Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 55
Filtrar
1.
Ticks Tick Borne Dis ; 14(3): 102147, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36893500

RESUMO

Rhipicephalus microplus tick is the main ectoparasite of cattle in Brazil. The exhaustive use of chemical acaricides to control this tick has favored the selection of resistant tick populations. Entomopathogenic fungi, as Metarhizium anisopliae, has been described as a potential biocontroller of ticks. Therefore, the aim of this study was to evaluate the in vivo efficacy of two oil based formulations of M. anisopliae for the control of the cattle tick R. microplus under field conditions using a cattle spray race as a method of treatment. Initially, in vitro assays were carried out with an aqueous suspension of M. anisopliae, using mineral oil and/or silicon oil. A potential synergism between oils and fungus conidia for tick control was demonstrated. Additionally, the usefulness of silicon oil in order to reduce mineral oil concentration, while improving formulation efficacy was illustrated. Based on the in vitro results, two formulations were selected for use in the field trial: MaO1 (107 conidia/mL plus 5% mineral oil) and MaO2 (107 conidia/mL plus 2.5% mineral oil and 0.01% silicon oil). The adjuvants concentrations (mineral and silicon oils) were chosen since preliminary data indicate that higher concentrations caused significant mortality in adult ticks. For this, 30 naturally infested heifers were divided into three groups based on previous tick counts. The control group did not receive treatment. The selected formulations were applied on animals using a cattle spray race. Subsequently, tick load was evaluated weekly by counting. The MaO1 treatment significantly reduced the tick count only on day +21, reaching approximately 55% efficacy. On the other hand, MaO2 showed significantly lower tick counts on days +7, +14, and +21 after treatment, with weekly efficacy achieving 66%. The results showed a substantial reduction of tick infestation, up to day +28, using a novel formulation of M. anisopliae based in the mixture of two oils. Moreover, we have shown, for the first time, the feasibility of employing formulations of M. anisopliae for large-scale treatment methods, such as a cattle spray race, which in turn, may increase the use and adhesion to biological control tools among farmers.


Assuntos
Doenças dos Bovinos , Metarhizium , Rhipicephalus , Infestações por Carrapato , Animais , Bovinos , Feminino , Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/parasitologia , Óleo Mineral , Óleos , Controle Biológico de Vetores/métodos , Rhipicephalus/microbiologia , Esporos Fúngicos , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterinária , Infestações por Carrapato/parasitologia
2.
Vet Parasitol Reg Stud Reports ; 24: 100546, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-34024364

RESUMO

South American opossums of the order Didelphimorphia are considered sentinels for zoonotic infections and environmental diseases, such as for Chagas disease caused by Trypanosoma cruzi. Nevertheless, there is a paucity of data regarding protozoan diseases such Toxoplasma gondii and Neospora caninum in Neotropical marsupials; despite these pathogens have been considered threats to some marsupial species. The aim of this study was to determine whether Didelphis albiventris and Philander frenatus opossums from southern Brazil had been previously exposed to T. cruzi, T. gondii or N. caninum. Opossum samples were obtained by live-trapping of free-ranging animals and collection at wildlife rehabilitation centers in Rio Grande do Sul (RS) state, Brazil. The detection of anti-T. cruzi and anti-T. gondii antibodies was performed by indirect hemagglutination and anti-N. caninum antibodies by competitive enzyme-linked immunosorbent assay. In total, samples were collected from 76 marsupials from nine municipalities in RS state, including 69 D. albiventris (white-eared opossum), and seven were P. frenatus (southern four-eyed opossum). For T. cruzi, 11% were seropositive, and for T. gondii 26% were seropositive. None of the marsupials sampled here were seropositive for N. caninum. Risk factor analysis showed that free-living animals were about five-fold more likely to be infected by T. gondii than were rescued animals. Our study showed the exposure of Neotropical marsupials (D. albiventris and P. frenatus) to protozoan pathogens T. cruzi and T. gondii, while no evidence of N. caninum exposure was found. The set of results presented here may have an effect on ecology and conservation of the studied species and may also indicate possible sentinels of these pathogen circulation.


Assuntos
Coccidiose , Didelphis , Neospora , Toxoplasma , Toxoplasmose Animal , Trypanosoma cruzi , Animais , Anticorpos Antiprotozoários , Brasil/epidemiologia , Coccidiose/epidemiologia , Coccidiose/veterinária , Estudos Soroepidemiológicos , Toxoplasmose Animal/epidemiologia
3.
Med Vet Entomol ; 33(4): 536-540, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30848844

RESUMO

Fleas are insects with a worldwide distribution that have been implicated in the transmission of several pathogens. The present study aimed to investigate the presence of Rickettsia spp. (Rickettsiales: Rickettsiaceae) and Bartonella spp. (Rhizobiales: Bartonellaceae) in fleas from free-ranging crab-eating foxes Cerdocyon thous (Linnaeus, 1766) (Carnivora: Canidae) from Rio Grande do Sul, southern Brazil. Fleas were collected manually from animals and used for the molecular detection of Rickettsia spp. and Bartonella spp. Twenty-nine C. thous were sampled in six municipalities. Four foxes were parasitized by 10 fleas, all of which were identified as Ctenocephalides felis (Bouché, 1935) (Siphonaptera: Pulicidae). DNA from Rickettsia felis Bouyer et al., 2001 and Rickettsia asembonensis Maina et al., 2016 were found in three and eight fleas, respectively. In four fleas, DNA of Bartonella sp. was identified. Phylogenetic analysis grouped Bartonella sp. together with other genotypes previously reported in C. felis worldwide. The scenario described in the present study highlights a Neotropical canid parasitized by the invasive cosmopolitan cat flea, which in turn, is carrying potentially invasive vector-borne microorganisms. These findings suggest that C. felis is adapted to wild hosts in wilderness areas in southern Brazil, hypothetically exposing the Neotropical fauna to unknown ecological and health disturbances.


Assuntos
Bartonella/isolamento & purificação , Canidae/parasitologia , Ctenocephalides/microbiologia , Infestações por Pulgas/veterinária , Rickettsia/isolamento & purificação , Animais , Brasil/epidemiologia , Infestações por Pulgas/epidemiologia , Infestações por Pulgas/parasitologia , Insetos Vetores/microbiologia , Prevalência
4.
Transbound Emerg Dis ; 65(2): e224-e230, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29119703

RESUMO

Spotted fevers are tick-borne diseases associated with various Rickettsia species. Rickettsia parkeri sensu stricto (s.s.) is the agent of an emerging eschar-associated rickettsiosis in humans from the USA and South American Pampa. Considering that R. parkeri s.s. is restricted to Americas and the potential role of dogs in the epidemiology of the disease, it is thus reasonable to hypothesize that wild canids could be involved in the enzootic cycle of this rickettsiosis. The aim of this work was to investigate the potential role of the wild canids from Pampa, Cerdocyon thous (crab-eating fox) and Lycalopex gymnocercus (Pampas fox), in the ecology of R. parkeri s.s. For that, 32 live-trapped free-ranging wild canids were sampled. Ticks were observed in 30 of the 32 foxes. Of the 292 ticks collected, 22 (7.5%) were positive by PCR for the presence of R. parkeri s.s. DNA. Also, 20 (62%) wild canids showed antibodies against R. parkeri. The results suggest that wild canids are involved in the enzootic cycle of R. parkeri s.s. in the Pampa biome and could be responsible for pathogen (and its vectors) dispersal.


Assuntos
Vetores Aracnídeos/microbiologia , Raposas/microbiologia , Infecções por Rickettsia/microbiologia , Rickettsia/isolamento & purificação , Doenças Transmitidas por Carrapatos/microbiologia , Carrapatos/microbiologia , Animais , Animais Selvagens , Brasil/epidemiologia , Reservatórios de Doenças/microbiologia , Ecossistema , Feminino , Raposas/imunologia , Humanos , Masculino , Reação em Cadeia da Polimerase , Rickettsia/genética , Rickettsia/imunologia , Infecções por Rickettsia/epidemiologia , Infecções por Rickettsia/transmissão , Doenças Transmitidas por Carrapatos/epidemiologia , Doenças Transmitidas por Carrapatos/transmissão , Zoonoses
5.
Ticks Tick Borne Dis ; 7(5): p. 730-733, 2016.
Artigo | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: but-ib14611

RESUMO

Ornithodoros brasiliensis: Aragao is an endemic tick restricted to the highlands of the state of Rio Grande do Sul, Brazil. This species is very aggressive toward humans, causing fever, great pain and intense inflammatory response at the bite site. It is also very aggressive toward dogs, and tick toxicosis syndrome has been reported in this host. In order to elucidate the biology of this tick, the present study describes its life cycle under laboratory conditions, using guinea pigs as hosts for two generations. In the nonparasitic phase, the ticks were maintained in sand, in an incubator under controlled conditions. The larvae molted to the nymphal stage without feeding, and five nymphal stages (N1, N2, N3, N4 and N5) were observed in both generations. In both generations emergence of adults started from N3 when sex ratio was 0.85:1 (23 males and 27 females) in F1 and 0.63:1 (34 males and 54 females) in F2. For both generations, N4 generated more females, while N5 only produced females. The pre-ecdysis period of the nymphs ranged from 31.1 to 38.6 days. Two gonotrophic cycles were observed, and the first one presented a higher average number of eggs deposited (N=139) than the second (N=73.8). The mean duration of the life cycle (egg to egg) of O. brasiliensis was 215.4 days for the first generation and 195 days for the second


Assuntos
Parasitologia
6.
Vet Parasitol ; 214(3-4): 322-6, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26255094

RESUMO

Anaplasma marginale is an obligate intracellular pathogen that infects the erythrocytes of calves, causing bovine anaplasmosis. This rickettsia is biologically transmitted by several species of ticks. In tropical and subtropical regions of the world, Rhipicephalus microplus is the main vector. Due to their mobility and longevity, the adult males play an important role in the transmission of A. marginale to calves. Some studies have demonstrated that A. marginale can be intrastadially and interstadially transmitted in R. microplus, but the transovarial transmission has not been demonstrated so far. In the present study, we investigated the effects of low temperature on both the A. marginale migration from infected females to their offspring and reproductive parameters of the tick R. microplus. The larvae of R. microplus fed on a calf infected with the strain Jaboticabal of A. marginale. At the end of the parasitic phase, fully engorged females were incubated at either 18°C or 28°C for oviposition. Although A. marginale was detected in the salivary glands of the females, demonstrating that the ticks were successfully infected, the presence of rickettsia was not detected in the offspring. However, the preoviposition period of the non-infected females maintained at 18°C was longer than that of those maintained at 28°C. In addition, the average weight of the mass of eggs as well as the egg production efficiency (ratio of the egg mass weight to the female weight) of the females maintained at 18°C were significantly lower than those of the females incubated at 28°C. There was no larval hatching from the eggs maintained exclusively at 18°C, even at 65 days after female detachment. Hatching occurred only when the eggs maintained at 18°C were transferred to 28°C at 20 days after female detachment (18°C/28°C). We also verified a significantly higher larvae conversion efficiency (ratio of the larvae mass weight to the egg mass weight) in the group of females maintained exclusively at 28°C compared to those from the 18°C/28°C group. Collectively, our results reinforce that low temperature exerts negative effects on female fertility and egg development in R. microplus, although it has no influence on A. marginale transmission to the progeny. In the field, the detrimental effects of temperatures on tick reproductive fitness lead to a reduction of tick population, which may cause a decrease in the incidence of bovine anaplasmosis.


Assuntos
Anaplasma marginale/fisiologia , Anaplasmose/transmissão , Doenças dos Bovinos/transmissão , Temperatura Baixa , Rhipicephalus/microbiologia , Anaplasmose/microbiologia , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Feminino , Larva , Masculino , Oviposição/fisiologia , Reprodução/fisiologia , Glândulas Salivares/microbiologia , Zigoto/microbiologia
7.
Parasitology ; 136(11): 1339-49, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19627637

RESUMO

Ticks are blood-feeding arthropods widely distributed in the world and vectors of several diseases. As haematophagy demands evasion strategies and repeatedly infested hosts develop protective immune responses, we investigated the mechanisms of the Rhipicephalus (Boophilus) microplus saliva anti-haemostatic activity and the possible relationship between the acquired natural anti-tick host resistance and anti-haemostatic action. For this purpose, we studied the effects of R. microplus saliva on different pathways of haemostasis and tested whether repeated infested bovine sera (RIBS) are able to abolish salivary anti-haemostatic activities. R. microplus saliva (i) displays inhibitory activity upon collagen-induced platelet aggregation; (ii) inhibits the induction of endothelial pro-coagulant state; and (iii) reduces thrombogenesis in vivo. RIBS were shown to be able to partially block the delay of coagulation and the anti-thrombotic effect of saliva, and to totally abolish the modulation of endothelium activation. Conversely, RIBS has no effect on the inhibition of platelet aggregation. These results show, for the first time, the neutralization ability of sera from acquired resistance hosts against tick anti-haemostatics. Moreover, this is the first report of a haematophagous parasite able to modulate endothelial cell pro-coagulant state, and addresses the presence of anti-platelet and anti-thrombotic activity in R. microplus saliva.


Assuntos
Doenças dos Bovinos/parasitologia , Hemostasia/efeitos dos fármacos , Soros Imunes , Rhipicephalus/metabolismo , Saliva/fisiologia , Infestações por Carrapato/parasitologia , Animais , Coagulação Sanguínea/efeitos dos fármacos , Bovinos , Doenças dos Bovinos/imunologia , Linhagem Celular , Modelos Animais de Doenças , Células Endoteliais , Hemostasia/fisiologia , Interações Hospedeiro-Parasita , Humanos , Soros Imunes/efeitos dos fármacos , Soros Imunes/imunologia , Soros Imunes/farmacologia , Masculino , Testes de Neutralização , Agregação Plaquetária/efeitos dos fármacos , Coelhos , Ratos , Ratos Wistar , Rhipicephalus/fisiologia , Saliva/imunologia , Infestações por Carrapato/imunologia , Trombose Venosa
8.
Res Vet Sci ; 86(1): 56-62, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18571684

RESUMO

The tick Rhipicephalus (Boophilus) microplus is a hematophagous ectoparasite that causes considerable economic losses to cattle breeding. Although R. microplus saliva contains several molecules that interfere with the blood coagulation process, so far the systemic alterations in the host hemostatic system have not been described. This study aims to determine if R. microplus infestation induces any disturbance to the host's hemostatic system. To address these questions, six calves were experimentally infested with 20,000 R. microplus larvae and their blood was collected before and 7, 14 and 21 days post-infestation. Collagen and ADP-induced platelet aggregation as well as coagulation (activated partial thromboplastin time and prothrombin time) decreased in infested bovines. Platelet blood count and fibrinogen increased during the course of infestation, probably as a compensatory response. These alterations may play a role in host health status, and show that the host cannot fully counteract the tick anti-hemostatic mechanisms.


Assuntos
Doenças dos Bovinos/sangue , Doenças dos Bovinos/parasitologia , Hemostasia/fisiologia , Rhipicephalus/crescimento & desenvolvimento , Infestações por Carrapato/sangue , Infestações por Carrapato/veterinária , Animais , Bovinos , Feminino , Fibrinogênio/análise , Tempo de Tromboplastina Parcial/veterinária , Agregação Plaquetária/fisiologia , Contagem de Plaquetas/veterinária , Tempo de Protrombina/veterinária , Infestações por Carrapato/parasitologia
9.
Photomed Laser Surg ; 23(1): 10-4, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15782025

RESUMO

OBJECTIVE: The purpose of this study was to define the optimal irradiation conditions of a KTP laser during root planing treatment. METHODS: The surfaces of 60 single-root human teeth were scaled with conventional instruments before lasing. The pulpal temperature increase was measured by means of one thermocouple placed in the pulp chamber and a second one placed on the root surface at 1 mm from the irradiation site. The influence of variables of coloration by Acid Red 52 (photosensitizer), scanning speed, dentin thickness, and probe position was analyzed for a constant exposure time of 15 sec and 500 mw (spot size diameter, 0.5 mm). The pulpal temperature was below 3 degrees C for the adjustments. RESULTS: The irradiation on one point of root surface had the following results: The application of photosensitizer on the root surface before lasing produced a 50% higher temperature rise within the pulp than in the case without the application of the photosensitizer. The temperature rise in the pulp chamber was below 3 degrees C with the following settings of 500 mw: PW = 10 msec and PRR < 35; or PW= 20 msec and PRR < 20 Hz. On the other hand, for the same irradiation conditions, the temperature rise on the surface of the root was always below 7 degrees C. However, the temperature increase became higher than 7 degrees C (on the surface of the root) in the case of P > 500 mw, PW > 50 msec and PRR > 10 Hz of root surface or a scanning speed of irradiation of 1 mm/sec for a linear irradiation of 4 mm. CONCLUSION: The KTP laser may be used safely without thermal damage to pulp and periodontal tissue with respect to the biologically acceptable previously described parameters.


Assuntos
Temperatura Corporal/fisiologia , Polpa Dentária/fisiologia , Lasers , Aplainamento Radicular , Humanos , Técnicas In Vitro , Fosfatos , Titânio
10.
Rev Stomatol Chir Maxillofac ; 105(4): 215-8, 2004 Sep.
Artigo em Francês | MEDLINE | ID: mdl-15510072

RESUMO

Histoplasmosis is an endemic mycosis. Histoplasma capsulatum, and duboisiï are the pathogenic agents in humans. The disease is reported as endemic in more than 30 countries. Three clinical forms are distinguished; acute, chronic and disseminated. Oral lesions may take on different clinical aspects which are often associated with disseminated histoplasmosis. Disseminated histoplasmosis is frequently diagnosed in immunocompromised hosts. High risk of mortality dictates rapid diagnosis and treatment.


Assuntos
Histoplasmose/patologia , Doenças da Boca/microbiologia , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Doença Aguda , Antifúngicos/uso terapêutico , Doença Crônica , Doenças Endêmicas , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Humanos , Hospedeiro Imunocomprometido , Doenças da Boca/diagnóstico , Doenças da Boca/tratamento farmacológico
11.
Rev Stomatol Chir Maxillofac ; 105(4): 223-6, 2004 Sep.
Artigo em Francês | MEDLINE | ID: mdl-15510074

RESUMO

Ameloblastic fibro-odontoma is a rare and benign tumor. It usually affects young patients. This report describes the case of a ten year old child presenting an asymptomatic and slow-growing tumor located in the posterior region of the mandible. The course was normal and no recurrence was found after simple enucleation of the tumor.


Assuntos
Neoplasias Mandibulares/patologia , Odontoma/patologia , Criança , Tecido Conjuntivo/patologia , Esmalte Dentário/patologia , Polpa Dentária/patologia , Dentina/patologia , Epitélio/patologia , Feminino , Seguimentos , Humanos
12.
Lasers Med Sci ; 19(1): 27-32, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15278724

RESUMO

To avoid the damage of periodontal tissues during laser irradiation of the root canal, the conditions of lasering must be carefully controlled. The aim of this study was to determine the safety parameters of the irradiation conditions during the use of a KTP-Nd:YAG laser in root canals. Root canals of 60 freshly extracted teeth were prepared (step-back technique) and filled with a photosensitiser (Acid Red 52). Different irradiation conditions [output power (P), pulse width (PW), pulse repetition rate (PRR, Hz)] were used. The laser beam was delivered by means of the KTP-Nd:YAG fibre tip with a beam spot-size diameter of 200 microm. The temperature increases were measured on the external apical third of the root surface using a thermocouple. The results showed that the temperature rise was always below 7 degrees C at the following laser settings: (1) single irradiation, P < or = 4 W, PW < or = 2.55 ms and PRR < or = 20 Hz; (2) repetitive irradiation series, five pulses of 1 s each, four resting times of 1 s each, P < or = 2.25 W, PW < or = 2.55 ms and PRR < or = 20 Hz. The use of resting times was necessary so as to avoid thermal cumulative effects. In these in vitro irradiation conditions, the use of the KTP-Nd:YAG laser in endodontics may be considered harmless for periodontal tissues.


Assuntos
Cavidade Pulpar/efeitos da radiação , Terapia a Laser , Humanos , Técnicas In Vitro , Lasers/efeitos adversos , Periodonto/fisiologia , Fármacos Fotossensibilizantes/farmacologia , Segurança , Temperatura
13.
J Clin Laser Med Surg ; 22(2): 99-104, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15165383

RESUMO

OBJECTIVE: To define the optimal parameters of KTP laser irradiation during a selective caries removal. MATERIALS AND METHODS: Twelve decayed human teeth, recently extracted were used. Their root canals were prepared for insertion of a thermocouple probe into the pulp chamber. The demineralized tissues were colored by Acid Red 52 before proceeding to different conditions of irradiation. RESULTS: Pulpal temperature increases (below 3 degrees C) were found under the following parameters with 15 sec of continuous lasing: 400 mWatts, 0.10-msec pulse width, PRR <50 Hz for efficient caries removal. A resting time average of 70 sec was necessary to allow pulp temperature to get back to its baseline. CONCLUSION: KTP laser can be used safely and without any pulp over-heating under certain irradiation conditions.


Assuntos
Temperatura Corporal , Cárie Dentária/cirurgia , Polpa Dentária/efeitos da radiação , Terapia a Laser/métodos , Segurança , Polpa Dentária/fisiologia , Humanos
14.
Rev Stomatol Chir Maxillofac ; 104(2): 77-9, 2003 Apr.
Artigo em Francês | MEDLINE | ID: mdl-12750624

RESUMO

INTRODUCTION: We present a prospective clinical study on use of tranexamic acid mouthwashes in patients taking oral anticoagulants and who have to undergo minor ambulatory oral surgery, without modifying their anticoagulant therapy. MATERIAL AND METHODS: Forty patients (18 men and 22 females) aged from 42 to 81 were studied from April 2000 to December 2002. All patients were under the same anticoagulant, vitamin K antagonist, (Sintrom) for different pathologies. The anticoagulant therapy was not modified neither before nor after surgery. More than 70 oral procedures were carried out under local anesthesia. The International Normalized Ratio of prothrombin time (INR) was<=4. Tranexamic acid 5% (Exacyl) mouthwashes were prescribed during and after surgery. RESULTS: All the patients were followed up during 2 weeks after surgery. There were no postoperative bleedings. DISCUSSION: Use of tranexamic acid mouthwashes under a specific protocol is an efficient, reliable and economic method in preventing postoperative bleeding in patients under oral anticoagulant therapy.


Assuntos
Anticoagulantes/administração & dosagem , Antifibrinolíticos/administração & dosagem , Assistência Odontológica para Doentes Crônicos/métodos , Hemorragia Bucal/prevenção & controle , Procedimentos Cirúrgicos Bucais , Hemorragia Pós-Operatória/prevenção & controle , Ácido Tranexâmico/administração & dosagem , Acenocumarol/administração & dosagem , Administração Oral , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares , Feminino , Humanos , Coeficiente Internacional Normatizado , Masculino , Pessoa de Meia-Idade , Antissépticos Bucais/uso terapêutico , Estudos Prospectivos
15.
J Biomed Mater Res ; 52(3): 567-71, 2000 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-11007626

RESUMO

The present study demonstrates the in vitro and in vivo adsorption of peroxidase onto titanium surfaces. Titanium foils (mean +/- SEM: 365 +/- 2 mm(2), n = 114) were incubated during 30 min with lactoperoxidase (4 mg in 5 mL 100 mM phosphate buffer pH 7). After 15 washings by H(2)O, titanium foils were incubated with o-phenylenediamine (6 mg/mL) and H(2)O(2) (7 mM) during 30 min. The reaction was then stopped by the addition of HCI 1M and the absorbance of the liquid phase was read on a spectrophotometer at 492 nm. In vitro adsorbed lactoperoxidase onto titanium surfaces was 0.70 +/- 0.05 ng/mm(2) (mean +/- SEM, n = 30). X-ray photoelectron spectroscopy confirmed the incorporation of protein nitrogen onto titanium surfaces: the nitrogen atomic percentage increased from 0.9 +/- 0.3 to 12.7 +/- 0.2% (n = 3) and from 3.7 +/- 0.1 to 14.4 +/- 0. 4% (n = 5) when titanium foils were incubated in the lactoperoxidase solution during 30 min and 24 h respectively. In vivo, oral peroxidases adsorbed on titanium healing abutments from 0.01 to 0.58 ng/mm(2) (n = 19) after 2 weeks in the oral environment.


Assuntos
Materiais Biocompatíveis/química , Dente Suporte , Lactoperoxidase/farmacocinética , Titânio/química , Adsorção , Adulto , Idoso , Análise de Variância , Microanálise por Sonda Eletrônica , Humanos , Lactoperoxidase/análise , Teste de Materiais , Pessoa de Meia-Idade , Boca/metabolismo , Projetos Piloto , Espectrofotometria , Propriedades de Superfície
16.
Ann Pathol ; 20(3): 190-5, 2000 May.
Artigo em Francês | MEDLINE | ID: mdl-10891711

RESUMO

Heat shock proteins (HSPs) are known to be increased in response to biological stress. Recently some authors described their presence in tumors. Our immunohistochemical investigations revealed the expression of HSP27, HSP70, HSP90 and HSP110 in most of benign tumors of salivary glands (33 cases). In the malignant tumors, the reaction was immunopositive for HSP70 and HSP90 in 13/17 cases; but HSP27 and HSP110 were only expressed in 5/17 cases. In conclusion HSPs were expressed less in malignant than in benign cells. These results suggest that the loss of some HSPs may be a possible sign of malignancy.


Assuntos
Proteínas de Choque Térmico HSP70/análise , Proteínas de Choque Térmico HSP90/análise , Proteínas de Choque Térmico , Proteínas de Neoplasias/análise , Neoplasias das Glândulas Salivares/química , Proteínas de Choque Térmico HSP110 , Proteínas de Choque Térmico HSP27 , Humanos , Técnicas Imunoenzimáticas , Chaperonas Moleculares
17.
Clin Oral Implants Res ; 11(2): 93-8, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11168199

RESUMO

The soft tissue response to clinically retrieved and decontaminated cover screws was evaluated in a rat model. The cover screws were cleaned by using citric acid, sterile water, hydrogen peroxide and CO2 laser alone or with a combination of these. In addition, decontaminated but not cleaned and unused cover screws were used as negative and positive controls, respectively. After cleaning the cover screws were implanted in the abdominal wall of the rat for 6 weeks. The thickness of the fibrous capsule and the number of macrophages within the capsule were measured by means of light microscopical morphometry. As compared to the negative control, CO2 laser on dry surface, CO2 laser + hydrogen peroxide and the positive control had statistically significant thinner fibrous capsules. As compared to the positive, only laser alone resulted in a similar tissue response. It is concluded that CO2 laser used alone or in combination with hydrogen peroxide may be used clinically for sufficient decontamination of titanium surfaces.


Assuntos
Descontaminação/métodos , Implantes Experimentais , Lasers , Titânio , Abdome , Animais , Ácido Cítrico , Descontaminação/instrumentação , Feminino , Fibrose , Peróxido de Hidrogênio , Inflamação , Ativação de Macrófagos , Masculino , Ratos , Ratos Sprague-Dawley , Estatísticas não Paramétricas
18.
Clin Implant Dent Relat Res ; 2(4): 190-202, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11359278

RESUMO

BACKGROUND: In clinical situations with peri-implant bone resorption, re-integration of the exposed implant surface is sometimes preferable, which requires a clean surface. Previous investigations have shown that cleaning of contaminated titanium surfaces using chemical and abrasive methods is difficult. PURPOSE: The aim of this investigation was to evaluate the efficacy of different combinations of chemical and physical methods (citric acid, hydrogen peroxide, and carbon dioxide [CO2] laser irradiation) for removal of contaminants and subsequent reconstruction of the surface oxide of intraorally contaminated titanium foils. MATERIALS AND METHODS: Commercially pure titanium foils (99.6%, 5 x 5 mm in size) were contaminated by placement on dentures in volunteering patients, simulating a peri-implantitis situation. The contaminated foils and clean control foils were treated by seven and six combinations of citric acid, hydrogen peroxide, and CO2 laser irradiation, respectively. The effect of the cleaning procedures was evaluated by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). RESULTS: The initial elemental composition of the contaminated foils was 70% carbon (C), 20% oxygen (O), 10% nitrogen (N), and only traces of titanium (Ti) (< 1%). One treatment proved to be more effective than the others: irradiations by 5-second cycles of superpulsed CO2 laser at a power of 7 W, 10-millisecond pulse width, and with an 80-Hz frequency on a wet surface, followed by repeated application of supersaturated citric acid for 30 seconds, each time followed by rinsing with ultrapure water until all tissue remnants had been removed. Finally, hydrogen peroxide of 10-mM concentration was added to the implant surface and evaporated by CO2 laser at the same settings. This treatment protocol resulted in 10% Ti, 45% O, 41% C, and 2 to 3% N, a composition comparable to that of unused foils: 9% Ti, 40% O, 48% C, and traces of N and chlorine (CI). X-ray photoelectron spectroscopy profiles showed that the thickness of the surface oxide was restored and even augmented with this protocol for treatment of contaminated titanium. CONCLUSION: A combination of citric acid, hydrogen peroxide, and CO2 laser irradiation seems to be effective for cleaning and reestablishment of the atomic composition and oxide structure of contaminated titanium surfaces.


Assuntos
Implantes Dentários , Detergentes/uso terapêutico , Contaminação de Equipamentos/prevenção & controle , Peróxido de Hidrogênio/uso terapêutico , Terapia a Laser , Oxidantes/uso terapêutico , Óxidos/química , Titânio/química , Carbono/análise , Dióxido de Carbono , Ácido Cítrico/uso terapêutico , Microanálise por Sonda Eletrônica , Humanos , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Nitrogênio/análise , Óxidos/efeitos da radiação , Oxigênio/análise , Propriedades de Superfície , Titânio/análise , Titânio/efeitos da radiação , Água/química
19.
Clin Oral Implants Res ; 10(1): 54-61, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10196790

RESUMO

The purpose of the present in vitro investigation was to measure temperature changes at the implant surface when using pulsed CO2 laser in a simulated implant surface decontamination protocol. Six threaded titanium implants were placed in a fresh resected pig mandible. A 4 x 4 mm defect was created buccally to each implant in order to expose the implant head and approximately 5 threads. Temperature changes were monitored by two thermocouples placed near the dehiscence and at the apical part of the implant. Several setting combinations of the CO2 laser with regard to output power, pulse width, pulse repetition rate and irradiation time were tested on dry and wet (distilled water) surfaces. Only minor temperature increases were measured when lasing wet titanium surfaces, while the temperature at dry surfaces exceeded the proposed thresholds for bone damage at clinically relevant settings. It is concluded that the CO2 laser when used on a wet implant surface in a pulsed mode at 8 W/10 ms/20 hz during 5 s induces a temperature increase of less than 3 degrees C. This would minimize the risk of temperature induced tissue damage as a result of lasing implant surfaces.


Assuntos
Descontaminação/instrumentação , Implantes Dentários , Lasers , Animais , Osso e Ossos/lesões , Dióxido de Carbono , Temperatura Alta , Lasers/efeitos adversos , Suínos , Temperatura , Titânio , Água/química
20.
Clin Oral Implants Res ; 9(3): 185-94, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10530133

RESUMO

The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.


Assuntos
Descontaminação/métodos , Implantes Dentários/microbiologia , Abrasão Dental por Ar , Ácido Cítrico , Remoção de Dispositivo , Microanálise por Sonda Eletrônica , Contaminação de Equipamentos , Humanos , Lasers , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Titânio , Ultrassom
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...