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2.
Int J Oral Maxillofac Surg ; 52(2): 245-254, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35778233

RESUMO

The displacement of dental implants into the maxillary sinus is increasingly reported and may lead to serious complications. Better knowledge of this condition could help clinicians improve their practice, but it is difficult to draw conclusions from the current literature. Therefore, a systematic review was performed to describe the main characteristics of dental implant displacement, as well as its management and temporal evolution over a 31-year period. This review was conducted according to the PRISMA methodology. The PubMed/Scopus electronic databases were searched to December 2021. Risk of bias was assessed using the Joanna Briggs Institute tools. A total of 73 articles reporting 321 patients with displaced dental implants were included. Implants located in the upper first molar site were the most frequently involved (23.7%). Displacement occurred mainly during the first 6 months after implant placement (62.6%). The majority became symptomatic (56.2%), most often due to maxillary sinusitis and/or oroantral communication (44.2%). The surgical approaches to remove displaced implants were the lateral approach (38.1%), the Caldwell-Luc approach (27.2%), and endoscopic nasal surgery (23.1%). This review highlights the importance of preventive measures: avoiding implant displacement by careful pre-implantation radiographic analysis, but also preventing infectious complications through early removal of the displaced implant (PROSPERO CRD42021279473).


Assuntos
Implantes Dentários , Sinusite Maxilar , Humanos , Seio Maxilar/diagnóstico por imagem , Seio Maxilar/cirurgia , Dente Molar , Endoscopia
3.
J Stomatol Oral Maxillofac Surg ; 123(1): 16-21, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-33596475

RESUMO

During the 2020 coronavirus pandemic, a lockdown was imposed in France during the first wave. An apparent decrease in incidence of cellulitis of odontogenic origin was noticed then. This study aimed to compare the incidence of cellulitis during this extraordinary period with the same period in 2018 and 2019, based on retrospective multicentric data. All maxillofacial surgery departments in French public hospitals were contacted. Responders were asked to include all patients admitted for the surgical drainage of a head and neck abscess of odontogenic origin during the first 2020 lockdown period, and in a similar time frame in 2018 and 2019 (control group), based on screening the French diagnostic and therapeutic classification of medical acts. We report a 44% significant nationwide decrease in the incidence of admissions for cellulitis. There were 187 patients in 2020 for 334 and 333 patients in 2018/2019 respectively. The reasons to explain this finding are hypothetical (organizational reasons leading to earlier management, patients' fear to seek for medical management, usual excess in surgical indications or concomitant decrease of non-steroidal anti-inflammatory drugs delivery). Whatever the explanation, it would be of great interest to find it out in order to improve the prevention of cellulitis.


Assuntos
COVID-19 , Celulite (Flegmão) , Celulite (Flegmão)/diagnóstico , Celulite (Flegmão)/epidemiologia , Celulite (Flegmão)/etiologia , Controle de Doenças Transmissíveis , Humanos , Estudos Retrospectivos , SARS-CoV-2
4.
Med Oral Patol Oral Cir Bucal ; 27(1): e42-e50, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34564684

RESUMO

BACKGROUND: Infective endocarditis (IE) is a rare and life-threatening disease. Cutaneous portal of entry (POE) is predominant for IE, but an oral POE is the second most frequent source. Thus looking for and treating an oral POE in IE patients is of critical importance in order to reduce the risk of IE relapse or recurrence. The objectives of this study were: 1) To reach a consensus on decision-making following the detection of an oral POE on cone-beam computed tomography (CBCT) while they were not identified using the current recommended approach in IE patients (oral examination and orthopantomogram: OPT). 2) To determine whether this consensus differs when regarding the microbiology of IE. MATERIAL AND METHODS: Twenty oral or maxillofacial surgeons participated to this Delphi study. The questionnaire was based on five radiological cases (OPT and matching CBCT) with two scenarios according to the objectives of detecting oral POE in an IE patient (curative in case of oral causative microorganism, and preventive if not) and different therapeutic approaches (surgical or conservative treatment, no treatment) for each of them. Consensus was defined as an agreement rate of ≥75%. RESULTS: The response rate was≥85%. After four rounds, consensus was achieved for all proposals. CBCT changed the decision-making of experts in four cases. In one case, the decision was influenced by the IE microbiology toward a more radical approach in case of oral causative microorganism. CONCLUSIONS: In IE patients, CBCT changed markedly the decision-making of experts by eradicating more oral POE than when using OPT. This could reduce the risk of IE relapse and recurrence.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Endocardite , Técnica Delphi , Assistência Odontológica , Endocardite/diagnóstico por imagem , Humanos , Radiografia Panorâmica
5.
Clin Oral Investig ; 26(2): 1667-1676, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34431002

RESUMO

OBJECTIVES: The primary aims of the present study were (1) to quantify and characterize anaphylactic type I reactions related to local anesthetics (LAs) drawing on the French Pharmacovigilance Database System over a 35-year period and (2) to focuse on reactions associated with dental procedures. The secondary aim was to infer an incidence rate in dental practice. MATERIALS AND METHODS: All cases of anaphylactic reactions were selected using the algorithmic Standardized MeDRA Query "anaphylactic reaction." For each reaction, comprehensive data were collected, in particular the severity of symptoms, risk factors for anaphylaxis, and allergy testing. Imputability was assessed and a crude incidence rate in dental practice was estimated. RESULTS: The first-line search identified 416 anaphylactic reactions, mostly of grade II (138) or III (240) severity. When restricted to dental practice, this number fell to 26 (grade I: 4; grade II: 10; grade III: 11; and grade IV: 1). Lidocaine was most often involved (81.49%) and mostly associated with anaphylactic reactions of grade II and III. Overall, 11 cases of fatal anaphylaxis were recorded, but no in dental practice. In dental practice, lidocaine was also the most frequently involved LA (57.69%). CONCLUSIONS: All these findings highlight the very low incidence of type I-IgE-mediated reactions to LA, particularly in dental practice. The incidence rate of LA anaphylctic episodes in dental practice was estimated as 0.0261 anaphylactic episodes per million LA cartridges. CLINICAL RELEVANCE: True anaphylactic reactions to LAs do occur and may justify a thorough investigation in dental practice.


Assuntos
Anafilaxia , Anafilaxia/induzido quimicamente , Anafilaxia/epidemiologia , Anestésicos Locais/efeitos adversos , Humanos , Incidência , Lidocaína , Estudos Retrospectivos
6.
Eur J Clin Microbiol Infect Dis ; 39(7): 1295-1303, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32062724

RESUMO

The aim of this survey was to describe the attitudes and self-reported practices of French dentists towards antibiotic use and resistance and to compare practices with national guidelines. A nationwide cross-sectional internet-based survey was conducted among the 41,800 French dentists. The online questionnaire was distributed through professional networks from April 2017 to April 2018. Seven-hundred seventy-five dentists participated but only 455 questionnaires were complete enough to be included in the analyses. Amoxicillin was the most frequently prescribed antibiotic (65.8%, 1783/2711), followed by spiramycin + metronidazole fixed-dose combination (11.6%, 312/2711) and amoxicillin-clavulanic acid (10.3%, 279/2711). The main indications for use were abscess (349/423, 82.5%), cervicofacial cellulitis (74.2%, 314/423), and pericoronitis (58.6%, 239/408). Most dentists (90.5%, 381/421) considered that antibiotic resistance is of concern but only half of them (56.3%, 238/423) felt adequately informed about antibiotic use. Many dentists did not comply with the national guidelines: the majority of them declared inappropriate antibiotic prescriptions for 11/17 clinical situations. They did not prescribe antibiotics for 5/6 clinical situations requiring prophylaxis. They reported that the publication of clinical guidelines is the main factor influencing their prescriptions (71.0%, 299/421). They wished to receive regular updates of national guidelines in the form of practical sheets (93.0%, 172/185). French dentists should urgently be targeted by antibiotic stewardship initiatives.


Assuntos
Antibacterianos/uso terapêutico , Odontólogos/estatística & dados numéricos , Resistência Microbiana a Medicamentos , Adulto , Gestão de Antimicrobianos , Atitude do Pessoal de Saúde , Estudos Transversais , Feminino , França , Fidelidade a Diretrizes , Pesquisas sobre Atenção à Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Padrões de Prática Médica , Prescrições/estatística & dados numéricos
7.
Int J Cardiol ; 299: 222-227, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31327512

RESUMO

BACKGROUND: To prevent infective endocarditis (IE), with the exception of the United Kingdom, antibiotic prophylaxis (AP) is recommended in patients with predisposing cardiac conditions (PCCs) worldwide. To conclude on the relevance of this strategy, how the current guidelines are applied is a crucial point to investigate. The first aim of this study was to assess cardiologists' implementation of the current guidelines. The secondary objective was to identify specific areas where the training and knowledge of French cardiologists could be improved. METHODS: A national online survey was carried out among the 2228 cardiologist members of the French Society of Cardiology. RESULTS: The high risk PCCs for which IE AP is recommended were correctly identified by the vast majority of the respondents so that IE AP is mostly prescribed correctly in such patients. But only 12% identified all the right indications for IE AP according to 13 predefined PCCs (3 at high-risk, 6 at moderate-risk and 4 at low-risk of IE) so that some IE AP misuses are recorded, overprescription in particular. Only 47% prescribed the proper amoxicillin schedule and only 15% prescribed the appropriate clindamycin schedule in cases with penicillin allergy. CONCLUSION: This study evidenced relevant areas where the training of cardiologists could be improved such as knowledge of the risk of IE for certain PCCs and some common invasive dental procedures. Cardiologists' knowledge should be improved before any conclusion can be drawn on the relevance of this AP strategy and its influence on IE incidence.


Assuntos
Antibioticoprofilaxia/normas , Cardiologistas/normas , Endocardite Bacteriana/epidemiologia , Endocardite Bacteriana/prevenção & controle , Guias de Prática Clínica como Assunto/normas , Inquéritos e Questionários , Adulto , Antibioticoprofilaxia/métodos , Endocardite/epidemiologia , Endocardite/prevenção & controle , Feminino , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
8.
J Stomatol Oral Maxillofac Surg ; 121(3): 308-311, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31055091

RESUMO

Gingival enlargements (GEs) can be caused by local, systemic diseases or drugs. Three molecules can be responsible of GEs: ciclosporin, phenytoin and calcium channel blockers (CCBs). We report the case of a 56-year-old male treated by Amlodipine, a CCB, for hypertension for many years and who recently developed a severe GE affecting both mandibular and maxillary arches inducing dental malposition. The histological examination showed non-specific inflammation with a predominance of lymphocytes. Amlodipine was suspected and suspended in agreement with his physician. One month later, the enlargement significantly reduced but GE was so severe and dental malposition so marked that all the teeth but the canines were extracted. No recurrence was noted one year later. This exceptional case should encourage every practitioner to be vigilant with patient treated with CCBs and their potential side effects and consequences.


Assuntos
Anlodipino/efeitos adversos , Crescimento Excessivo da Gengiva/induzido quimicamente , Crescimento Excessivo da Gengiva/diagnóstico , Crescimento Excessivo da Gengiva/tratamento farmacológico , Bloqueadores dos Canais de Cálcio/efeitos adversos , Bloqueadores dos Canais de Cálcio/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade
9.
Med Oral Patol Oral Cir Bucal ; 24(3): e296-e304, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31011140

RESUMO

BACKGROUND: One of the major reasons to stop antibiotic prophylaxis (AP) to prevent infective endocarditis (IE) in the United Kingdom but not in the rest of the world was that it would result in more deaths from fatal adverse drug reactions (ADRs) than the number of IE deaths. The main aim of this study was to quantify and describe the ADRs with amoxicillin or clindamycin for IE AP. The second aim was to infer a crude incidence of anaphylaxis associated with amoxicillin for IE AP. STUDY DESIGN: The Medical Dictionary for Regulatory Activities (MedDRA) was used to group ADRs for IE AP using the broad Standardized MedDRA Queries "Anaphylactic reaction, Amoxicillin, Clindamycin, Clostridium Difficile infection" to the French Pharmacovigilance Database System. From this first-line collection, we selected all cases occurring for IE AP and ultimately, the cases for IE AP for a dental procedure. Then, each case was analyzed. RESULTS: Of 11639 first-line recorded ADRs, 100 were for IE AP but no fatal anaphylaxis to amoxicillin or clindamycin and no C. difficile infection associated with clindamycin were identified. Only 17 cases of anaphylaxis to amoxicillin related to dental procedures were highlighted. The estimation of the crude incidence rate of anaphylaxis associated with amoxicillin for IE AP for invasive dental procedure was 1/57 000 (95% CI 0.2-0.6). CONCLUSIONS: Fatal or severe ADRs with amoxicillin or clindamycin is not a rational argument to stop IE AP before invasive dental procedures.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Endocardite Bacteriana , Endocardite , Antibioticoprofilaxia , França , Humanos
10.
Eur J Dent Educ ; 22(2): e261-e268, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-28833993

RESUMO

INTRODUCTION: Any dental surgeon may be faced with a critical life-threatening emergency situation. In our university, all students in dentistry receive a standard course on emergency first aid. The aim of this prospective, comparative, single-centre study was to determine whether additional training on a high-fidelity patient simulator would improve student performance. METHODS: After approval by an Ethical Committee and written informed consent, the students of the Simulation group (n=42) had full-scale high-fidelity training on a patient simulator SimMan 3G™ (3 hours by six students). They participated in pairs in two scenarios (airway obstruction, seizures, allergies, vasovagal syncope, asthma, chest pain). The first scenario was simple, and the second was a progression to cardiac arrest. Three months later, the Simulation group and the Control group (n=42) participated in a test session with two scenarios. The primary end point was the score at the test session (with a standardised scoring grill, direct observation and audio-video recording). Data were median and 25%-75% percentiles. RESULTS: High-fidelity training strongly improved the score on the test obtained by the students of the Simulation group (146 [134-154]) which was much higher (P<.0001) than in the Control group (77 [67-85]). Technical as well as non-technical skills components of the scores were improved. In addition, performances of the Simulation group were increased between the training and the test. Simulation session was very positively assessed by the students. CONCLUSIONS: The results support the systematic introduction of training to critical life-threatening emergency situations on high-fidelity patient simulators the dentistry curriculum. The impact on clinical practice in the dental office remains to be assessed.


Assuntos
Competência Clínica , Educação em Odontologia/métodos , Tratamento de Emergência , Treinamento com Simulação de Alta Fidelidade/métodos , Simulação de Paciente , Emergências , França , Humanos , Estudos Prospectivos , Estudantes de Odontologia
11.
J Stomatol Oral Maxillofac Surg ; 118(3): 151-155, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28365395

RESUMO

INTRODUCTION: Oral melanocytic nevi (OMNs) are uncommon benign melanocytic tumors, histologically similar to their cutaneous counterparts. The aim of this study was twofold: to contribute to the epidemiology with a literature review with the first Spanish series of OMNs, and to report on clinicopathological, immunohistochemical and demographic findings. MATERIALS AND METHODS: A retrospective analysis of cases attended over the period 1999-2010 was carried out using data drawn from the pathology unit files at two public hospitals in the Spanish region of Andalusia, serving between them a population of 823.614 inhabitants (11%). RESULTS: Ten cases of OMNs were retrieved, accounting for 0.18% of the total 5499 oral biopsies performed over the period. The female-to-male ratio was 1.5:1; mean patient age was 30. The palate was the most common location (70%). Relative frequencies of histologic types were as follows: subepithelial (40%), common blue (30%), compound (20%) and junctional (10%). Immunohistochemical examination showed strong S-100 protein expression, variable reactivity to HMB-45 and high c-Kit expression by junctional melanocytes. Ki-67 was ≤3 in all cases. CONCLUSIONS: Although this first clinicopathologic analysis of OMNs reported in Spain was based on a small patient series, the results are in line with those reported in larger series and additionally provide new demographic data. Since OMNs and early melanomas are usually detected at routine dental examination, detailed oral exploration should always be performed, and in case of doubt a biopsy should be taken to ensure an accurate diagnosis.


Assuntos
Neoplasias Bucais/diagnóstico , Neoplasias Bucais/metabolismo , Nevo Pigmentado/diagnóstico , Nevo Pigmentado/metabolismo , Adolescente , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/epidemiologia , Neoplasias Bucais/patologia , Nevo Pigmentado/epidemiologia , Nevo Pigmentado/patologia , Estudos Retrospectivos , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Adulto Jovem
13.
J Periodontol ; 80(12): 2035-44, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19961387

RESUMO

BACKGROUND: Estrogen withdrawal causes marked bone loss in the appendicular skeleton but slightly affects mandibular cancellous bone; in contrast, little is known of its effects on alveolar wall turnover associated with tooth drift. In this study, we assessed short-term changes in alveolar wall turnover after an ovariectomy and compared it to other bone sites exhibiting different levels of turnover. METHODS: Forty Sprague-Dawley rats were ovariectomized or sham operated. Right mandibles and femurs were processed without demineralization for bone histomorphometry in three different sites: the alveolar wall around the first molar buccal root, apical interradicular bone, and femoral metaphysis. Bone changes were assessed 14 and 28 days after the ovariectomy. Data were compared using non-parametric statistics. RESULTS: At 14 days, on the resorption side of the alveolar wall, resorption parameters were higher in the ovariectomized rats (P <0.01), whereas the formation was lower (P <0.05); on the formation side, the daily mineral apposition rate increased (P <0.01). The root resorption was higher in ovariectomized rats (P <0.05). In the periodontal ligament, the numbers of osteoclast precursors were significantly higher. At 28 days, the drift slowed down in both the sham and ovariectomized groups. The ovariectomy had no effect on interradicular bone turnover, whereas bone loss and numbers of osteoclasts were strongly increased in the femur as soon as 14 days after the ovariectomy. CONCLUSIONS: Estrogen withdrawal had transient repercussions on alveolar wall turnover. The different reactivities of the three envelopes studied suggest that a response to an ovariectomy in the short term is related to initial basal turnover.


Assuntos
Remodelação Óssea/fisiologia , Estrogênios/deficiência , Ovariectomia , Alvéolo Dental/patologia , Fosfatase Ácida/análise , Processo Alveolar/patologia , Animais , Antígenos CD/análise , Antígenos de Diferenciação Mielomonocítica/análise , Biomarcadores/análise , Reabsorção Óssea/patologia , Feminino , Fêmur/patologia , Isoenzimas/análise , Mandíbula/patologia , Dente Molar/patologia , Osteoclastos/patologia , Osteogênese/fisiologia , Ligamento Periodontal/patologia , Ligante RANK/análise , Ratos , Ratos Sprague-Dawley , Reabsorção da Raiz/patologia , Fosfatase Ácida Resistente a Tartarato , Fatores de Tempo
14.
Presse Med ; 34(15): 1073-7, 2005 Sep 10.
Artigo em Francês | MEDLINE | ID: mdl-16334883

RESUMO

INTRODUCTION: The latest generations of bisphosphonates constitute a major advance in the management of disorders including Paget's disease, osteoporosis, and osteolytic bone tumors. Recent reports describe numerous cases of osteonecrosis of the jaw in patients treated with bisphosphonates. Some of these reports mention predisposing factors, including surgical procedures, chemotherapy, and radiotherapy. CASES: In the past 12 months, we have observed and treated 9 cases of maxillary osteonecrosis, which we present summarily. DISCUSSION: Some of our cases (3 of 9), like many of those described in literature, do not present predisposing factors. The osteonecrosis may thus be due mainly to the effect of bisphosphonates that, by blocking bone remodeling, may cause excessive bone mineralization. If this hypothesis is confirmed, these cases of osteonecrosis may be due to excess doses. Better dose adjustment should thus help prevent this complication.


Assuntos
Conservadores da Densidade Óssea/efeitos adversos , Difosfonatos/efeitos adversos , Doenças Maxilomandibulares/induzido quimicamente , Osteonecrose/induzido quimicamente , Adolescente , Idoso , Idoso de 80 Anos ou mais , Conservadores da Densidade Óssea/administração & dosagem , Difosfonatos/administração & dosagem , Feminino , Humanos , Imidazóis/administração & dosagem , Imidazóis/efeitos adversos , Doenças Maxilomandibulares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Osteonecrose/diagnóstico por imagem , Pamidronato , Radiografia Panorâmica , Cintilografia , Fatores de Tempo , Tomografia Computadorizada por Raios X , Ácido Zoledrônico
15.
Rev Stomatol Chir Maxillofac ; 106(3): 157-65, 2005 Jun.
Artigo em Francês | MEDLINE | ID: mdl-15976703

RESUMO

Bone graft healing involves an invasive process where vessels and cells penetrate the graft material to enable neoformation of bone. The origin of the material and its intrinsic properties and morphology are factors which affect its resorption and replacement. The first step involve formation of bone via the osteoconductive properties of the graft. For autologous bone, graft resorption enables secondarly release of preserved bone proteins, favoring a process of osteo-induction which contributes to remodelling and graft replacement by neoformed bone.


Assuntos
Transplante Ósseo/fisiologia , Remodelação Óssea/fisiologia , Reabsorção Óssea/fisiopatologia , Humanos , Osteogênese/fisiologia , Cicatrização/fisiologia
17.
Bone ; 30(1): 131-6, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11792575

RESUMO

Ovariectomy rapidly induces strong osteoclast differentiation, leading to a marked loss of cancellous bone in the rat appendicular skeleton. As we found that histamine inhibition prevented periosteal bone resorption in rats, we tested the hypothesis that cimetidine, an H(2) receptor antagonist, prevents the osteoclastic burst and subsequent trabecular bone loss in this setting. Forty female Sprague-Dawley rats were ovariectomized (ovx) or sham-operated. Rats from each group received daily intramuscular injections of cimetidine (125 mg/kg per day) or vehicle. The animals were killed 14 days after surgery, and their femora were processed for morphometry. Cimetidine had no effect on serum estradiol levels in the control and ovx rats. BV/TV was reduced by 36% in the ovx rats, and by 10% in the cimetidine treated rats (p < 0.01). Tb.N and Tb.Wi were significantly reduced by 30% in the ovx rats and by 15% ovx-treated ones. OcS/BS did not change in the treated ovx rats, but increased 3.7-fold in the untreated ovx ones (p < 0.001). The N.Oc/TBPm increased markedly in the ovx rats (2.6-fold, p < 0.0001 vs. controls), but only slightly in the cimetidine-treated animals (+18%, p < 0.05 vs. controls), with a significant difference between the cimetidine-treated and -untreated ovx animals (p < 0.001). Cimetidine had no effect on these parameters in sham-operated animals. These results show that histamine inhibition by an H(2) receptor antagonist partially prevents the consequences of castration on cancellous bone, possibly by an action on osteoclast differentiation. Interestingly, cimetidine had no effect on basal resorption along trabecular bone. Histamine inhibition by H(2) blockers warrants further investigation in this model of osteopenia.


Assuntos
Doenças Ósseas Metabólicas/prevenção & controle , Reabsorção Óssea/prevenção & controle , Cimetidina/farmacologia , Antagonistas dos Receptores H2 da Histamina/farmacologia , Osteoclastos/efeitos dos fármacos , Animais , Doenças Ósseas Metabólicas/etiologia , Doenças Ósseas Metabólicas/patologia , Doenças Ósseas Metabólicas/fisiopatologia , Reabsorção Óssea/etiologia , Reabsorção Óssea/patologia , Reabsorção Óssea/fisiopatologia , Diferenciação Celular/efeitos dos fármacos , Tamanho Celular/efeitos dos fármacos , Feminino , Histamina/fisiologia , Osteoclastos/patologia , Osteoclastos/fisiologia , Ovariectomia/efeitos adversos , Ratos , Ratos Sprague-Dawley
18.
Calcif Tissue Int ; 68(5): 297-303, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11683537

RESUMO

We previously reported that mast cells accumulate in the tibia bone marrow of ovariectomized (OVX) rats. In this study, the timing of mast cell accumulation and osteoclast generation were compared to determine whether or not mast cell accumulation preceded osteoclast recruitment after ovariectomy. This may be significant because of the number of cytokines released by mast cells that are potentially active on resorption. Sprague-Dawley rats (120) aged 12 weeks were OVX or sham-operated, and killed on days 4, 7, 14, 28, and 56 postsurgery. Ten additional intact rats were used as baseline controls. Ovariectomy was confirmed by a sharp and sustained fall in serum estradiol. The loss in trabecular bone volume (BV/TV) began on day 7, reaching 80% on day 56 (P < 0.001 vs baseline controls). The number of osteoclasts (N.OC/TBPm) increased in the OVX rats between days 4 and 7 (+130%; P < 0.001), and continued rising to day 28. During the next month, it decreased greatly (-63%, P < 0.001 on day 56 vs day 28). In the sham-treated rats, few mast cells were scattered in the bone marrow (1.9 cells/mm2 in the baseline controls). Their number fluctuated during the experimental period, but at each time-point it was lower than in the OVX rats. They were predominantly (90%) of the mucosal subtype. In the OVX rats, their number doubled between days 4 and 14 (P < 0.001), reached 8.6 cells/mm2 on day 28 (a 5.4-fold increase compared with day 4 OVX rats), and plateaued for the next 4 weeks. OVX had no effects on mast cell subtypes. In conclusion, mast cell accumulation and osteoclast differentiation are precocious and concomitant; this does not support a direct role for mast cells in osteoclast recruitment. Rather, the two cell populations may derive from a common precursor or be targeted simultaneously by estrogen depletion through common stimulator(s). Mast cell hyperplasia appears to be a significant, and usually unknown, manifestation of ovariectomy in the bone marrow environment.


Assuntos
Células da Medula Óssea/fisiologia , Mastócitos/fisiologia , Ovariectomia , Animais , Peso Corporal , Células da Medula Óssea/citologia , Contagem de Células , Modelos Animais de Doenças , Estradiol/sangue , Feminino , Fêmur/citologia , Mastócitos/citologia , Osteoclastos/citologia , Osteoclastos/fisiologia , Osteoporose/fisiopatologia , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
19.
Exp Physiol ; 86(3): 373-9, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11429655

RESUMO

Prostaglandins (PGs) promote both bone resorption and formation in vitro and in vivo. In a synchronised model of bone remodelling, indomethacin, an inhibitor of PG synthesis, given from the start of the sequence, transiently impaired bone resorption. In this study we further explored the involvement of PGs in this model by treating rats with indomethacin (7.5 mg x kg(-1) x day(-1)) for 6 days from the peak of resorption (day 4 after activation in this model) or during reversal (day 6 after activation). In rats treated from day 4, the resorption surface (Oc.S/BS) and the number of osteoclasts (N.Oc/BPm) were higher on day 10 (+69 %, P < 0.01, and +60 %, P < 0.02 compared with controls, respectively); no effect on cell resorptive activity was observed. The bone formation surface (OS/BS) was reduced (-50 %, P < 0.01). The inactive surface (In/BS) was not modified. In rats treated from day 6, the Oc.S/BS was also higher than in controls (P < 0.02), as was the N.Oc/BPm (P < 0.05). Osteoclast activity appeared to be increased, as the osteoclast-bone interface was larger (P < 0.02), but the mean lacuna area was reduced (-23 %, P < 0.05). Bone formation was also strongly affected: the OS/BS was decreased (-66 %, P < 0.01), as was the osteoid seam thickness (-24 %, P < 0.05). The In/BS was increased 1.5-fold (P < 0.05). These data indicate that PGs intervene at various stages of this remodelling sequence, as both resorption and formation were affected by indomethacin. Although resorption resumed in the two treatment groups despite treatment continuation, the timing of treatment was clearly important. Only inhibition of PG synthesis at the peak of resorption delayed all phases of the remodelling sequence. In contrast, inhibition during the reversal phase prevented activation of a significant part of the bone surface usually involved at this stage of remodelling; this treatment schedule reduced the resorptive capacity of the system, and depressed osteoblast activity.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Remodelação Óssea/efeitos dos fármacos , Indometacina/farmacologia , Mandíbula/fisiologia , Animais , Masculino , Mandíbula/citologia , Mandíbula/efeitos dos fármacos , Modelos Animais , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/fisiologia , Prostaglandinas/fisiologia , Ratos , Ratos Wistar , Extração Dentária
20.
Cells Tissues Organs ; 164(1): 23-9, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10940670

RESUMO

We have previously shown that mast cells (MC) may act as accessory cells of bone resorption in a synchronized model of resorption. The aim of this study was to verify whether bone marrow MC accumulated during the phase of rapid osteopenia development in estrogen-deprived rats. Sprague-Dawley rats, 90 days old, were subjected to bilateral ovariectomy (OVX) or sham surgery (controls). Bone histomorphometry was performed in the proximal tibia metaphysis. Thirty days after surgery, serum estradiol had dropped (p < 0.002), and osteopenia was well established in the OVX rats (trabecular bone volume decreased by 69%, p < 0.0001). The indices of bone resorption were strongly modified: the number (p < 0.0001) and individual activity (p < 0.001) of the trabecular osteoclasts were prominently increased in the OVX rats. Ovariectomy resulted in a dramatic increase in the number of bone marrow MC (p < 0.0001), 97% of which were of the mucosal subtype. These results show that MC accumulate concomitantly with osteoclast generation in estrogen-deficient rats. Although the biological significance of this MC increase is unknown from these results, we hypothesize that MC might play a role in ovariectomy-induced bone loss similar to that they we previously proposed in a mechanically activated model of resorption.


Assuntos
Células da Medula Óssea/fisiologia , Mastócitos/fisiologia , Osteoporose/fisiopatologia , Animais , Peso Corporal , Células da Medula Óssea/citologia , Contagem de Células , Modelos Animais de Doenças , Estradiol/sangue , Feminino , Mastócitos/citologia , Osteoclastos/citologia , Osteoclastos/fisiologia , Ovariectomia , Ratos , Tíbia/citologia
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