19.
Chronic Dis Can ; 29(2): 70-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19281692

RESUMO

Provincial and regional decision makers in the injury prevention field were interviewed in British Columbia (B.C.) to obtain their views about best processes for the transfer or dissemination of relevant data. These decision makers (n = 13) indicated that data should provide them with a holistic and comprehensive picture to support their decision processes. In addition, they felt information about injury types and rates should be linked backward to determinants or causes and forward to consequences or outcomes. This complete chain of data is needed for planning and evaluating health promotion interventions. It was also felt that data providers needed to devote more effort to fostering effective receptor capacity, so that injury prevention professionals will be better able to understand, interpret and apply the data. These findings can likely be generalized to other jurisdictions and policy areas, and offer additional insight into the practicalities of knowledge transfer and exchange in researcher/decision maker partnerships.


Assuntos
Atitude do Pessoal de Saúde , Administradores de Instituições de Saúde/psicologia , Disseminação de Informação/métodos , Diretores Médicos/psicologia , Regionalização da Saúde/organização & administração , Ferimentos e Lesões/epidemiologia , Pessoal Administrativo , Colúmbia Britânica/epidemiologia , Causalidade , Efeitos Psicossociais da Doença , Tomada de Decisões Gerenciais , Difusão de Inovações , Pessoas com Deficiência/estatística & dados numéricos , Feminino , Administradores de Instituições de Saúde/educação , Administradores de Instituições de Saúde/organização & administração , Política de Saúde , Promoção da Saúde , Necessidades e Demandas de Serviços de Saúde , Humanos , Masculino , Programas Nacionais de Saúde/organização & administração , Diretores Médicos/educação , Diretores Médicos/organização & administração , Vigilância da População , Desenvolvimento de Programas , Inquéritos e Questionários , Ferimentos e Lesões/etiologia , Ferimentos e Lesões/prevenção & controle
20.
Biomacromolecules ; 9(1): 314-20, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18067255

RESUMO

Small-angle neutron scattering was used to probe the molecular conformation of various polyhydroxyalkanoates (PHAs) and their bioPEGylated counterparts (PHA- b-PEG). Analysis of neutron scattering profiles of these polymers dissolved in deuterated chloroform at various concentrations from dilute (approximately 0.1% w/v) to semidilute (approximately 7% w/v) showed the two distinct regimes and established overlap concentrations around 4-9 mg mL(-1). Scattering profiles were similar for all polymers investigated; power laws of approximately Q(-1.66) at high Q demonstrated that chloroform behaves as a good solvent for PHAs and suggests that under conditions synonymous with processing the solvated chains were swollen rather than in Gaussian conformation as previously reported. A gradual change to Guinier knees was followed by slopes of Q(-3) suggesting the presence of supramolecular structures at larger length scales. These observations in both the dilute and semidilute concentrations have not been previously reported. Zimm analysis of the data provided gyration radii and absolute molecular weights consistent with trends established using light scattering but showed some variation in their second virial coefficients. While natural-synthetic hybrids of PHA- b-PEG can self-assemble into microporous films, they showed no noticeable differences in chain conformation when in solution, the fabricating medium. This suggests that some form of entropic inducement is required.


Assuntos
Alcanos/química , Polietilenoglicóis/química , Nêutrons , Espalhamento de Radiação , Soluções
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