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1.
J Cancer Res Clin Oncol ; 149(9): 5665-5676, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36538146

RESUMO

PURPOSE: In recent years, therapeutic strategies based on tumour biology have increased significantly. We aimed to provide an overview of the recent changes in patient characteristics, treatment procedures and survival factors for two groups of patients: women younger than 35 years and women between 50 and 69 years. METHODS: We used data from the population-based Cancer Registry Magdeburg. Subjects included women with non-metastatic breast cancer treated between 2000 and 2015. We compared between two observation periods: 2000-2007 and 2008-2015. RESULTS: There was an increase in patient survival from the first to the second observation period. Tumour characteristics and treatment modalities changed, especially in the group of older patients. The proportion of prognostically more favourable tumour subtypes, such as Luminal A, increased significantly. Between 2008 and 2015, there were more hormone receptor-positive, lymph-node-negative, human epidermal growth factor receptor-2 (HER2)-negative and well-differentiated tumours. Surgical methods were associated with significantly reduced radicality, while the rate of neoadjuvant therapy increased in both groups. There was a decrease in cyclophosphamide, methotrexate and 5-fluoruracil (CMF) and anthracycline therapies, but taxane-containing chemotherapy increased. While tamoxifen was used more frequently in younger patients in the later observation period, its use was reduced in older patients, superseded by aromatase inhibitors. Furthermore, the use of immune therapy increased. CONCLUSION: In both age groups, but primarily in older patients, there were significant changes in tumour biology and treatment options between the two observation periods. These changes have led to a continuous improvement in patient outcomes.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Idoso , Neoplasias da Mama/patologia , Tamoxifeno/uso terapêutico , Ciclofosfamida/uso terapêutico , Metotrexato/uso terapêutico , Fluoruracila/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimioterapia Adjuvante
2.
Prev Med Rep ; 23: 101452, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34221852

RESUMO

We aimed to identify how additional information about benefits and harms of cervical cancer (CC) screening impacted intention to participate in screening, what type of information on harms women preferred receiving, from whom, and whether it differed between two national healthcare settings. We conducted a survey that randomized screen-eligible women in the United States (n = 1084) and Norway (n = 1060) into four groups according to the timing of introducing additional information. We found that additional information did not significantly impact stated intentions-to-participate in screening or follow-up testing in either country; however, the proportion of Norwegian women stating uncertainty about seeking precancer treatment increased from 7.9% to 14.3% (p = 0.012). Women reported strong system-specific preferences for sources of information: Norwegians (59%) preferred it come from a national public health agency while Americans (59%) preferred it come from a specialist care provider. Regression models revealed having a prior Pap-test was the most important predictor of intentions-to-participate in both countries, while having lower income reduced the probabilities of intentions-to-follow-up and seek precancer treatment among U.S. women. These results suggest that additional information on harms is unlikely to reduce participation in CC screening but could increase decision uncertainty to seek treatment. Providing unbiased information would improve on the ethical principle of respect for autonomy and self-determination. However, the clinical impact of additional information on women's understanding of the trade-offs involved with CC screening should be investigated. Future studies should also consider country-specific socioeconomic barriers to screening if communication re-design initiatives aim to improve CC screening participation.

3.
Foot Ankle Surg ; 23(4): e9-e13, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29203003

RESUMO

BACKGROUND: Mirror foot is a rare anomaly and limited long term follow-up information is available. METHODS: Seven years after operation a mirror foot patient returned with foot complaints and was evaluated using radiographs and clinical examination. A systematic literature search was conducted to study foot complaints in mirror feet. RESULTS: Different origins of foot pain were considered in our patient; tibia length difference, deformed talus and accessory osseous structures in the tarsal region. Literature search resulted in 118 mirror feet. Based on cases reporting osseous structures, 74.2% showed tibia abnormalities and 94.5% an abnormal tarsal region. Only three cases mentioned a normal talus. Nine cases reported a follow-up period of more than five years. CONCLUSION: Osseous abnormalities are not always visible at birth, but are often present. Therefore, detailed examination of the affected limb in mirror foot patients with foot pain is important, in order to localize the origin.


Assuntos
Deformidades Congênitas do Pé/complicações , Deformidades Congênitas do Pé/cirurgia , Dor Musculoesquelética/etiologia , Criança , Seguimentos , Deformidades Congênitas do Pé/diagnóstico por imagem , Humanos , Masculino , Procedimentos de Cirurgia Plástica
4.
BJOG ; 124(3): 474-484, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27264207

RESUMO

OBJECTIVE: To evaluate the short-term consequences and cost-effectiveness associated with the use of novel biomarkers to triage young adult women with minor cervical cytological lesions. DESIGN: Model-based economic evaluation using primary epidemiological data from Norway, supplemented with data from European and American clinical trials. SETTING: Organised cervical cancer screening in Norway. POPULATION: Women aged 25-33 years with minor cervical cytological lesions detected at their primary screening test. METHODS: We expanded an existing simulation model to compare 12 triage strategies involving alternative biomarkers (i.e. reflex human papillomavirus (HPV) DNA/mRNA testing, genotyping, and dual staining) with the current Norwegian triage guidelines. MAIN OUTCOME MEASURES: The number of high-grade precancers detected and resource use (e.g. monetary costs and colposcopy referrals) for a single screening round (3 years) for each triage strategy. Cost-efficiency, defined as the additional cost per additional precancer detected of each strategy compared with the next most costly strategy. RESULTS: Five strategies were identified as cost-efficient, and are projected to increase the precancer detection rate between 18 and 57%, compared with current guidelines; however, the strategies did not uniformly require additional resources. Strategies involving HPV mRNA testing required fewer resources, whereas HPV DNA-based strategies detected >50% more precancers, but were more costly and required twice as many colposcopy referrals compared with the current guidelines. CONCLUSION: Strategies involving biomarkers to triage younger women with minor cervical cytological lesions have the potential to detect additional precancers, yet the optimal strategy depends on the resources available as well as decision-makers' and women's acceptance of additional screening procedures. TWEETABLE ABSTRACT: Women with minor cervical lesions may be triaged more accurately and effectively using novel biomarkers.


Assuntos
Biomarcadores/análise , Detecção Precoce de Câncer/economia , Triagem/economia , Doenças do Colo do Útero/diagnóstico , Adulto , Colo do Útero/patologia , Análise Custo-Benefício , Detecção Precoce de Câncer/métodos , Feminino , Testes de DNA para Papilomavírus Humano , Humanos , Noruega , Triagem/estatística & dados numéricos , Doenças do Colo do Útero/economia , Esfregaço Vaginal , Adulto Jovem
5.
J Cancer Res Clin Oncol ; 142(5): 1109-16, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26809246

RESUMO

INTRODUCTION: Elderly breast cancer patients aged ≥75 years are underrepresented in most studies. Therefore, data on cancer characteristics, adjuvant treatment and survival in elderly patients are missing. PATIENTS AND METHODS: In this retrospective study, we compared tumor characteristics and adjuvant therapy in 973 women with invasive, non-metastasized breast cancer aged ≥75 years with 3377 younger postmenopausal patients (50-74 years old). Time dynamics of tumor characteristics were investigated, comparing two observation periods between the years 2000-2004 versus 2005-2008. RESULTS: Compared to younger women, older patients were more often treated with mastectomy and less likely to receive adjuvant treatment. Although the overall survival rate increased over the observation period in both age groups, the older study group was characterized by shorter disease-free survival. Additionally, we observed an increase in about 1.65 years in the age at diagnosis as well as an increasing rate of breast-conserving surgery and sentinel lymph node biopsy for the whole study population between 2000 and 2008. Furthermore, we found a reduction in the proportion of estrogen receptor-positive tumors in the younger women and a decrease in G3-tumors in both age groups over the study time. CONCLUSION: The older group's reduced disease-free survival could be explained by the tumor characteristics and differences in the adjuvant treatment. Remarkably, elderly women are more likely to be overtreated surgically while being undertreated in terms of adjuvant therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Lobular/patologia , Idoso , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Neoplasias da Mama/terapia , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/mortalidade , Carcinoma Ductal de Mama/terapia , Carcinoma Lobular/metabolismo , Carcinoma Lobular/mortalidade , Carcinoma Lobular/terapia , Quimioterapia Adjuvante , Terapia Combinada , Feminino , Seguimentos , Humanos , Técnicas Imunoenzimáticas , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estadiamento de Neoplasias , Prognóstico , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Estudos Retrospectivos , Biópsia de Linfonodo Sentinela , Taxa de Sobrevida
7.
Dtsch Med Wochenschr ; 140(11): e106-13, 2015 May.
Artigo em Alemão | MEDLINE | ID: mdl-26080728

RESUMO

BACKGROUND AND AIM: In Germany, data of cancer patients are recorded not only in epidemiological registers but also in clinical cancer registers. To ensure the networking of all included medical partners, quality control, and clinical research it is necessary that cancer cases are captured more or less completely. The aim of the present study was to compare the data sets of two registers. PATIENTS AND METHODS: Data from patients with colorectal cancer from two large surgical clinics in Magdeburg are recorded in two registers - the Clinical Cancer Registry Magdeburg and the Institute of Quality Assurance in Operative Medicine at the Otto-von-Guericke University Magdeburg. Here we compared the data sets in order to check the completeness of data capturing and to determine factors influencing the degree of completeness. RESULTS: From all patients captured in the Institute of Quality Assurance, 78.9% are found also in the clinical cancer registry. The percentage improves over the course of time, but also depends on diagnostic criteria such as the staging. There are some differences between both registries, explainable by their specific objectives. Particularly, it is demonstrated that incomplete follow-up record may bias estimates of survival rates from registries. CONCLUSION: Ensuring the completeness and correctness of data is a major challenge for cancer registries. It has distinct influence on estimated quality parameters such as survival rates.


Assuntos
Neoplasias Colorretais/epidemiologia , Sistema de Registros/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Viés , Carcinoma in Situ/diagnóstico , Carcinoma in Situ/epidemiologia , Carcinoma in Situ/terapia , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/terapia , Feminino , Seguimentos , Tumores do Estroma Gastrointestinal/diagnóstico , Tumores do Estroma Gastrointestinal/epidemiologia , Tumores do Estroma Gastrointestinal/terapia , Alemanha/epidemiologia , Humanos , Linfoma/diagnóstico , Linfoma/epidemiologia , Linfoma/terapia , Masculino , Melanoma/diagnóstico , Melanoma/epidemiologia , Melanoma/terapia , Pessoa de Meia-Idade , Tumores Neuroendócrinos/diagnóstico , Tumores Neuroendócrinos/epidemiologia , Tumores Neuroendócrinos/terapia , Fechamento Perceptivo , Projetos de Pesquisa/normas , Sarcoma/diagnóstico , Sarcoma/epidemiologia , Sarcoma/terapia , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/terapia , Taxa de Sobrevida
8.
S Afr Med J ; 105(1): 27-30, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26046158

RESUMO

Despite improvements to the Death Notification Form (DNF) used in South Africa (SA), the quality of cause-of-death information remains suboptimal. To address these inadequacies, the government ran a train-the-trainer programme on completion of the DNF, targeting doctors in public sector hospitals. Training materials were developed and workshops were held in all provinces. This article reflects on the lessons learnt from the training and highlights issues that need to be addressed to improve medical certification and cause-of-death data in SA. The DNF should be completed truthfully and accurately, and confidentiality of the information on the form should be maintained. The underlying cause of death should be entered on the lowest completed line in the cause-of-death section, and if appropriate, HIV should be entered here. Exclusion clauses for HIV in life insurance policies with Association of Savings and Investments South Africa companies were scrapped in 2005. Interactive workshops provide a good learning environment, but are logistically challenging. More use should be made of online training resources, particularly with continuing professional development accreditation and helpline support. In addition, training in the completion of the DNF should become part of the curriculum in all medical schools, and part of the orientation of interns and community service doctors in all facilities.


Assuntos
Causas de Morte , Currículo , Atestado de Óbito , Educação Médica/métodos , Médicos/organização & administração , Educação Médica/tendências , Humanos , Médicos/tendências , Faculdades de Medicina , África do Sul
9.
Crit Rev Oncol Hematol ; 94(2): 164-78, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25620327

RESUMO

PURPOSE: The purpose of this study was to provide a clinician-friendly overview of decision-analytic models evaluating different treatment strategies for multiple myeloma (MM). METHODS: We performed a systematic literature search to identify studies evaluating MM treatment strategies using mathematical decision-analytic models. We included studies that were published as full-text articles in English, and assessed relevant clinical endpoints, and summarized methodological characteristics (e.g., modeling approaches, simulation techniques, health outcomes, perspectives). RESULTS: Eleven decision-analytic modeling studies met our inclusion criteria. Five different modeling approaches were adopted: decision-tree modeling, Markov state-transition modeling, discrete event simulation, partitioned-survival analysis and area-under-the-curve modeling. Health outcomes included survival, number-needed-to-treat, life expectancy, and quality-adjusted life years. Evaluated treatment strategies included novel agent-based combination therapies, stem cell transplantation and supportive measures. CONCLUSION: Overall, our review provides a comprehensive summary of modeling studies assessing treatment of MM and highlights decision-analytic modeling as an important tool for health policy decision making.


Assuntos
Tomada de Decisões , Técnicas de Apoio para a Decisão , Simulação por Computador , Análise Custo-Benefício , Gerenciamento Clínico , Humanos , Modelos Estatísticos , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/mortalidade , Mieloma Múltiplo/terapia , Análise de Sobrevida
11.
Environ Sci Technol ; 47(2): 750-6, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23237387

RESUMO

Silicate glasses are used as containment matrices for deep geological disposal of nuclear waste arising from spent fuel reprocessing. Understanding the dissolution mechanisms of glasses in contact with iron, an element present in large amounts in the immediate environment (overpack, claystone, etc.) would be a major breakthrough toward predicting radionuclide release in the geosphere after disposal. Two different reacted glass-iron interfaces-a short-term nuclear system and a long-term archeological system-were examined using a multiscale and multianalytical approach including, for the first time on samples of this type, STXM under synchrotron radiation. Comparisons revealed remarkable similarities between the two systems and shed light on Fe-Si interactions, including migration of iron within a porous gel layer and precipitation of Fe-silicates that locally increase short-term glass alteration and are sustainable over the long-term.


Assuntos
Vidro/química , Ferro/química , Silicatos/química , Porosidade , Resíduos Radioativos/análise , Solubilidade
12.
Br J Cancer ; 106(9): 1571-8, 2012 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-22441643

RESUMO

BACKGROUND: New screening technologies and vaccination against human papillomavirus (HPV), the necessary cause of cervical cancer, may impact optimal approaches to prevent cervical cancer. We evaluated the cost-effectiveness of alternative screening strategies to inform cervical cancer prevention guidelines in Norway. METHODS: We leveraged the primary epidemiologic and economic data from Norway to contextualise a simulation model of HPV-induced cervical cancer. The current cytology-only screening was compared with strategies involving cytology at younger ages and primary HPV-based screening at older ages (31/34+ years), an option being actively deliberated by the Norwegian government. We varied the switch-age, screening interval, and triage strategies for women with HPV-positive results. Uncertainty was evaluated in sensitivity analysis. RESULTS: Current cytology-only screening was less effective and more costly than strategies that involve switching to primary HPV testing in older ages. For unvaccinated women, switching at age 34 years to primary HPV testing every 4 years was optimal given the Norwegian cost-effectiveness threshold ($83,000 per year of life saved). For vaccinated women, a 6-year screening interval was cost-effective. When we considered a wider range of strategies, we found that an earlier switch to HPV testing (at age 31 years) may be preferred. CONCLUSIONS: Strategies involving a switch to HPV testing for primary screening in older women is expected to be cost-effective compared with current recommendations in Norway.


Assuntos
Detecção Precoce de Câncer/economia , Infecções por Papillomavirus/economia , Infecções por Papillomavirus/prevenção & controle , Neoplasias do Colo do Útero/economia , Neoplasias do Colo do Útero/prevenção & controle , Adulto , Análise Custo-Benefício , DNA Viral/genética , Feminino , Humanos , Modelos Teóricos , Noruega , Papillomaviridae/genética , Infecções por Papillomavirus/diagnóstico , Reação em Cadeia da Polimerase , Prognóstico , Anos de Vida Ajustados por Qualidade de Vida , Neoplasias do Colo do Útero/diagnóstico , Esfregaço Vaginal
13.
Gynecol Oncol ; 120(3): 430-8, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21130490

RESUMO

OBJECTIVE: Perform a systematic review to determine the test performance of HPV mRNA testing compared to DNA testing using CIN2+ as the target condition. METHODS: We searched bibliographic databases (MEDLINE, EMBASE and Cochrane Library) from January 1996 through August 2010 using a predefined search strategy. The reference standard used to diagnose precancerous lesions was histologically confirmed cervical intraepithelial neoplasia 2+ (CIN2+). Two reviewers independently assessed study eligibility, extracted data, and assessed risk of bias. Sensitivity, specificity, positive and negative likelihood ratios and diagnostic odds ratios were calculated for each study. In addition, we fitted a series of summary receiver operating characteristics (SROC) curves. A subgroup analysis was performed according to specific inclusion covariates. RESULTS: Out of 3179 potentially relevant citations, 12 publications (11 studies) met our inclusion criteria. The included studies were of varying methodological quality, and were predominately performed in a secondary screening setting. Eight studies investigated the performance of the PreTect Proofer/NucliSENS EasyQ, two studies investigated the performance of the APTIMA assay and one study investigated both mRNA tests on the same patient samples. Due to few studies and considerable clinical heterogeneity, pooling of data was not possible. Instead, we compiled a 'best evidence synthesis' for E6/E7 mRNA HPV testing. Sensitivities ranged from 0.41 to 0.86 and from 0.90 to 0.95 for the PreTect Proofer/Easy Q and APTIMA assay, respectively. Specificities ranged from 0.63 to 0.97 and from 0.42 to 0.61 for the PreTect Proofer/Easy Q and APTIMA assay, respectively. The SROC curves for both mRNA tests were to the left of the diagonal and the APTIMA assay performed closest to the DNA tests. CONCLUSION: The review suggests that mRNA tests have diagnostic relevance, but additional studies and economic evaluations must be conducted in order to make a solid conclusion regarding the clinical applicability of HPV mRNA testing.


Assuntos
Papillomaviridae/isolamento & purificação , RNA Mensageiro/análise , RNA Viral/análise , Displasia do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/diagnóstico , Feminino , Humanos , Papillomaviridae/genética , Curva ROC , Sensibilidade e Especificidade , Neoplasias do Colo do Útero/virologia , Displasia do Colo do Útero/virologia
15.
Stud Mycol ; 58: 219-34, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18491001

RESUMO

Cladophialophora carrionii is one of the four major etiologic agents of human chromoblastomycosis in semi-arid climates. This species was studied using sequence data of the internal transcribed spacer region of rDNA, the partial beta-tubulin gene and an intron in the translation elongation factor 1-alpha gene, in addition to morphology. With all genes a clear bipartition was observed, which corresponded with minute differences in conidiophore morphology. A new species, C. yegresii, was introduced, which appeared to be, in contrast to C. carrionii, associated with living cactus plants. All strains from humans, and a few isolates from dead cactus debris, belonged to C. carrionii, for which a lectotype was designated. Artificial inoculation of cactus plants grown from seeds in the greenhouse showed that both fungi are able to persist in cactus tissue. When reaching the spines they produce cells that morphologically resemble the muriform cells known as the "invasive form" in chromoblastomycosis. The tested clinical strain of C. carrionii proved to be more virulent in cactus than the environmental strain of C. yegresii that originated from the same species of cactus, Stenocereus griseus. The muriform cell expressed in cactus spines can be regarded as the extremotolerant survival phase, and is likely to play an essential role in the natural life cycle of these organisms.

16.
Calcif Tissue Int ; 79(6): 404-15, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17160577

RESUMO

Mechanical loading and estrogen play important roles in bone homeostasis. The aim of this study was to evaluate the effects of mechanical loading on trabecular bone in the proximal femur of ovariectomized rats. We hypothesized that mechanical loading suppresses bone resorption and increases bone formation, which differs from the suppressive effects of estrogen on both resorption and formation. Furthermore, we expected to find changes in trabecular architecture elicited by the effects of mechanical loading and estrogen deficiency. Sixty female Wistar rats, 12 weeks old, were assigned to either the sedentary groups sham surgery (SED), ovariectomy (SED+OVX), and ovariectomy with estrogen replacement (SED+OVX+E2) or to the exercise groups EX, EX+OVX, EX+OVX+E2. Following ovariectomy, 5 microg 17beta-estradiol was given once weekly to the estrogen replacement groups. Exercise consisted of running with a backpack (load +/-20% of body weight) for 15 minutes/day, 5 days/week, for 19 weeks. Dual-energy X-ray absorptiometry (DXA) scans were performed before (T0), during (T6), and after (T19) the exercise period to obtain bone mineral content (BMC) and bone mineral density (BMD) data. After the exercise program, all rats were killed and right and left femora were dissected and prepared for micro-CT scanning and histomorphometric analysis of the proximal femoral metaphysis. After 19 weeks, increases in BMC (P = 0.010) and BMD (P = 0.031) were significant. At T19, mechanical loading had a significant effect on BMC (P = 0.025) and BMD (P = 0.010), and an interaction between mechanical loading and estrogen (P = 0.023) was observed. Bone volume and trabecular number decreased significantly after ovariectomy, while trabecular separation, mineralizing surface, bone formation rate, osteoclast surface, degree of anisotropy, and structure model index increased significantly after ovariectomy (P < 0.05). Trabecular bone turnover and structural parameters in the proximal femur were not affected by exercise. Estrogen deficiency resulted in a less dense and more oriented trabecular bone structure with increased marrow cavity and a decreased number of trabeculae. In conclusion, mechanical loading has beneficial effects on BMC and BMD of the ovariectomized rat. This indicates that the load in the backpack was high enough to elicit an osteogenic response sufficient to compensate for the ovariectomy-induced bone loss. The results confirm that estrogen suppresses both bone resorption and bone formation in the proximal metaphysis in the femoral head of our rat-with-backpack model. The effects of mechanical loading on the trabecular bone of the femoral head were not significant. This study suggests that the effect of mechanical loading in the rat-with-backpack model mainly occurs at cortical bone sites.


Assuntos
Densidade Óssea , Remodelação Óssea/fisiologia , Fêmur/metabolismo , Osteogênese/fisiologia , Condicionamento Físico Animal , Suporte de Carga/fisiologia , Absorciometria de Fóton , Animais , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Remodelação Óssea/efeitos dos fármacos , Estradiol/farmacologia , Terapia de Reposição de Estrogênios , Feminino , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Ovariectomia , Ratos , Ratos Wistar , Estresse Mecânico
17.
Osteoporos Int ; 17(6): 827-33, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16565787

RESUMO

INTRODUCTION: Osteoporosis (OP) and osteoarthritis (OA) are both common diseases in the elderly, but remarkably seldom coexist. The bone defects that are related to both diseases develop with increasing age, which suggests that they are related to some form of imperfect bone remodeling. Current opinion holds that the bone remodeling process is supervised by bone cells that respond to mechanical stimuli. An imperfect response of bone cells to mechanical stimuli might thus relate to imperfect bone remodeling, which could eventually lead to a lack bone mass and strength, such as in OP patients. MATERIALS: To investigate whether the cellular response to mechanical stress differs between OP and OA patients, we compared the response of bone cells from both groups to fluid shear stress of increasing magnitude. Bone cells from 9 female OP donors (age 60-90 year) and 9 female age-matched OA donors were subjected to pulsating fluid flow (PFF) of low (0.4+/-0.1 Pa at 3 Hz), medium (0.6+/-0.3 Pa at 5 Hz), or high shear stress (1.2+/-0.4 at 9Hz), or were kept under static culture conditions. RESULTS: We found subtle differences in the shear-stress response of the two groups, measured as nitric oxide (NO) and prostaglandin E2 (PGE2) production. The NO-response to shear stress was higher in the OP than the OA cells, while the PGE2-response was higher in the OA cells. CONCLUSIONS: Assuming that NO and PGE2 play a role in cell-cell communication during remodeling, these results suggest that slight differences in mechanotransduction might relate to the opposite bone defects in osteoporosis and osteoarthritis.


Assuntos
Osso e Ossos/metabolismo , Dinoprostona/biossíntese , Óxido Nítrico/biossíntese , Osteoartrite/metabolismo , Osteoblastos/metabolismo , Osteoporose/metabolismo , Estresse Mecânico , Idoso , Idoso de 80 Anos ou mais , Osso e Ossos/citologia , Feminino , Humanos , Pessoa de Meia-Idade , Fluxo Pulsátil
18.
J Anat ; 208(1): 73-9, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16420380

RESUMO

Longitudinal growth of long bones takes place at the growth plates. The growth plate produces new bone trabeculae, which are later resorbed or merged into the cortical shell. This process implies transition of trabecular metaphyseal sections into diaphyseal sections. We hypothesize that the development of cortical bone is governed by mechanical stimuli. We also hypothesize that trabecular and cortical bone share the same regulatory mechanisms for adaptation to mechanical loads. To test these hypotheses, we monitored the development of the tibial cortex in growing pigs, using micro-computer tomography and histology. We then tested the concept that regulatory mechanisms for trabecular bone adaptation can also explain cortical bone development using our mechanical stimulation theory, which could explain trabecular bone (re)modelling. The main results showed that, from the growth plate towards the diaphysis, the pores of the trabecular structure were gradually filled in with bone, which resulted in increased density and cortical bone. The computer model largely predicted this morphological development. We conclude that merging of metaphyseal trabeculae into cortex is likely to be governed by mechanical stimuli. Furthermore, cortex development of growing long bones can be explained as a form of trabecular bone adaptation, without the need for different regulatory mechanisms for cortical and trabecular bone.


Assuntos
Desenvolvimento Ósseo/fisiologia , Lâmina de Crescimento/fisiologia , Adaptação Fisiológica , Animais , Fenômenos Biomecânicos , Remodelação Óssea/fisiologia , Simulação por Computador , Análise de Elementos Finitos , Modelos Biológicos , Estresse Mecânico , Suínos , Tíbia/crescimento & desenvolvimento , Tomografia/métodos
19.
Osteoporos Int ; 16(8): 983-9, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15551057

RESUMO

Mechanical loading is thought to provoke a cellular response via loading-induced flow of interstitial fluid through the lacuno-canalicular network of osteocytes. This response supposedly leads to an adaptation of local bone mass and architecture. It has been suggested that loss of estrogen during menopause alters the sensitivity of bone tissue to mechanical load, thereby contributing to the rapid loss of bone. The present study aimed to determine whether estrogen modulates the mechanoresponsiveness of bone cells from osteoporotic women. Bone cell cultures from nine osteoporotic women (aged 62-90 years) were pre-cultured for 24 h with 10(-11) mol/l 17beta-estradiol (E2) or vehicle, and subjected to 1 h of pulsating fluid flow (PFF) or static culture. E2 alone enhanced prostaglandin E(2) (PGE(2)) and nitric oxide (NO) production by 2.8-fold and 2.0-fold, respectively, and stimulated endothelial nitric oxide synthase protein expression by 2.5-fold. PFF, in the absence of E2, stimulated PGE(2) production by 3.1-fold and NO production by 3.9-fold. Combined treatment with E2 and PFF increased PGE(2) and NO production in an additive manner. When expressed as PFF-treatment-over-control ratio, the response to fluid shear stress was similar in the absence or presence of E2. These results suggest that E2 does not affect the early response to stress in bone cells. Rather, E2 and shear stress both promote the production of paracrine factors such as NO and PGE(2) in an additive manner.


Assuntos
Dinoprostona/biossíntese , Estrogênios/farmacologia , Óxido Nítrico/biossíntese , Osteoblastos/metabolismo , Osteoporose/metabolismo , Idoso , Idoso de 80 Anos ou mais , Células Cultivadas , Feminino , Humanos , Pessoa de Meia-Idade , Osteoblastos/efeitos dos fármacos , Osteoporose/patologia , Fluxo Pulsátil , Estresse Mecânico
20.
Bone ; 35(1): 186-90, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15207755

RESUMO

The purpose of this study was to examine the effect of mineralization on the mechanical properties of embryonic bone rudiments. For this purpose, four-point bending experiments were performed on unmineralized and mineralized embryonic mouse ribs at 16 and 17 days of gestational age. Young's modulus was calculated using force-displacement data from the experiment in combination with finite element analysis (FEA). For the unmineralized specimens, a calculated average for the Young's modulus of 1.11 (+/- 0.62) MPa was established after corrections for sticking to the four-point bending device and aspect ratio, which is the ratio between the length of the bone and its diameter. For the mineralized specimens, the value was 117 (+/- 62) MPa after corrections. Hence, Young's moduli of embryonic bone rudiments increase by two orders of magnitude within 1 day, during endochondral ossification. As an effect, the hypertrophic chondrocytes in the calcifying cartilage experience a significant change in their mechanical environment. The chondrocytes are effectively stress shielded, which means that they do not carry stresses since stresses are supported by the stiffest parts of the tissue, which are in this case the diaphyseal cortex and the calcified matrix. The deformability of the hypertrophic chondrocytes is, therefore, severely reduced. Since the transition is so sudden and enormous, it can be seen as a process of 'catastrophic' proportion for the hypertrophic chondrocytes. The subsequent resorption of calcified cartilage and the expansion of the marrow cavity could be consequential to stress shielding.


Assuntos
Densidade Óssea , Osso e Ossos/embriologia , Osso e Ossos/fisiologia , Animais , Fenômenos Biomecânicos , Cartilagem/embriologia , Cartilagem/fisiologia , Condrócitos/citologia , Idade Gestacional , Camundongos
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