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1.
Psychiatry Res ; 337: 115953, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38763079

RESUMO

BACKGROUND: Bipolar disorder (BD) is a severe psychiatric disease and part of its burden is related to the high rates of lifetime psychiatric comorbidity (PC), with diagnostic, therapeutic, and prognostic implications. METHODS: Registered in PROSPERO (CRD42021282356). Meta-analyses were performed, searching for relevant papers published from 1993 to 2022 in Medline/PubMed (including E-Pub Ahead of Print), Embase, Cochrane Library (Central), PsycINFO, Scopus, Web of Science and via hand-searching, without language restrictions. 12.698 studies were initially identified, 114 of which were ultimately chosen based on the eligibility criteria. We performed two meta-analyses (prevalence and risk ratio) of mental health conditions among subjects with BD and then conducted a comprehensive examination of moderator effects using multivariable meta-regression models for moderators identified as significant in the univariable analysis. FINDINGS: Overall PC prevalence of at least one disorder was 38.91 % (95 % CI 35.24-42.70) and the most frequent disorders were: anxiety (40.4 % [34.97-46.06]), SUD (30.7 % [23.73-38.73]), ADHD (18.6 % [10.66-30.33]) and Disruptive, impulse-control and conduct disorder (15 % [6.21-31.84). The moderators with higher association with individual prevalences were UN's Human Development Index (HDI), female gender, age, suicide attempt, and age at onset (AAO). INTERPRETATION: It becomes evident that the prevalence of PC among individuals with BD is notably high, surpassing rates observed in the general population. This heightened prevalence persists despite significant heterogeneity across studies. Consequently, it is imperative to redirect clinical focus towards comprehensive mental health assessments, emphasizing personalized and routine screening. Additionally, there is a pressing need for the enhancement of public policies to create a supportive environment for individuals with BD, ensuring better therapeutic conditions and sustained assistance. By addressing these aspects, we can collectively strive towards fostering improved mental health outcomes for individuals with BD.


Assuntos
Transtorno Bipolar , Comorbidade , Humanos , Transtorno Bipolar/epidemiologia , Prevalência , Transtornos Mentais/epidemiologia , Transtornos de Ansiedade/epidemiologia
3.
J Maxillofac Oral Surg ; 21(4): 1393-1396, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36896067

RESUMO

Background: Maxillofacial injuries are very frequent in the sports environment. Padel is a new sport of Mexican origin, very popular in Mexico, Spain, and Italy, but with a rapid spread in Europe and other continents. Aims: The aim of this article is to report our experience of 16 patients with maxillofacial injuries that occurred during padel matches in 2021. All these injuries occurred due to the racket bouncing against the glass of the padel court. The bounce of the racquet is given either because the player was trying to hit the ball near the glass or by throwing the racket against the glass for an act of nervousness. Methods: We carried out a literature review about sports traumas, and we calculated the possible force with which the racket, once bounced off the glass, hits the players' faces. Results and Conclusions: The racket, bouncing off the glass wall, arrives with a specific force in the face of the player who threw the racket, being able to cause skin wounds, injuries, and fractures mainly at the level of the dentoalveolar junction.

4.
Acta Psychiatr Scand ; 142(6): 476-485, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32936930

RESUMO

OBJECTIVE: We set forth to build a prediction model of individuals who would develop bipolar disorder (BD) using machine learning techniques in a large birth cohort. METHODS: A total of 3748 subjects were studied at birth, 11, 15, 18, and 22 years of age in a community birth cohort. We used the elastic net algorithm with 10-fold cross-validation to predict which individuals would develop BD at endpoint (22 years) at each follow-up visit before diagnosis (from birth up to 18 years). Afterward, we used the best model to calculate the subgroups of subjects at higher and lower risk of developing BD and analyzed the clinical differences among them. RESULTS: A total of 107 (2.8%) individuals within the cohort presented with BD type I, 26 (0.6%) with BD type II, and 87 (2.3%) with BD not otherwise specified. Frequency of female individuals was 58.82% (n = 150) in the BD sample and 53.02% (n = 1868) among the unaffected population. The model with variables assessed at the 18-year follow-up visit achieved the best performance: AUC 0.82 (CI 0.75-0.88), balanced accuracy 0.75, sensitivity 0.72, and specificity 0.77. The most important variables to detect BD at the 18-year follow-up visit were suicide risk, generalized anxiety disorder, parental physical abuse, and financial problems. Additionally, the high-risk subgroup of BD showed a high frequency of drug use and depressive symptoms. CONCLUSIONS: We developed a risk calculator for BD incorporating both demographic and clinical variables from a 22-year birth cohort. Our findings support previous studies in high-risk samples showing the significance of suicide risk and generalized anxiety disorder prior to the onset of BD, and highlight the role of social factors and adverse life events.


Assuntos
Transtornos de Ansiedade/psicologia , Transtorno Bipolar/diagnóstico , Depressão/psicologia , Vigilância da População , Medição de Risco/métodos , Algoritmos , Transtornos de Ansiedade/epidemiologia , Transtorno Bipolar/epidemiologia , Transtorno Bipolar/psicologia , Estudos de Coortes , Depressão/epidemiologia , Feminino , Humanos , Aprendizado de Máquina , Masculino , Abuso Físico , Valor Preditivo dos Testes , Fatores Socioeconômicos , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Suicídio/estatística & dados numéricos , Adulto Jovem
5.
Forensic Sci Int ; 315: 110434, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32758788

RESUMO

BACKGROUND: Point-of-collection testing (POCT) devices for psychoactive substance detection through oral fluid samples are used in several countries for traffic enforcement. However, the reported reliability of such devices is quite heterogeneous among studies, and evaluating and comparing their analytical performance is of paramount importance to guide enforcement policies. AIM: To evaluate the analytical reliability of four POCT devices for the detection of cocaine and cannabinoids using oral fluid samples of Brazilian drivers. METHOD: A total of 168 drivers were recruited during standard roadblockfI procedures in Southern Brazil. Subjects were screened using one of the following POCT devices: the DDS2™, the DOA MultiScreen™, the Dräger Drug Test 5000™ and the Multi-Drug Multi-Line Twist Screen Device™ (MDML). Results of the screening tests were compared with chromatographic analyses in order to obtain the reliability parameters. RESULTS: The prevalence of confirmed positive samples for cocaine and cannabinoids were 9 % and 4.4 %, respectively. For cocaine, three POCT devices (MDML™, Dräger DrugTest 5000™, DOA MultiScreen™) showed good reliability, greater than 80 % of performance measures, using guidelines for research on drugged driving published by Walsh et al. (cutoff 10ng/mL). However, for cannabinoids, the devices had low reliability-only Dräger DrugTest 5000™ had good performance using cut-offs proposed by Walsh et al. (cutoff 2ng/mL). CONCLUSION: We observed a high prevalence of drivers testing positive for cocaine and cannabinoids. Most devices achieved good reliability performance for cocaine detection using cutoffs proposed by Walsh et al. or using the device's own cutoff. Instead, the reliability for cannabinoid detection obtained the desired parameters in just one device using cut-offs proposed by Walsh et al. and its own cutoff. Difficulties in detecting cannabinoids at the roadside should be better evaluated before the implementation of such tests.


Assuntos
Canabinoides/análise , Cocaína/análise , Dirigir sob a Influência , Saliva/química , Detecção do Abuso de Substâncias/métodos , Adolescente , Adulto , Brasil , Feminino , Humanos , Drogas Ilícitas/análise , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto Jovem
7.
Br J Oral Maxillofac Surg ; 58(6): 692-697, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32414539

RESUMO

Maxillofacial departments in 23 surgical units in Italy have been increasingly involved in facing the COVID-19 emergency. Elective surgeries have been progressively postponed to free up beds and offer human and material resources to those infected. We compiled an inventory of 32 questions to evaluate the impact of the SARS-COV2 epidemic on maxillofacial surgery in 23 selected Italian maxillofacial departments. The questionnaire focused on three different aspects: the variation of the workload, showing both a reduction of the number of team members (-16% among specialists, -11% among residents) due to reallocation or contamination and a consistent reduction of elective activities (the number of outpatient visits cancelled during the first month of the COVID-19 epidemic was about 10 000 all over Italy), while only tumour surgery and trauma surgery has been widely guaranteed; the screening procedures on patients and physicians (22% of maxillofacial units found infected surgeons, which is 4% of all maxillofacial surgeons); and the availability of Personal Protective Equipment, is only considered to be partial in 48% of Maxillofacial departments. This emergency has forced those of us in the Italian health system to change the way we work, but only time will prove if these changes have been effective.


Assuntos
Betacoronavirus , Infecções por Coronavirus , Pandemias , Pneumonia Viral , Cirurgia Bucal , COVID-19 , Infecções por Coronavirus/epidemiologia , Humanos , Itália/epidemiologia , Pneumonia Viral/epidemiologia , SARS-CoV-2
8.
Bull Environ Contam Toxicol ; 98(2): 190-195, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28025689

RESUMO

This study investigated to what extent a single exposure to low doses of ionizing radiation can induce genotoxic damage in irradiated adult zebrafish (Danio rerio) and its non-irradiated F1 progeny. Four groups of adult zebrafish were irradiated with a single dose of X-rays at 0 (control), 100, 500 and 1000 mGy, respectively, and couples of each group were allowed to reproduce following irradiation. Blood of parental fish and whole-body offspring were analysed by the comet assay for detection of DNA damage. The level of DNA damage in irradiated parental fish increased in a radiation dose-dependent manner at day 1 post-irradiation, but returned to the control level thereafter. The level of DNA damage in the progeny was directly correlated with the parental irradiation dose. Results highlight the genotoxic risk of a single exposure to low-dose ionizing radiation in irradiated individuals and also in its non-irradiated progeny.


Assuntos
Exposição à Radiação , Radiação Ionizante , Peixe-Zebra/genética , Animais , Ensaio Cometa , Dano ao DNA , Relação Dose-Resposta à Radiação , Raios gama , Reprodução
9.
Case Rep Med ; 2016: 9168429, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27999596

RESUMO

Pseudoaneurysm of the internal maxillary artery due to a traumatic event is a rare condition. Pseudoaneurysms are usually directly produced by arteries break with extravasation of blood. The compressed perivascular tissue forms the wall of aneurysmal sac. Then, this sac gradually expands and can be damaged. It is rare to see pseudoaneurysms of IMA. They are usually associated with fracture of the neck of the mandible. To the best of our knowledge the pseudoaneurysm of the internal maxillary artery related to maxillofacial trauma is an event extremely rare in the literature and if not quickly managed can lead to the patient's death. This case underlines how the close cooperation between surgeons and radiologists results in a quick diagnosis and management of such pathological events.

10.
Eur J Histochem ; 60(4): 2642, 2016 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-28076936

RESUMO

Bone graft are used in dentistry for the reconstruction of severely atrophic jaws. Fresh frozen bone has no osteogenic property but it has osteoconductive and osteoinductive properties because its matrix contains growth factors such as vascular endothelial growth factor. The purpose of the present study was to evaluate morphological and protein expression characteristics of fresh frozen bone before graft and after six months of graft in patients who needed maxillary reconstruction. After 6 month of graft we observed the presence of viable bone as evidenced by full osteocyte lacunae and by the presence of RANKR, osteocalcin positive cells and vascular endothelial growth factor. In conclusion, our findings show that the fresh frozen bone after six month of graft is for the most part viable bone, encouraging its use as an alternative to autogenous bone for reconstructing maxillary bone defects prior to implant.


Assuntos
Transplante Ósseo , Criopreservação , Maxila/citologia , Maxila/metabolismo , Feminino , Humanos , Masculino
11.
Phys Med ; 30(1): 96-103, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23623589

RESUMO

BACKGROUND AND PURPOSE: The Medical Physics Division of the Portuguese Physics Society (DFM_SPF) in collaboration with the IAEA, carried out a national auditing project in radiotherapy, between September 2011 and April 2012. The objective of this audit was to ensure the optimal usage of treatment planning systems. The national results are presented in this paper. MATERIAL AND METHODS: The audit methodology simulated all steps of external beam radiotherapy workflow, from image acquisition to treatment planning and dose delivery. A thorax CIRS phantom lend by IAEA was used in 8 planning test-cases for photon beams corresponding to 15 measuring points (33 point dose results, including individual fields in multi-field test cases and 5 sum results) in different phantom materials covering a set of typical clinical delivery techniques in 3D Conformal Radiotherapy. RESULTS: All 24 radiotherapy centers in Portugal have participated. 50 photon beams with energies 4-18 MV have been audited using 25 linear accelerators and 32 calculation algorithms. In general a very good consistency was observed for the same type of algorithm in all centres and for each beam quality. CONCLUSIONS: The overall results confirmed that the national status of TPS calculations and dose delivery for 3D conformal radiotherapy is generally acceptable with no major causes for concern. This project contributed to the strengthening of the cooperation between the centres and professionals, paving the way to further national collaborations.


Assuntos
Auditoria Clínica , Radiometria/normas , Planejamento da Radioterapia Assistida por Computador/normas , Imagens de Fantasmas , Portugal , Dosagem Radioterapêutica
12.
Int J Nanomedicine ; 8: 3883-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24143092

RESUMO

BACKGROUND: To date, there are no studies reported in the literature on the possible use of bovine collagen, oxidized regenerated cellulose, or synthetic hyaluronic acid medications in the oral cavity. The aim of this paper is to report the use of bovine collagen, oxidized regenerated cellulose, and synthetic hyaluronic acid medications to improve wound healing in the oral cavity by stimulating granulomatous tissue. METHODS: From 2007 to 2011, 80 patients (median age 67 years) suffering from oral mucosal lesions participated in this double-blind study. The patients were divided into two groups, each consisting of 40 patients. One group received conventional medications, while the other group of patients were treated with the advanced medications. RESULTS: Advanced medications allowed re-epithelialization of the wound margin in 2-20 days, whereas patients receiving conventional medication showed a median healing duration of 45 days. CONCLUSION: The results of this study demonstrate that treating oral mucosal wounds with advanced medication has an advantage with regard to wound healing time, allowing patients to have a rapid, functional, and esthetic recovery.


Assuntos
Bandagens , Celulose Oxidada/uso terapêutico , Ácido Hialurônico/uso terapêutico , Boca/efeitos dos fármacos , Boca/lesões , Lesões dos Tecidos Moles/patologia , Lesões dos Tecidos Moles/terapia , Idoso , Feminino , Humanos , Masculino , Resultado do Tratamento , Cicatrização/efeitos dos fármacos
13.
Eur Rev Med Pharmacol Sci ; 16 Suppl 4: 125-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23090828

RESUMO

The odontoameloblastoma (OA), also known as ameloblastic odontoma, is a rare neoplasm of jaws which includes odontogenic ectomesenchyme in addition to odontogenic epithelium that resembles an ameloblastoma both in structure and in behaviour. The exact incidence is difficult to determine. Since 1944, only 24 cases have been reported in English literature which fulfill both histological and clinical features of this lesion. The Authors report a case report of an odontoameloblastoma in a 15-year-old caucasian man treated with a surgical excision. The five years follow-up shows no evidence of recurrence confirming the validity of a conservative surgery with enucleation of OA, followed by periodical clinical and radiographical controls.


Assuntos
Ameloblastoma/cirurgia , Neoplasias Maxilomandibulares/cirurgia , Adolescente , Ameloblastoma/diagnóstico , Ameloblastoma/patologia , Seguimentos , Humanos , Neoplasias Maxilomandibulares/diagnóstico , Neoplasias Maxilomandibulares/patologia , Masculino
14.
Appl Radiat Isot ; 66(1): 44-9, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17855102

RESUMO

A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.


Assuntos
Câmaras gama/estatística & dados numéricos , Cintilografia/estatística & dados numéricos , Humanos , Imagens de Fantasmas , Radiobiologia , Sensibilidade e Especificidade
15.
Hematol Oncol ; 25(4): 164-9, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17577204

RESUMO

Osteonecrosis of the jaws (ONJ) associated with the use of bisphosphonates is a newly described entity. To elucidate the mechanism leading to ONJ and to test the hypothesis that in patients with ONJ the bisphosphonates may interfere with endothelial cell proliferation, using flow cytometric analysis we evaluated the number of circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) in eight patients with bisphosphonate treatment and osteonecrosis, eight multiple myeloma (MM) patients with bisphosphonates treatment without ONJ and five normal subjects. MM patients showed an increase of CD34+ cells with respect the control subjects and ONJ subjects. EPCs and CECs were higher in MM patients compared to controls and ONJ patients. ONJ patients showed a decrease of EPCs compared to control subjects while CECs were similar to the controls group. Our results seem to show the possibility that bisphosphonates could have a antiangiogenic effect and a suppressive effect on CECs of patients with ONJ.


Assuntos
Difosfonatos/efeitos adversos , Células Endoteliais/patologia , Doenças Maxilomandibulares/induzido quimicamente , Osteonecrose/induzido quimicamente , Idoso , Idoso de 80 Anos ou mais , Inibidores da Angiogênese , Sangue , Estudos de Casos e Controles , Contagem de Células , Feminino , Citometria de Fluxo , Humanos , Masculino , Pessoa de Meia-Idade , Células-Tronco/patologia
16.
Acta Haematol ; 117(3): 181-7, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17164581

RESUMO

Osteonecrosis of the jaw is an unremitting adverse outcome associated with bisphosphonate therapy in patients with multiple myeloma or bone metastases from solid tumors. Twelve patients who presented with exposed bone associated with bisphosphonates were reviewed to determine the type, dosage and duration of their bisphosphonate therapy, presenting findings, comorbidities and the event that incited the bone exposure. The discontinuation of bisphosphonate therapy has not helped reverse the presence of osteonecrosis, and the surgical manipulation of the involved site appears to worsen the underlying bone pathology. Hyperbaric oxygen, which has proven efficacious in other forms of osteonecrosis by establishing an oxygen gradient, is of no definitive benefit to patients with bisphosphonate-induced exposed bone. Antibiotic therapy is useful in controlling pain and swelling but ineffective in preventing the progression of the exposed bone. To date, prevention is the only currently possible therapeutic approach to the management of this complication.


Assuntos
Conservadores da Densidade Óssea/efeitos adversos , Neoplasias da Mama/complicações , Difosfonatos/efeitos adversos , Imidazóis/efeitos adversos , Mieloma Múltiplo/complicações , Osteonecrose/induzido quimicamente , Osteonecrose/etiologia , Alendronato/efeitos adversos , Neoplasias Ósseas/secundário , Neoplasias da Mama/patologia , Feminino , Humanos , Doenças Maxilomandibulares/induzido quimicamente , Doenças Maxilomandibulares/etiologia , Doenças Maxilomandibulares/patologia , Masculino , Mandíbula/diagnóstico por imagem , Mandíbula/patologia , Maxila/diagnóstico por imagem , Maxila/patologia , Pessoa de Meia-Idade , Necrose , Osteonecrose/patologia , Pamidronato , Tomografia Computadorizada por Raios X , Ácido Zoledrônico
17.
Interv Neuroradiol ; 13(4): 385-8, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20566108

RESUMO

SUMMARY: We describe a rare case of mandibular highflow arteriovenous malformation (AVM) mimicking an odontogenic cyst in a young man. The diagnosis of mandibular AVM was made by CT angiography and confirmed by digital subtraction angiography. CT scan showed the extent of mandibular bone alteration and a double enlarged mandibular canal on the same side. An AVM containing a large aneurysm was demonstrated by CT angiography.The mandibular AVM was successfully treated by endovascular therapy with Guglielmi detachable coils. On panoramic radiogram, mandibular AVMs can appear as cystic lesions without pathognomonic features. Several benign and malignant tumours of this anatomical region must be considered in the differential diagnosis.We emphasize the radiological sign of double enlarged mandibular canal and the diagnostic role of CT, particularly CT angiography, to discriminate a mandibular AVM from neoplastic entities of this region, sparing the risks of a needle biopsy.

18.
Radiat Prot Dosimetry ; 122(1-4): 509-12, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17166873

RESUMO

In this work, a set of 50 alanine dosimeters has been used in a radiotherapy context, simulating a two-dimensional treatment in a non-overlapping dosimeter configuration. The dose is reconstructed from physical and numerical simulation of the electron paramagnetic resonance signal, calculating the spin density. Thus, it can be used to better adjust the error in the calibration curve to give a final accuracy of <0.03 Gy. A complete set of experimental test parameters have been used with a standard dosimeter in order to obtain the best analysis configuration. These results indicate that for a conventional treatment of some hundreds of mGy, this method can be useful with a correct signal validation. A numerical test and fitting software has been developed. The general use of alanine/electron paramagnetic resonance dosimetry in radiotherapy context is discussed.


Assuntos
Alanina/química , Alanina/efeitos da radiação , Espectroscopia de Ressonância de Spin Eletrônica/instrumentação , Modelos Químicos , Radiometria/instrumentação , Radiometria/métodos , Planejamento da Radioterapia Assistida por Computador/instrumentação , Simulação por Computador , Desenho Assistido por Computador , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Eur J Ophthalmol ; 12(5): 419-23, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12474926

RESUMO

PURPOSE: To seek out correlations between preoperative electro-oculogram (EOG) recordings with different types of uveal melanomas, after surgery. METHODS: We analysed the EOG recordings of 120 patients with uveal melanomas, histologically verified, 100 in the choroid and 20 in the iris and ciliary body. The EOG data were correlated with the site, size and histological type of the tumor. RESULTS: In 100 eyes with choroidal melanoma the Arden Index (AI) was less than in fellow eyes (mean 126.6, SD +/- 23.8 and 202.9, SD +/- 47.0; p=0.01). The EOG values were not different with respect to the histological type, site and size of tumor. In cases with iris and ciliary body melanomas the AI were not significantly different from the fellow eyes (mean 180.6, SD +/- 23.6 and 203.2, SD +/- 38.7; p=0.07). CONCLUSIONS: Since the EOG is abnormal in eyes with choroidal melanoma, it can be considered a powerful auxiliary for diagnosing these tumors.


Assuntos
Eletroculografia , Melanoma/diagnóstico , Neoplasias Uveais/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Coroide/diagnóstico , Corpo Ciliar , Humanos , Neoplasias da Íris/diagnóstico , Pessoa de Meia-Idade
20.
J Clin Invest ; 106(9): 1095-103, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11067862

RESUMO

Growth hormone (GH) regulates both bone growth and remodeling, but it is unclear whether these actions are mediated directly by the GH receptor (GHR) and/or IGF-I signaling. The actions of GH are transduced by the Jak/Stat signaling pathway via Stat5, which is thought to regulate IGF-I expression. To determine the respective roles of GHR and IGF-I in bone growth and remodeling, we examined bones of wild-type, GHR knockout (GHR(-/-)), Stat5ab(-/-), and GHR(-/-) mice treated with IGF-I. Reduced bone growth in GHR(-/-) mice, due to a premature reduction in chondrocyte proliferation and cortical bone growth, was detected after 2 weeks of age. Additionally, although trabecular bone volume was unchanged, bone turnover was significantly reduced in GHR(-/-) mice, indicating GH involvement in the high bone-turnover level during growth. IGF-I treatment almost completely rescued all effects of the GHR(-/-) on both bone growth and remodeling, supporting a direct effect of IGF-I on both osteoblasts and chondrocytes. Whereas bone length was reduced in Stat5ab(-/-) mice, there was no reduction in trabecular bone remodeling or growth-plate width as observed in GHR(-/-) mice, indicating that the effects of GH in bone may not involve Stat5 activation.


Assuntos
Desenvolvimento Ósseo/fisiologia , Remodelação Óssea/fisiologia , Hormônio do Crescimento/deficiência , Fator de Crescimento Insulin-Like I/farmacologia , Proteínas do Leite , Animais , Desenvolvimento Ósseo/efeitos dos fármacos , Desenvolvimento Ósseo/genética , Remodelação Óssea/efeitos dos fármacos , Remodelação Óssea/genética , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Hormônio do Crescimento/genética , Hormônio do Crescimento/fisiologia , Homeostase , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Proteínas Recombinantes/farmacologia , Fator de Transcrição STAT5 , Transativadores/deficiência , Transativadores/genética , Transativadores/fisiologia
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