Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains ... more Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains the alkaloids calystegines and swainsonine, which inhibit key cellular enzymes and cause systematic cell death. It is known that swainsonine is excreted in the amniotic fluid of dams exposed to the plant. Thus, the aim of this study was to verify whether the toxic effect of I. carnea on fetuses is due to exclusively the passage of the active principle of the plant through the placenta, or if the placentotoxic effect of swainsonine could collaborate in the adverse effects observed in the fetus. The teratogenic effects of exposure to the toxic principles of I. carnea were evaluated not only using the conventional protocol but also at later stages in the postnatal developmental period. Females were treated, from gestation day (GD) 6 until GD19, with 0.0, 1.0, 3.0 or 7.0 g/kg body weight of I. carnea dry leaves. The plant did not induce changes in reproductive performance or biochemical profile of the dams. Dams that received the highest dose of I. carnea showed cytoplasmic vacuolization in the liver, kidney and placental tissue. I. carnea promoted different lectin binding patterns in different areas of placental tissue. No fetal skeletal or visceral malformations was observed. The postnatal evaluation revealed a lower litter weight and a lower pup body weight one day after birth in the group that received the highest dose of I. carnea. Physical milestones were unaffected by the treatments. Female pups from all experimental groups exhibited a delay in achieving a negative geotaxis response. The results show that the toxic principle of I. carnea produces injury in utero in mothers and fetuses, but these deleterious effects were better demonstrated using postnatal evaluation.
The aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the... more The aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the peripheral nervous system, through a local injection of either 0,1% ethidium bromide solution or saline in the sciatic nerve of Cx 32 knockout mice. Euthanasia was performed ranging from 1, 2, 3, 7, 15, 21 to 30 days after injection. Histochemical, immunohistochemical, immunofluorescence and transmission electron microscopical techniques were used to analyze the development of the lesions. Within the sciatic nerves, Schwann cells initially showed signs of intoxication and rejected their sheaths; after seven days, some thin newly formed myelin sheaths with uneven compactness and redundant loops (tomacula) were conspicuous. We concluded that the regeneration of lost myelin sheaths within the PNS followed the pattern already reported for this model in other laboratory species. Therefore, these results suggest that absence of Cx 32 did not interfere with the normal pattern of remyelination ...
Journal of the Mechanical Behavior of Biomedical Materials, 2016
The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during stora... more The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during storage and its surface chemical state is usually changed by different sterilization methods. This causes an undesirable increase in surface hydrophobicity and results in osseointegration degradation. To overcome this problem, a low temperature hydrothermal (HT) sterilization method was proposed in this study. Briefly, 4 weeks-stored pure titanium SLA specimens were sterilized using a sealed glass bottle with pure water in an autoclave set at 121°C for 20min. Results showed that, stored SLA specimens were superhydrophobic before and after conventional autoclaving, whereas, HT sterilization decontaminated and endowed stored SLA surface with superhydrophilicity. Osteoblast spreading was greatly enhanced, ALP expression was upgraded and bone nodule formation was obviously promoted on HT sterilized specimens compared with autoclaved ones. More bone formation around HT sterilized specimens was observed and HT sterilization increased bonding strength of implant to bone by 95% and 127% after 2 and 4 weeks of healing, respectively. The simple, feasible HT sterilization restored osseointegration of SLA implant while diminishing recontamination as much as possible. Therefore, it is proposed as a standard sterilization method for implant practitioners and researches.
Journal of the mechanical behavior of biomedical materials, Jan 8, 2015
The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during stora... more The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during storage and its surface chemical state is usually changed by different sterilization methods. This causes an undesirable increase in surface hydrophobicity and results in osseointegration degradation. To overcome this problem, a low temperature hydrothermal (HT) sterilization method was proposed in this study. Briefly, 4 weeks-stored pure titanium SLA specimens were sterilized using a sealed glass bottle with pure water in an autoclave set at 121°C for 20min. Results showed that, stored SLA specimens were superhydrophobic before and after conventional autoclaving, whereas, HT sterilization decontaminated and endowed stored SLA surface with superhydrophilicity. Osteoblast spreading was greatly enhanced, ALP expression was upgraded and bone nodule formation was obviously promoted on HT sterilized specimens compared with autoclaved ones. More bone formation around HT sterilized specimens was obs...
INTRODUCTION: Hydroxyapatite (HAp) is widely used as biomaterial and a major component of bone. T... more INTRODUCTION: Hydroxyapatite (HAp) is widely used as biomaterial and a major component of bone. The effects and reparation of a nano-HAp implant in bone tissue is not fully understood in a living body. The study of in vivo bone implants using tissue molecular researching tools may help to understand how the bone reacts facing this kind of nano-HA implant. One important molecular pattern of bone is the membrane glycoprotein content, which leads to profile the differences of this content with the use of lectinhistochemistry (LHC). LHC is a technique which uses the lectins' ability of binding oligosaccharides combined to histochemistry tissue staining of membrane specific glycoproteins, thus the molecular approach [1]. METHODS: The nano-HAp powder were manufactured with addition of Mg 2+ 0.36%wt synthesized by neutralization method, the mean particle size ranged between 75nm to 100nm by TEM. To the in vivo assay were used 6 males Wistar rats, 3 formed the test group using nano-HAp ...
INTRODUCTION: Biomaterials based on titanium and its alloys are widely used in dentistry and orth... more INTRODUCTION: Biomaterials based on titanium and its alloys are widely used in dentistry and orthopaedics surgery due to their excellent mechanical properties and biological interaction. However, there are problems associated with the use of titanium as implant material. The high Young's modulus value when compared to the surrounding bone can cause problems of stress and subsequent dislocation of the implant 1 . To solve this problem have been developed osteoconductive porous materials for bone regeneration. One advantage in using materials with porous structure is the ability to allow a biological anchorage of surrounding tissues via bone ingrowth through the pores. Furthermore, the elastic modulus value can be adjusted between implant and trabecular bone values to match each other, thereby preventing bone resorption in the implant interface 2 . The Ti-13Nb-13Zr alloy studies has been developed due to its low elastic modulus combined with high values of mechanical strength and ...
To accurately evaluate in vivo hydroxyapatite (HA)-based im- plants, it is important that they be... more To accurately evaluate in vivo hydroxyapatite (HA)-based im- plants, it is important that they be an appropriate fit for the mod- el. This is necessary so we can recover the most from them during specimen analyses, and it is especially true when we take into ac- count the differences of laboratory animals’ sizes and metabolism. Two types of HA-based implants were evaluated, one consisting of a macroporous HA:β-TCP (MHA) processed by direct con- solidation using the protein-action technique, a globular protein based consolidation with ovalbumin, and one HA nanopowder with addition of Mg2+ 0.36%wt (NHA) synthesized by neutral- ization method, inside an ultrasound bath. The MHA sample shape to implant in the animal model was obtained by cutting the consolidated material with a 4-mm diameter core-drill. The NHA was used as powder. Wistar rats and New Zealand white rabbits were used for the in vivo tests. The implant surgery was performed under deep anesthesia with a pharmacologic associ...
The processing of porous ceramics spheres (PCS) has been developed for biphasic calcium phosphate... more The processing of porous ceramics spheres (PCS) has been developed for biphasic calcium phosphates (BCP), hydroxyapatite (HAp) and beta tricalcium phosphate (β-TCP) in order to be used mostly as bone fillers and drug delivery systems. The importance of the PCS is due to better accommodation of them in order to fill empty spaces and also because is more friendly to cells and bone tissue growth. Also is important to obtain a surface roughness to increase the surface area in contact with the living tissue and their fluids. There are several methods used to achieve the PCS form and most of them use suspensions based on liquids immiscibility effect or additives. The aim of this work was to achieve PCS of BCP, HAp and β-TCP with rough surface and varying size without using solutions or additives. The method developed is based on a mechanical continuous movement of the particles, relying on the normal ability of the ceramic powders to aggregate themselves while rolling in a cylindrical con...
Many techniques are used to assess biomaterials implants, always intending to measure osseointegr... more Many techniques are used to assess biomaterials implants, always intending to measure osseointegration success and tissue response facing the implanted material. Calcium phosphates are widely used as biomaterial and a major component of bone. Many processing methods have been used to achieve porous materials to allow bone ingrowth with an osteoconductive scaffold for bone. To obtain the macroporous BCP implant it was processed by direct consolidation using the protein-action technique, a globular protein based consolidation with ovalbumin. The samples were sintered at 1250°C for 30 minutes, after sintering samples were cut in 4mm diameter cylinders, with 73% volume of porosity and mean pore size ranging about 100 µm. In the present work the macroporous BCP of HAp:β-TCP is assessed after bone implantation in rabbits tibia by lectinhistochemistry (LHC) technique. Lectins are proteins from non-imune origin which binds with strong specificity carbohydrates, LHC is a technique which mark...
A Meningoencefalite Necrotizante (MEN) é uma encefalopatia causada por uma disfunção inflamatória... more A Meningoencefalite Necrotizante (MEN) é uma encefalopatia causada por uma disfunção inflamatória de característica necrotizante. O objetivo deste relato é descrever os aspectos clínicos e anatomopatológicos da Meningoencefalite Necrotizante (MEN) em um cão Maltês. A doença tem um caráter necrótico único e está relacionada intimamente à Encefalite do Cão Pug (ECP) devido a suas semelhanças, bem como à Leucoencefalite Necrotizante (LEN). Embora o primeiro relato de caso de ECP tenha mais de 15 anos e o primeiro relato de caso de MEN em Maltês tenha 11 anos, há muito a ser revelado sobre a etiologia e os mecanismos imunopatológicos da doença. Neste trabalho, relata-se o caso de um cão Maltês com sinais que foram compatíveis com a MEN. Foram detectadas nas imagens macroscópicas, cavitação cerebral, e na microscopia, perda de células do parênquima em certas regiões do córtex cerebral. A partir dessas descobertas descreve-se o primeiro caso de MEN em cão Maltês no Brasil.
Journal of Biomimetics, Biomaterials and Biomedical Engineering, 2014
Porous metallic structures have been developed to mimic the natural bone architecture, having int... more Porous metallic structures have been developed to mimic the natural bone architecture, having interconnected porosity, disposing enough room to cell migration, anchoring, vascularization, nourishing and proliferation of new bone tissue. Research involving porous titanium has been done with purpose to achieve desirable porosity and increasing of bone-implant bond strength interface. Samples of titanium were prepared by powder metallurgy (PM) with addition of different natural polymers (cornstarch, rice starch, potato starch and gelatin) at proportion of 16wt%. In aqueous solution the hydrogenated metallic powder (TiH2) and the polymer were mixed, homogenized and frozen in molds near net shape. The water was removed in kiln and the polymer by thermal treatment in air- (350°C/1h) before sintering in high-vacuum (1300°C/1h). The biological evaluation was performed by in vivo test in rabbits. Histological analysis was performed by scanning electron microscopy (SEM), energy dispersive spe...
ABSTRACT Titanium and its alloys are widely used as biomaterials and interact well with bone tiss... more ABSTRACT Titanium and its alloys are widely used as biomaterials and interact well with bone tissue. In order, to evaluate more than just morphological osseointegration by histological slides the work aimed to approach a molecular evaluation of bone-implant using lectinhistochemistry (LHC), which binds with high specificity carbohydrates (sugar residues) presents in membrane glycoproteins with the use of lectins. The implanted samples were obtained by powder metallurgy, Ti-13Nb-13Zr alloy with and without gelatin. Pores were achieved by adding gellatin 5 wt% to the hydrogenated metallic powder, after near net shape processing, the samples were thermal treated in vacuum (300 ºC/90min) and sintered in high-vacuum (1150 ºC/14h). The samples were characterized for porosity (~30%), and subsequently were implanted in rat's femur bone. After 4 weeks of healing process, bone with implant were sampled to perform LHC in paraffin embedded tissue in histological slides using the lectins PNA, UEA-1, WGA, sWGA and RCA-1. All samples osseointegrated well with the bone, no fibrous capsule was present in the bone which was in contact with the implant. With the molecular approach of osseointegration, adjustments in the processing and structure of macroporous titanium based implants can be performed to achieve friendly structure.
The porous metallic structure has been developed to mimic the natural bone architecture, having i... more The porous metallic structure has been developed to mimic the natural bone architecture, having interconnected porosity, disposing enough room to cell migration, anchoring, vascularization, nourishing and proliferation of new bone tissue. The titanium is used as porous implants due its excellent mechanical properties and biological interaction. Research evolving porous titanium has been done with purpose to achieve desirable pore size, total porosity percentage and influence of those in the increasing of bone-implant bond strength interface. Were prepared samples of titanium by powder metallurgy adding natural polymer: corn starch, rice starch, potato starch and gelatin; at proportion of 16 wt%. In aqueous solution the hydrogenated metallic powder (TiH2) and the polymer were mixed, homogenized and frozen in molds near net shape. The water was removed in kiln (38°C/12h) and the polymer by thermal treatment with air-oxidation (350 °C/1h) before sintering in high-vacuum (1300 °C/1h). R...
Studies of titanium and its alloys commonly used as biomaterials aim to improve bone-implant inte... more Studies of titanium and its alloys commonly used as biomaterials aim to improve bone-implant interface related problems, which may determine the quality, bone repairing time and therefore the implant clinical success. The goal of this study was to evaluate, in rats, osseointegration of macroporous implants produced by powder metallurgy (PM) method with controlled addition of gelatin. As control group, samples of commercially pure titanium (cpTi) and Ti-13Nb-13Zr alloy obtained by the PM process were used. To obtaining the porous samples, at most 15% in weight of gelatin was added to metallic powders, the samples were thermally treated in vacuum furnace, and sintered at 1150°C. The osseointegration evaluation was performed in Wistar rats, males, for a 28 days period. The morphological analyses, optical microscopy and scanning electron microscopy (SEM), evaluated qualitatively the osseointegration. The PM process modified by addition of gelatin provides with success the obtaining of p...
The potential of porous materials for applications in the medical, engineering and pharmaceutical... more The potential of porous materials for applications in the medical, engineering and pharmaceutical areas has been widely reported. Several processing techniques have contributed to the progress in research involving porous biomaterials. To this purpose, a globular protein based (i.e. ovalbumin) consolidation approach has been proposed. In the present study, a porous hydroxyapatite: -tricalcium phosphate - biphasic ceramics (BCP), was processed by direct consolidation using the protein-action technique. The processed porous ceramic exhibited appropriate pore configuration in terms of size, morphology and distribution. BCP cylindrical samples were implanted in male rabbits tibia to the evaluation of the initial biocompatibility and osseointegration for a 30 days period. The morphological analyses, optical microscopy and scanning electron microscopy evaluated the osseointegration. A rough surface pattern displayed by the ceramics seemed to have improved cell adhesion and proliferation ...
Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains ... more Ipomoea carnea is a toxic plant found in Brazil and other tropical countries. The plant contains the alkaloids calystegines and swainsonine, which inhibit key cellular enzymes and cause systematic cell death. It is known that swainsonine is excreted in the amniotic fluid of dams exposed to the plant. Thus, the aim of this study was to verify whether the toxic effect of I. carnea on fetuses is due to exclusively the passage of the active principle of the plant through the placenta, or if the placentotoxic effect of swainsonine could collaborate in the adverse effects observed in the fetus. The teratogenic effects of exposure to the toxic principles of I. carnea were evaluated not only using the conventional protocol but also at later stages in the postnatal developmental period. Females were treated, from gestation day (GD) 6 until GD19, with 0.0, 1.0, 3.0 or 7.0 g/kg body weight of I. carnea dry leaves. The plant did not induce changes in reproductive performance or biochemical profile of the dams. Dams that received the highest dose of I. carnea showed cytoplasmic vacuolization in the liver, kidney and placental tissue. I. carnea promoted different lectin binding patterns in different areas of placental tissue. No fetal skeletal or visceral malformations was observed. The postnatal evaluation revealed a lower litter weight and a lower pup body weight one day after birth in the group that received the highest dose of I. carnea. Physical milestones were unaffected by the treatments. Female pups from all experimental groups exhibited a delay in achieving a negative geotaxis response. The results show that the toxic principle of I. carnea produces injury in utero in mothers and fetuses, but these deleterious effects were better demonstrated using postnatal evaluation.
The aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the... more The aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the peripheral nervous system, through a local injection of either 0,1% ethidium bromide solution or saline in the sciatic nerve of Cx 32 knockout mice. Euthanasia was performed ranging from 1, 2, 3, 7, 15, 21 to 30 days after injection. Histochemical, immunohistochemical, immunofluorescence and transmission electron microscopical techniques were used to analyze the development of the lesions. Within the sciatic nerves, Schwann cells initially showed signs of intoxication and rejected their sheaths; after seven days, some thin newly formed myelin sheaths with uneven compactness and redundant loops (tomacula) were conspicuous. We concluded that the regeneration of lost myelin sheaths within the PNS followed the pattern already reported for this model in other laboratory species. Therefore, these results suggest that absence of Cx 32 did not interfere with the normal pattern of remyelination ...
Journal of the Mechanical Behavior of Biomedical Materials, 2016
The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during stora... more The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during storage and its surface chemical state is usually changed by different sterilization methods. This causes an undesirable increase in surface hydrophobicity and results in osseointegration degradation. To overcome this problem, a low temperature hydrothermal (HT) sterilization method was proposed in this study. Briefly, 4 weeks-stored pure titanium SLA specimens were sterilized using a sealed glass bottle with pure water in an autoclave set at 121°C for 20min. Results showed that, stored SLA specimens were superhydrophobic before and after conventional autoclaving, whereas, HT sterilization decontaminated and endowed stored SLA surface with superhydrophilicity. Osteoblast spreading was greatly enhanced, ALP expression was upgraded and bone nodule formation was obviously promoted on HT sterilized specimens compared with autoclaved ones. More bone formation around HT sterilized specimens was observed and HT sterilization increased bonding strength of implant to bone by 95% and 127% after 2 and 4 weeks of healing, respectively. The simple, feasible HT sterilization restored osseointegration of SLA implant while diminishing recontamination as much as possible. Therefore, it is proposed as a standard sterilization method for implant practitioners and researches.
Journal of the mechanical behavior of biomedical materials, Jan 8, 2015
The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during stora... more The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during storage and its surface chemical state is usually changed by different sterilization methods. This causes an undesirable increase in surface hydrophobicity and results in osseointegration degradation. To overcome this problem, a low temperature hydrothermal (HT) sterilization method was proposed in this study. Briefly, 4 weeks-stored pure titanium SLA specimens were sterilized using a sealed glass bottle with pure water in an autoclave set at 121°C for 20min. Results showed that, stored SLA specimens were superhydrophobic before and after conventional autoclaving, whereas, HT sterilization decontaminated and endowed stored SLA surface with superhydrophilicity. Osteoblast spreading was greatly enhanced, ALP expression was upgraded and bone nodule formation was obviously promoted on HT sterilized specimens compared with autoclaved ones. More bone formation around HT sterilized specimens was obs...
INTRODUCTION: Hydroxyapatite (HAp) is widely used as biomaterial and a major component of bone. T... more INTRODUCTION: Hydroxyapatite (HAp) is widely used as biomaterial and a major component of bone. The effects and reparation of a nano-HAp implant in bone tissue is not fully understood in a living body. The study of in vivo bone implants using tissue molecular researching tools may help to understand how the bone reacts facing this kind of nano-HA implant. One important molecular pattern of bone is the membrane glycoprotein content, which leads to profile the differences of this content with the use of lectinhistochemistry (LHC). LHC is a technique which uses the lectins' ability of binding oligosaccharides combined to histochemistry tissue staining of membrane specific glycoproteins, thus the molecular approach [1]. METHODS: The nano-HAp powder were manufactured with addition of Mg 2+ 0.36%wt synthesized by neutralization method, the mean particle size ranged between 75nm to 100nm by TEM. To the in vivo assay were used 6 males Wistar rats, 3 formed the test group using nano-HAp ...
INTRODUCTION: Biomaterials based on titanium and its alloys are widely used in dentistry and orth... more INTRODUCTION: Biomaterials based on titanium and its alloys are widely used in dentistry and orthopaedics surgery due to their excellent mechanical properties and biological interaction. However, there are problems associated with the use of titanium as implant material. The high Young's modulus value when compared to the surrounding bone can cause problems of stress and subsequent dislocation of the implant 1 . To solve this problem have been developed osteoconductive porous materials for bone regeneration. One advantage in using materials with porous structure is the ability to allow a biological anchorage of surrounding tissues via bone ingrowth through the pores. Furthermore, the elastic modulus value can be adjusted between implant and trabecular bone values to match each other, thereby preventing bone resorption in the implant interface 2 . The Ti-13Nb-13Zr alloy studies has been developed due to its low elastic modulus combined with high values of mechanical strength and ...
To accurately evaluate in vivo hydroxyapatite (HA)-based im- plants, it is important that they be... more To accurately evaluate in vivo hydroxyapatite (HA)-based im- plants, it is important that they be an appropriate fit for the mod- el. This is necessary so we can recover the most from them during specimen analyses, and it is especially true when we take into ac- count the differences of laboratory animals’ sizes and metabolism. Two types of HA-based implants were evaluated, one consisting of a macroporous HA:β-TCP (MHA) processed by direct con- solidation using the protein-action technique, a globular protein based consolidation with ovalbumin, and one HA nanopowder with addition of Mg2+ 0.36%wt (NHA) synthesized by neutral- ization method, inside an ultrasound bath. The MHA sample shape to implant in the animal model was obtained by cutting the consolidated material with a 4-mm diameter core-drill. The NHA was used as powder. Wistar rats and New Zealand white rabbits were used for the in vivo tests. The implant surgery was performed under deep anesthesia with a pharmacologic associ...
The processing of porous ceramics spheres (PCS) has been developed for biphasic calcium phosphate... more The processing of porous ceramics spheres (PCS) has been developed for biphasic calcium phosphates (BCP), hydroxyapatite (HAp) and beta tricalcium phosphate (β-TCP) in order to be used mostly as bone fillers and drug delivery systems. The importance of the PCS is due to better accommodation of them in order to fill empty spaces and also because is more friendly to cells and bone tissue growth. Also is important to obtain a surface roughness to increase the surface area in contact with the living tissue and their fluids. There are several methods used to achieve the PCS form and most of them use suspensions based on liquids immiscibility effect or additives. The aim of this work was to achieve PCS of BCP, HAp and β-TCP with rough surface and varying size without using solutions or additives. The method developed is based on a mechanical continuous movement of the particles, relying on the normal ability of the ceramic powders to aggregate themselves while rolling in a cylindrical con...
Many techniques are used to assess biomaterials implants, always intending to measure osseointegr... more Many techniques are used to assess biomaterials implants, always intending to measure osseointegration success and tissue response facing the implanted material. Calcium phosphates are widely used as biomaterial and a major component of bone. Many processing methods have been used to achieve porous materials to allow bone ingrowth with an osteoconductive scaffold for bone. To obtain the macroporous BCP implant it was processed by direct consolidation using the protein-action technique, a globular protein based consolidation with ovalbumin. The samples were sintered at 1250°C for 30 minutes, after sintering samples were cut in 4mm diameter cylinders, with 73% volume of porosity and mean pore size ranging about 100 µm. In the present work the macroporous BCP of HAp:β-TCP is assessed after bone implantation in rabbits tibia by lectinhistochemistry (LHC) technique. Lectins are proteins from non-imune origin which binds with strong specificity carbohydrates, LHC is a technique which mark...
A Meningoencefalite Necrotizante (MEN) é uma encefalopatia causada por uma disfunção inflamatória... more A Meningoencefalite Necrotizante (MEN) é uma encefalopatia causada por uma disfunção inflamatória de característica necrotizante. O objetivo deste relato é descrever os aspectos clínicos e anatomopatológicos da Meningoencefalite Necrotizante (MEN) em um cão Maltês. A doença tem um caráter necrótico único e está relacionada intimamente à Encefalite do Cão Pug (ECP) devido a suas semelhanças, bem como à Leucoencefalite Necrotizante (LEN). Embora o primeiro relato de caso de ECP tenha mais de 15 anos e o primeiro relato de caso de MEN em Maltês tenha 11 anos, há muito a ser revelado sobre a etiologia e os mecanismos imunopatológicos da doença. Neste trabalho, relata-se o caso de um cão Maltês com sinais que foram compatíveis com a MEN. Foram detectadas nas imagens macroscópicas, cavitação cerebral, e na microscopia, perda de células do parênquima em certas regiões do córtex cerebral. A partir dessas descobertas descreve-se o primeiro caso de MEN em cão Maltês no Brasil.
Journal of Biomimetics, Biomaterials and Biomedical Engineering, 2014
Porous metallic structures have been developed to mimic the natural bone architecture, having int... more Porous metallic structures have been developed to mimic the natural bone architecture, having interconnected porosity, disposing enough room to cell migration, anchoring, vascularization, nourishing and proliferation of new bone tissue. Research involving porous titanium has been done with purpose to achieve desirable porosity and increasing of bone-implant bond strength interface. Samples of titanium were prepared by powder metallurgy (PM) with addition of different natural polymers (cornstarch, rice starch, potato starch and gelatin) at proportion of 16wt%. In aqueous solution the hydrogenated metallic powder (TiH2) and the polymer were mixed, homogenized and frozen in molds near net shape. The water was removed in kiln and the polymer by thermal treatment in air- (350°C/1h) before sintering in high-vacuum (1300°C/1h). The biological evaluation was performed by in vivo test in rabbits. Histological analysis was performed by scanning electron microscopy (SEM), energy dispersive spe...
ABSTRACT Titanium and its alloys are widely used as biomaterials and interact well with bone tiss... more ABSTRACT Titanium and its alloys are widely used as biomaterials and interact well with bone tissue. In order, to evaluate more than just morphological osseointegration by histological slides the work aimed to approach a molecular evaluation of bone-implant using lectinhistochemistry (LHC), which binds with high specificity carbohydrates (sugar residues) presents in membrane glycoproteins with the use of lectins. The implanted samples were obtained by powder metallurgy, Ti-13Nb-13Zr alloy with and without gelatin. Pores were achieved by adding gellatin 5 wt% to the hydrogenated metallic powder, after near net shape processing, the samples were thermal treated in vacuum (300 ºC/90min) and sintered in high-vacuum (1150 ºC/14h). The samples were characterized for porosity (~30%), and subsequently were implanted in rat's femur bone. After 4 weeks of healing process, bone with implant were sampled to perform LHC in paraffin embedded tissue in histological slides using the lectins PNA, UEA-1, WGA, sWGA and RCA-1. All samples osseointegrated well with the bone, no fibrous capsule was present in the bone which was in contact with the implant. With the molecular approach of osseointegration, adjustments in the processing and structure of macroporous titanium based implants can be performed to achieve friendly structure.
The porous metallic structure has been developed to mimic the natural bone architecture, having i... more The porous metallic structure has been developed to mimic the natural bone architecture, having interconnected porosity, disposing enough room to cell migration, anchoring, vascularization, nourishing and proliferation of new bone tissue. The titanium is used as porous implants due its excellent mechanical properties and biological interaction. Research evolving porous titanium has been done with purpose to achieve desirable pore size, total porosity percentage and influence of those in the increasing of bone-implant bond strength interface. Were prepared samples of titanium by powder metallurgy adding natural polymer: corn starch, rice starch, potato starch and gelatin; at proportion of 16 wt%. In aqueous solution the hydrogenated metallic powder (TiH2) and the polymer were mixed, homogenized and frozen in molds near net shape. The water was removed in kiln (38°C/12h) and the polymer by thermal treatment with air-oxidation (350 °C/1h) before sintering in high-vacuum (1300 °C/1h). R...
Studies of titanium and its alloys commonly used as biomaterials aim to improve bone-implant inte... more Studies of titanium and its alloys commonly used as biomaterials aim to improve bone-implant interface related problems, which may determine the quality, bone repairing time and therefore the implant clinical success. The goal of this study was to evaluate, in rats, osseointegration of macroporous implants produced by powder metallurgy (PM) method with controlled addition of gelatin. As control group, samples of commercially pure titanium (cpTi) and Ti-13Nb-13Zr alloy obtained by the PM process were used. To obtaining the porous samples, at most 15% in weight of gelatin was added to metallic powders, the samples were thermally treated in vacuum furnace, and sintered at 1150°C. The osseointegration evaluation was performed in Wistar rats, males, for a 28 days period. The morphological analyses, optical microscopy and scanning electron microscopy (SEM), evaluated qualitatively the osseointegration. The PM process modified by addition of gelatin provides with success the obtaining of p...
The potential of porous materials for applications in the medical, engineering and pharmaceutical... more The potential of porous materials for applications in the medical, engineering and pharmaceutical areas has been widely reported. Several processing techniques have contributed to the progress in research involving porous biomaterials. To this purpose, a globular protein based (i.e. ovalbumin) consolidation approach has been proposed. In the present study, a porous hydroxyapatite: -tricalcium phosphate - biphasic ceramics (BCP), was processed by direct consolidation using the protein-action technique. The processed porous ceramic exhibited appropriate pore configuration in terms of size, morphology and distribution. BCP cylindrical samples were implanted in male rabbits tibia to the evaluation of the initial biocompatibility and osseointegration for a 30 days period. The morphological analyses, optical microscopy and scanning electron microscopy evaluated the osseointegration. A rough surface pattern displayed by the ceramics seemed to have improved cell adhesion and proliferation ...
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