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1.
Sex Reprod Healthc ; 39: 100950, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38335840

RESUMO

OBJECTIVE: Young people are prioritized regarding the promotion and safeguarding of sexual and reproductive health and rights - SRHR. In Sweden, the school is seen as an important arena with members of the school health-care or SHC team as vital actors in this work. This study explored SRHR-related work in SHC teams in Sweden. METHODS: Within an explorative qualitative design, structured interviews were conducted with 33 nurses, counsellors, SHC unit managers and headmasters. Reflexive thematic analysis was applied, and two main themes found. RESULTS: SHC team members see SRHR as an urgent topic, but address it only 'when necessary', not systematically - and they experience a shortage of guidance and cooperation regarding SRHR-related work. Even in a country with agreement on the importance of SRHR for all and on providing holistic comprehensive sex education in schools, young people are left to chance - i.e., to the SRHR competence in the professionals they meet. CONCLUSION: SHC team members in Sweden see SRHR as an urgent topic but do not address it systematically. Moreover, they experience a shortage of guidance for their work. To avoid any professional stress of conscience and for equitable school health care regarding SRHR to be realized, research-informed policy needs to underline systematic, comparable and proactive practice.


Assuntos
Serviços de Saúde Reprodutiva , Saúde Reprodutiva , Humanos , Adolescente , Comportamento Sexual , Direitos Sexuais e Reprodutivos , Equipe de Assistência ao Paciente
2.
PLoS One ; 18(6): e0287041, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37294750

RESUMO

Pig production has a short history in Uganda. The majority of pigs are kept by smallholder farmers in rural areas where access to veterinary services is limited, and pig keeping has been suggested as a potential pathway out of poverty for smallholders. Previous research has identified the disease of African swine fever (ASF) as a major threat, causing high mortalities in pigs. With no available cure or vaccine, the only option is to implement biosecurity measures, i.e. strategies that prevent the spread of ASF. This paper draws on data from four months of ethnographic fieldwork in rural northern Uganda. Combining methods of participant observation, semi-structured interviews, focus group discussions and a survey, the aim was to improve understanding of smallholders' perceptions and responses to pig health issues such as ASF. Applying the concept of practical knowledge, this paper analyses the potential and limitations of smallholders' practice-based knowledge as a means of dealing with pig health issues. The results show that while pigs were appreciated locally for providing an income, many informants found it difficult to deal with pig diseases effectively. Consequently, informants commonly expressed a need for other kinds of knowledge in their pig production, indicating that veterinary advice can play an important role in reducing the negative impact of pig health issues. For animal health provision to have relevance in this context, however, veterinary practitioners must pay close attention to smallholders' priorities and ways of knowing in their livestock keeping. Results further show that pig health issues made some informants abandon pig production altogether. To enhance the potential of pig production as a poverty mitigation strategy in Uganda, research and policy need to focus on ways of bettering general conditions for smallholder pig keeping, including improving the quality of and access to veterinary services in rural areas.


Assuntos
Febre Suína Africana , Suínos , Animais , Humanos , Febre Suína Africana/prevenção & controle , Uganda , Criação de Animais Domésticos/métodos , Conhecimentos, Atitudes e Prática em Saúde , Gado
3.
Front Plant Sci ; 14: 1114408, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36998689

RESUMO

The cultivation of vining pea (Pisum sativum) faces a major constraint with root rot diseases, caused by a complex of soil-borne pathogens including the oomycetes Aphanomyces euteiches and Phytophtora pisi. Disease resistant commercial varieties are lacking but the landrace PI180693 is used as a source of partial resistance in ongoing pea breeding programs. In this study, the level of resistance and their interaction with A. euteiches virulence levels of six new back-crossed pea breeding lines, deriving from the cross between the susceptible commercial cultivar Linnea and PI180693, were evaluated for their resistance towards aphanomyces root rot in growth chamber and green house tests. Resistance towards mixed infections by A. euteiches and P. pisi and commercial production traits were evaluated in field trials. In growth chamber trials, pathogen virulence levels had a significant effect on plant resistance, as resistance was more consistent against A. euteiches strains exhibiting high or intermediate virulence compared with lowly virulent strains. In fact, line Z1701-1 showed to be significantly more resistant than both parents when inoculated with a lowly virulent strain. In two separate field trials in 2020, all six breeding lines performed equally well as the resistant parent PI180693 at sites only containing A. euteiches, as there were no differences in disease index. In mixed infections, PI180693 exhibited significantly lower disease index scores than Linnea. However, breeding lines displayed higher disease index scores compared with PI180693, indicating higher susceptibility towards P. pisi. Data on seedling emergence from the same field trials suggested that PI180693 was particularly sensitive towards seed decay/damping off disease caused by P. pisi. Furthermore, the breeding lines performed equally well as Linnea in traits important for green pea production, again emphasizing the commercial potential. In summary, we show that the resistance from PI180693 interacts with virulence levels of the pathogen A. euteiches and is less effective towards root rot caused by P. pisi. Our results show the potential use of combining PI180693 partial resistance against aphanomyces root rot with commercially favorable breeding traits in commercial breeding programs.

4.
J Wound Care ; 31(6): 502-509, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35678791

RESUMO

OBJECTIVE: Endotoxin causes inflammation and can impair wound healing. Conventional methods that reduce bioburden in wounds by killing microorganisms using antibiotics, topical antimicrobials or antimicrobial dressings may induce endotoxin release from Gram-negative bacteria. Another approach is to reduce bioburden by adsorbing microorganisms, without killing them, using dialkylcarbamoyl chloride (DACC)-coated wound dressings. This study evaluated the endotoxin-binding ability of a DACC-coated wound dressing (Sorbact Compress, Abigo Medical AB, Sweden) in vitro, including its effect on the level of natural endotoxin released from Gram-negative bacteria. METHOD: Different concentrations of purified Pseudomonas aeruginosa endotoxin and a DACC-coated dressing were incubated at 37°C for various durations. After incubation, the dressing was removed and endotoxin concentration in the solution was quantified using a Limulus amebocyte lysate (LAL) assay. The DACC-coated dressing was also incubated with Pseudomonas aeruginosa cells for one hour at 37°C. After incubation, the dressing and bacterial cells were removed and shed endotoxin remaining in the solution was quantified. RESULTS: Overnight incubation of the DACC-coated wound dressing with various concentrations of purified Pseudomonas aeruginosa endotoxin (96-11000 EU/ml) consistently and significantly reduced levels of free endotoxin by 93-99% (p<0.0001). A significant endotoxin reduction of 39% (p<0.001) was observed after five minutes. The DACC-coated dressing incubated with clinically relevant Pseudomonas aeruginosa cells also reduced shed endotoxin by >99.95% (p<0.0001). CONCLUSION: In this study, we showed that a DACC-coated wound dressing efficiently and rapidly binds both purified and shed endotoxin from Pseudomonas aeruginosa in vitro. This ability to remove both endotoxin and bacterial cells could promote the wound healing process.


Assuntos
Anti-Infecciosos Locais , Infecção dos Ferimentos , Antibacterianos/farmacologia , Bandagens/microbiologia , Cloretos , Endotoxinas , Humanos , Pseudomonas aeruginosa , Cicatrização , Infecção dos Ferimentos/prevenção & controle
5.
Front Vet Sci ; 9: 773903, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35359673

RESUMO

People in northern Uganda are currently rebuilding their lives after a lengthy period of conflict. To facilitate this, the Ugandan government and donors have promoted investment in pigs as an important strategy for generating income quickly and ensuring livelihood security. In this context, animal health issues are an acknowledged challenge, creating uncertainty for animal owners who risk losing both their animals and income. This paper draws on policy documents guiding the veterinary sector, interviews with faculty staff at Makerere University and with veterinarians and paraprofessionals in northern Uganda, and ethnographic fieldwork in smallholder communities. The aims of this study were to contribute to an understanding of the structure of veterinary support and its dominant development narratives in policy and veterinary education and of the way in which dominant discourses and practices affect smallholders' ability to treat sick animals. Particular attention was paid to the role of paraprofessionals, here referring to actors with varied levels of training who provide animal health services mainly in rural areas. The results suggest that veterinary researchers, field veterinarians and government officials in agricultural policy share a common discourse in which making smallholders more business-minded and commercializing smallholder production are important elements in reducing rural poverty in Uganda. This way of framing smallholder livestock production overlooks other important challenges faced by smallholders in their livestock production, as well as alternative views of agricultural development. The public veterinary sector is massively under-resourced; thus while inadequately trained paraprofessionals and insufficient veterinary support currently present a risks to animal health, paraprofessionals fulfill an important role for smallholders unable to access the public veterinary sector. The dominant discourse framing paraprofessionals as "quacks" tends to downplay how important they are to smallholders by mainly highlighting the negative outcomes for animal healthcare resulting from their lack of formalized training. The conclusions of this study are that both animal health and smallholders' livelihoods would benefit from closer collaboration between veterinarians and paraprofessionals and from a better understanding of smallholders' needs.

6.
J Mater Sci Mater Med ; 33(2): 22, 2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35133505

RESUMO

Wound dressings that exert an antimicrobial effect in order to prevent and treat wound infections can be harmful to the wound healing process. Dressings with hydrophobic coatings, however, have been suggested to both reduce the microbial load and promote the healing process. Therefore, the potential effects of a dialkylcarbamoyl chloride (DACC)-coated dressing on fibroblasts and keratinocytes in wound healing were studied using mechanical scratch wounding of confluent cell layers as an in vitro model. Additionally, gene expression analysis by qRT-PCR was used to elucidate the longitudinal effects of the DACC-coated dressing on cell responses, specifically inflammation, growth factor induction and collagen synthesis. DACC promoted cell viability, did not stick to the cell layers, and supported normal wound healing progression in vitro. In contrast, cells became attached to the uncoated reference material, which inhibited scratch closure. Moreover, DACC slightly induced KGF, VEGF, and GM-CSF expression in HaCaT cells and NHDF. Physiological COL1A1 and COL3A1 gene expression by NHDF was observed under DACC treatment with no observable effect on S100A7 and RNASE7 levels in HaCaT cells. Overall, the DACC coating was found to be safe and may positively influence the wound healing outcome. Graphical abstract.


Assuntos
Bandagens , Cloretos , Cloretos/farmacologia , Fibroblastos , Queratinócitos , Cicatrização
7.
Reprod Biomed Soc Online ; 8: 23-31, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30911689

RESUMO

This study sought to explore how Swedish parents who had commissioned surrogacy abroad experienced the process of parenthood recognition. The study consisted of in-depth interviews with five couples and 10 individuals representing 10 additional couples who had used surrogacy abroad, mainly in India. The construction of motherhood and fatherhood in the Swedish system contradicts how parenthood is defined in the surrogacy process. This study found that the formal recognition of parenthood involved a complex and frustrating process where the presumption of fatherhood and step-child adoption as grounds for parenthood make people feel questioned as parents, negatively affecting parental welfare. Policy makers need to take into account the consequences of an unregulated situation regarding surrogacy, and focus more on the child-parent relationship when regulating surrogacy.

8.
Glob Health Action ; 10(1): 1328890, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28604252

RESUMO

BACKGROUND: Surrogacy is a reproductive practice that has been strongly marketed in India as a solution for childless couples. As a result, the number of surrogacy clinics is increasing. Meanwhile, a global discourse on surrogacy, originating from a Western perspective, has characterized surrogacy as being exploitative of women in low-income settings, where poverty drives them to become surrogate mothers. OBJECTIVE: This study explored perspectives on surrogacy from men and women in Assam, an Indian state known to be a low-income setting. Surrogacy arrangements in Assam are still uncommon. It can be expected that the dominant global discourses on surrogacy will be unfamiliar to the general population, and the objective was also to position the results within the divergent global discourses of surrogacy. METHODS: In order to explore local views on surrogacy, we conducted individual interviews and focus group discussions with people from various socioeconomic groups in Assam. RESULTS: Our findings reveal that people in Assam perceive surrogacy as a good option for a childless couple, as it would result in a child who is a 'blood' relation - something highly desirable for sociocultural reasons. However, the part played by the surrogate mother complicates local views on surrogacy. Most people consider payment to the surrogate mother contrary to societal norms. A surrogate mother is also often judged in a moral light, either as a 'bad mother' for selling her child, or as a 'noble woman' who has helped a childless couple and deserves payment for her services. CONCLUSIONS: In order to decrease the stigmatization of women, a regulatory policy is needed that will take into account the complex understandings of surrogacy and perceptions of surrogate mothers in Indian society. In policy, the possible effect of the dominant exploitation discourse needs to be modulated by local understandings of this reproduction method.


Assuntos
Pobreza/psicologia , Normas Sociais , Estigma Social , Mães Substitutas/psicologia , Mães Substitutas/estatística & dados numéricos , Adolescente , Adulto , Idoso , Feminino , Grupos Focais , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Pobreza/estatística & dados numéricos , Gravidez , Pesquisa Qualitativa , Adulto Jovem
9.
PLoS One ; 10(5): e0126518, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25955178

RESUMO

Transnational surrogacy, when people travel abroad for reproduction with the help of a surrogate mother, is a heavily debated phenomenon. One of the most salient discourses on surrogacy is the one affirming that Westerners, in their quest for having a child, exploit poor women in countries such as India. As surrogacy within the Swedish health care system is not permitted, Swedish commissioning parents have used transnational surrogacy, and the majority has turned to India. This interview study aimed to explore how commissioning parents negotiate the present discourses on surrogacy. Findings from the study suggest that the commissioning parents' views on using surrogacy are influenced by competing discourses on surrogacy represented by media and surrogacy agencies. The use of this reproductive method resulted, then, in some ambiguity. Although commissioning parents defy the exploitation discourse by referring to what they have learnt about the surrogate mother's life situation and by pointing at the significant benefits for her, they still had a request for regulation of surrogacy in Sweden, to better protect all parties involved. This study, then, gives a complex view on surrogacy, where the commissioning parents simultaneously argue against the exploitation discourse but at the same time are uncertain if the surrogate mothers are well protected in the surrogacy arrangements. Their responses to the situation endorse the need for regulation both in Sweden and India.


Assuntos
Inseminação Artificial Heteróloga/ética , Inseminação Artificial Heteróloga/legislação & jurisprudência , Mães Substitutas/legislação & jurisprudência , Adulto , Criança , Feminino , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Pais , Gravidez , Suécia
10.
J Biomed Mater Res B Appl Biomater ; 103(1): 12-20, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24711247

RESUMO

The aim was to compare the osseointegration of grit-blasted implants with and without a hydrogen fluoride treatment in rat tibia and femur, and to visualize bone formation using state-of-the-art 3D visualization techniques. Grit-blasted implants were inserted in femur and tibia of 10 Sprague-Dawley rats (4 implants/rat). Four weeks after insertion, bone implant samples were retrieved. Selected samples were imaged in 3D using Synchrotron Radiation-based µCT (SRµCT). The 3D data was quantified and visualized using two novel visualization techniques, thread fly-through and 2D unfolding. All samples were processed to cut and ground sections and 2D histomorphometrical comparisons of bone implant contact (BIC), bone area (BA), and mirror image area (MI) were performed. BA values were statistically significantly higher for test implants than controls (p < 0.05), but BIC and MI data did not differ significantly. Thus, the results partly indicate improved bone formation at blasted and hydrogen fluoride treated implants, compared to blasted implants. The 3D analysis was a valuable complement to 2D analysis, facilitating improved visualization. However, further studies are required to evaluate aspects of 3D quantitative techniques, with relation to light microscopy that traditionally is used for osseointegration studies.


Assuntos
Parafusos Ósseos/efeitos adversos , Materiais Revestidos Biocompatíveis/efeitos adversos , Fêmur/ultraestrutura , Imageamento Tridimensional , Tíbia/ultraestrutura , Titânio/efeitos adversos , Animais , Masculino , Ratos , Ratos Sprague-Dawley
11.
Oral Health Dent Manag ; 13(3): 735-44, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25284549

RESUMO

Apart from the Maillard reaction, other processes, such as esterification, take place in carious tissue. The aim of the present study was to analyse sound and carious dentine in terms of ester groups and their reaction with hydrazine derivate using Fourier Transform Infrared Spectroscopy (FTIR) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Carious and sound dentine from human premolars were excavated in three series (Experimental Parts I-III) and separated into inner and outer layers of carious dentine. The excavated tooth material was analysed with FTIR (Part I). Carious and sound dentine were also exposed to different chemical treatments and analysed with FTIR-Attenuated Total Reflectance (FTIR-ATR; Part II) and ToF-SIMS (Part III). The FTIR absorption spectra showed that the carious tissue contained ester groups, not detected in sound dentine. The results also indicated a higher occurrence of ester groups in the inner dental caries layer than in the outer ones. Potential binding to these ester groups by hydrazine derivative was observed after different chemical treatments with both FTIR-ATR and ToF-SIMS. The results of the present study revealed ester groups unique to the carious dentine which, after reaction with hydrazine derivative, form a covalent bond not found in sound dentine. The staining of carious unique groups would be clinically helpful in detection and prevention unnecessary removal of sound dentine.

12.
Int J Dent ; 2013: 139615, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23737786

RESUMO

Nanoparticle-covered electrodes have altered properties as compared to conventional electrodes with same chemical composition. The changes originate from the large surface area and enhanced conduction. To test the mineralization capacity of such materials, TiO2 nanoparticles were deposited on titanium and gold substrates. The electrochemical properties were investigated using cyclic voltammetry and impedance spectroscopy while the mineralization was tested by immersion in simulated body fluid. Two types of nucleation and growth behaviours were observed. For smooth nanoparticle surfaces, the initial nucleation is fast with the formation of few small nuclei of hydroxyapatite. With time, an amorphous 2D film develops with a Ca/P ratio close to 1.5. For the rougher surfaces, the nucleation is delayed but once it starts, thick layers are formed. Also the electronic properties of the oxides were shown to be important. Both density of states (DOS) in the bandgap of TiO2 and the active area were determined. The maximum in DOS was found to correlate with the donor density (N d ) and the active surface area. The results clearly show that a rough surface with high conductivity is beneficial for formation of thick apatite layers, while the nanoparticle covered electrodes show early nucleation but limited apatite formation.

13.
Pathog Dis ; 67(3): 192-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23620182

RESUMO

Biofilm formation by Staphylococcus epidermidis is a cause of infections related to peritoneal dialysis (PD). We have used a PD catheter flow-cell model in combination with confocal scanning laser microscopy and atomic force microscopy to study biofilm formation by S. epidermidis. Adherence to serum-coated catheters was four times greater than to uncoated ones, suggesting that S. epidermidis binds to serum proteins on the catheter surface. Pseudomonas aeruginosa biofilm supernatant interfered with the formation of a serum protein coat thereby reducing the capacity for biofilm formation in S. epidermidis. Supernatants from ΔpelA, ΔpslBCD and ΔrhlAB strains of P. aeruginosa showed no differences from the wild-type supernatant indicating that the effect on serum coat formation was not due to rhamnolipids or the PelA and PslBCD polysaccharides. Supernatant from P. aeruginosa also dispersed established S. epidermidis biofilms. Supernatants lacking PelA or PslBCD showed no differences from the wild type but that from a ΔrhlAB strain, showed reduced, but not abolished, capacity for dispersal. This suggests that rhamnolipids are involved but not wholly responsible for the effect. Thus, supernatants from P. aeruginosa contain promising substances for the prevention and treatment of biofilm infections, although further work is required to identity more active components.


Assuntos
Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Produtos Biológicos/farmacologia , Cateteres/microbiologia , Pseudomonas aeruginosa/metabolismo , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/fisiologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Produtos Biológicos/isolamento & purificação , Glicolipídeos/isolamento & purificação , Glicolipídeos/farmacologia , Humanos , Microscopia de Força Atômica , Microscopia Confocal , Staphylococcus epidermidis/isolamento & purificação
14.
J Biomed Mater Res B Appl Biomater ; 97(2): 364-72, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21442746

RESUMO

The aim of the present study was to compare the early interactions between leukocytes and three different surface modifications, suggested as bioactive. Blasted titanium discs were modified by alkali and heat treatment, sodium fluoride treatment, or hydroxyapatite coating. A number of these discs were also immersed in simulated body fluid (SBF) for a week, a treatment which yielded high levels of calcium and phosphate on each surface type. The specimens were exposed for human venous blood for 32 minutes and the respiratory burst response was measured in terms of reactive oxygen species with a luminometer, and coverage of viable cells with a fluorescence microscope after staining steps. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). A high respiratory burst response was found for HA coated titanium in comparison with the other surface groups (p < 0.0005). The SBF immersion resulted in an increased respiratory burst response (p < 0.0005) and removed statistically significant differences between the surface groups. Thus, the results in the present study indicate that different titanium surface modifications influence the early inflammatory response differently, and that calcium phosphate compounds increase the inflammatory response.


Assuntos
Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Leucócitos/imunologia , Titânio/química , Titânio/metabolismo , Líquidos Corporais/química , Durapatita/química , Temperatura Alta , Humanos , Teste de Materiais , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória/fisiologia , Fluoreto de Sódio/química , Propriedades de Superfície
15.
J Mater Sci Mater Med ; 20(9): 1869-79, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19415230

RESUMO

The aim of this study was to compare the nucleating and crystal growth behaviour of calcium phosphates on four types of potentially bioactive surfaces, using the simulated body fluid (SBF) model with added fibrinogen. Blasted titanium discs were modified by alkali and heat treatment, anodic oxidation, fluoride treatment, or hydroxyapatite coating. The discs were immersed in SBF with fibrinogen for periods of 3 days and 1, 2, 3 and 4 weeks. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry, scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), and x-ray photoelectron spectroscopy (XPS), respectively. All surface modifications showed early calcium phosphate formation after 3 days, and were almost completely covered by calcium phosphates after 2 weeks. After 4 weeks, the Ca/P ratio was approximately 2.0 for all surface groups except the fluoride modified surface, which had a Ca/P ratio of 1.0-1.5. XPS measurements of the nitrogen concentration, which can be interpreted as an indirect measure of the protein content, reached a peak value after 3 days immersion and decreased thereafter. In conclusion, the results in the present study, when compared to earlier SBF studies without proteins, showed that fibrinogen stimulates calcium phosphates formation. Furthermore, no pronounced differences could be detected between blasted controls and the potentially bioactive specimens.


Assuntos
Fosfatos de Cálcio/metabolismo , Fibrinogênio/química , Próteses e Implantes , Titânio/química , Durapatita/química , Eletrodos , Fluoretos/química , Temperatura Alta , Humanos , Interferometria/métodos , Microscopia Eletrônica de Varredura/métodos , Oxigênio/química , Propriedades de Superfície , Cicatrização , Raios X
16.
J Biomed Mater Res A ; 87(3): 624-31, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-18189300

RESUMO

Nanohydroxyapatite materials show similar chemistry to the bone apatite and depending on the underlying topography and the method of preparation, the nanohydroxyapatite may simulate the specific arrangement of the crystals in bone. Hydroxyapatite (HA) and other CaP materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area. In this study, very smooth electropolished titanium implants were used as substrata for nano-HA surface modification and as control. One of each implant (control and nano HA) was placed in the rabbit tibia in a surgical site 0.7 mm wider than the implant diameter, resulting in a gap of 0.35 mm on each implant side. Implant stability was ensured by a fixating plate fastened with two side screws. Topographical evaluation performed with an optical interferometer revealed the absence of microstructures on both implants and higher resolution evaluation with AFM showed similar nanoroughness parameters. Surface pores detected on the AFM measurements had similar diameter, depth, and surface porosity (%). Histological evaluation demonstrated similar bone formation for the nano HA and electropolished implants after 4 weeks of healing. These results do not support that nano-HA chemistry and nanotopography will enhance bone formation when placed in a gap-healing model. The very smooth surface may have prevented optimal activity of the material and future studies may evaluate the synergic effects of the surface chemistry, micro, and nanotopography, establishing the optimal parameters for each of them.


Assuntos
Remodelação Óssea , Materiais Revestidos Biocompatíveis/farmacologia , Durapatita/farmacologia , Implantes Experimentais , Titânio/farmacologia , Animais , Feminino , Interferometria , Teste de Materiais , Osseointegração , Coelhos , Propriedades de Superfície , Tíbia/cirurgia
17.
J Biomed Mater Res A ; 87(2): 299-307, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18181110

RESUMO

In a study model that aims to evaluate the effect of nanotopography on bone formation, micrometer structures known to alter bone formation, should be removed. Electropolished titanium implants were prepared to obtain a surface topography in the absence of micro structures, thereafter the implants were divided in two groups. The test group was modified with nanosize hydroxyapatite particles; the other group was left uncoated and served as control for the experiment. Topographical evaluation demonstrated increased nanoroughness parameters for the nano-HA implant and higher surface porosity compared to the control implant. The detected features had increased size and diameter equivalent to the nano-HA crystals present in the solution and the relative frequency of the feature size and diameter was very similar. Furthermore, feature density per microm(2) showed a decrease of 13.5% on the nano-HA implant. Chemical characterization revealed calcium and phosphorous ions on the modified implants, whereas the control implants consisted of pure titanium oxide. Histological evaluation demonstrated significantly increased bone formation to the coated (p < 0.05) compared to uncoated implants after 4 weeks of healing. These findings indicate for the first time that early bone formation is dependent on the nanosize hydroxyapatite features, but we are unaware if we see an isolated effect of the chemistry or of the nanotopography or a combination of both.


Assuntos
Hidroxiapatitas/química , Implantes Experimentais , Nanopartículas/química , Osteogênese/fisiologia , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Feminino , Hidroxiapatitas/metabolismo , Interferometria , Teste de Materiais , Microscopia de Força Atômica , Osseointegração , Porosidade , Coelhos , Propriedades de Superfície , Titânio/química
18.
J Mater Sci Mater Med ; 18(10): 1945-54, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17554602

RESUMO

The aim of the present study was to compare the nucleating and growing behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model. Titanium discs were blasted and then prepared by alkali and heat treatment, anodic oxidation, fluoridation, or hydroxyapatite coating. The discs were immersed in SBF for 1, 2, 4 and 6 weeks. Calcium phosphates were found on all specimens, as analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). After 1 and 2 weeks of SBF immersion more titanium was accessible with SEM/EDX on the blasted surfaces than the four bioactive surface types, indicating a difference in coverage by calcium phosphates. The Ca/P mean ratio of the surfaces was approximately 1.5 after 1 week, in contrast to the fluoridated specimens which displayed a Ca/P mean ratio of approximately 2. Powder X-ray diffraction (P-XRD) analyses showed the presence of hydroxyapatite on all types of surfaces after 4 and 6 weeks of immersion. The samples immersed for 6 weeks showed a higher degree of crystallinity than the samples immersed for 4 weeks. In conclusion, differences appeared at the early SBF immersion times of 1 and 2 weeks between controls and bioactive surface types, as well as between different bioactive surface types.


Assuntos
Líquidos Corporais/metabolismo , Fosfatos de Cálcio/metabolismo , Materiais Revestidos Biocompatíveis/metabolismo , Teste de Materiais , Próteses e Implantes , Materiais Revestidos Biocompatíveis/química , Microscopia Eletrônica de Varredura , Modelos Biológicos , Propriedades de Superfície , Titânio/química , Titânio/metabolismo , Difração de Raios X
19.
Clin Implant Dent Relat Res ; 9(2): 79-88, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17535331

RESUMO

BACKGROUND: The technique of free-form fabrication enables the production of controlled macroporous geometry inside ceramic scaffolds. Using scaffolds with identical macropore design makes it possible to study a relevant biological response linked to other specific changes of the material. PURPOSE: This study investigates the role of open micropores in hydroxyapatite (HA) scaffold during early bone healing to quantitatively ascertain whether microporosity in otherwise identical macroporous HA scaffolds can influence the bone response in rabbit tibia and femur at 6 weeks. MATERIALS AND METHODS: HA scaffolds (Ø: 3.8 mm) with and without microporosity were randomly installed in both cortical and trabecular bone sites of New Zealand White rabbits. The animals were sacrificed 6 weeks after surgery. Ground sections obtained from en bloc tissues containing scaffold and recipient bone were subjected to histological evaluation and histomorphometric analysis. RESULTS: Microscopy showed elevated amounts of bone ingrowth and bone contact inside the microporous HA (mHA) group as compared with non-mHA. CONCLUSION: The current study indicates that the presence of open scaffold microporosity in HA, as determined by the fabrication process, enhances the ability of ceramic scaffolds to promote bone ingrowth and bone contact.


Assuntos
Materiais Biocompatíveis/química , Substitutos Ósseos/química , Durapatita/química , Fêmur/fisiopatologia , Osteogênese/fisiologia , Tíbia/fisiopatologia , Animais , Feminino , Fêmur/patologia , Fêmur/cirurgia , Corantes Fluorescentes , Interferometria , Microscopia Eletrônica de Varredura , Osseointegração/fisiologia , Porosidade , Coelhos , Distribuição Aleatória , Propriedades de Superfície , Tíbia/patologia , Tíbia/cirurgia , Cicatrização/fisiologia
20.
Clin Oral Implants Res ; 18(3): 326-32, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17425657

RESUMO

Early bone response to cylindrical smooth titanium implants (S(a)=0.1 microm) inserted into the rabbit tibia was compared in a stable and nonstable regime. Surface roughness parameters were calculated from measurements obtained with optical interferometry and atomic force microscopy. Contrary to our hypothesis, the nonstable implant showed higher bone to metal contact and increased bone area in the endosteal region compared with the stable implant after 4 weeks of healing. Bone area measurements in the cortical region revealed similar values. Primitive woven bone was found in close contact with both implants, but significantly more with the nonstable implant. Finding more bone-to-implant contact (BIC) need not necessarily indicate that unstable implants were more strongly integrated. Primitive bone stage development observed indicates less strong implant anchorage than could be expected from BIC percentage alone. Stable implant design used in this study is a reliable model to evaluate submicron and nanostructures in vivo, as implant stability was achieved in the absence of microirregularaties.


Assuntos
Regeneração Óssea , Implantação Dentária Endóssea/métodos , Implantes Dentários , Animais , Materiais Biocompatíveis/química , Feminino , Nanotecnologia , Coelhos , Propriedades de Superfície , Tíbia/cirurgia , Titânio/química
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