Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 94
Filtrar
1.
BMC Vet Res ; 19(1): 116, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37559089

RESUMO

BACKGROUND: Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) syndrome is a dental disease where the radiographic signs may be quantified using radiographic texture features. This study aimed to implement the scaled-pixel-counting protocol to quantify and compare the image structure of teeth and the density standard in order to improve the identification of the radiographic signs of tooth resorption and hypercementosis using the EOTRH syndrome model. METHODS AND RESULTS: A detailed examination of the oral cavity was performed in 80 horses and maxillary incisor teeth were evaluated radiographically, including an assessment of the density standard. On each of the radiographs, pixel brightness (PB) was extracted for each of the ten steps of the density standard (S1-S10). Then, each evaluated incisor tooth was assigned to one of 0-3 EOTRH grade-related groups and annotated using region of interest (ROI). For each ROI, the number of pixels (NP) from each range was calculated. The linear relation between an original X-ray beam attenuation and PB was confirmed for the density standard. The NP values increased with the number of steps of the density standard as well as with EOTRH degrees. Similar accuracy of the EOTRH grade differentiation was noted for data pairs EOTRH 0-3 and EOTRH 0-1, allowing for the differentiation of both late and early radiographic signs of EOTRH. CONCLUSION: The scaled-pixel-counting protocol based on the use of density standard has been successfully implemented for the differentiation of radiographic signs of EOTRH degrees.


Assuntos
Doenças dos Cavalos , Hipercementose , Reabsorção de Dente , Cavalos , Animais , Hipercementose/veterinária , Incisivo/diagnóstico por imagem , Doenças dos Cavalos/diagnóstico , Reabsorção de Dente/diagnóstico por imagem , Reabsorção de Dente/veterinária , Radiografia Dentária/veterinária
2.
Endokrynol Pol ; 73(6): 917-921, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36519649

RESUMO

INTRODUCTION: In older people, depression and mental disability are more frequently present than in younger subjects. It is found that depressionis a risk factor for dementia, just as dementia is a risk factor for depression. In turn, both disturbances are known to be influenced by hormones. The present study aimed to see whether the hormonal changes in subjects over 75 years old correlate with the symptoms of depression measured using the Geriatric Depression Scale (GDS). MATERIAL AND METHODS: In a group of patients aged over 75 years, concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), oestradiol, testosterone, dehydroepiandrosterone sulphate (DHEAs), and cortisol were measured in serum with the use of chemiluminescence. The symptoms of depression were estimated by GDS, and the mental functions were assessed by the Mini-Mental State Examination (MMSE). The correlations between the obtained results were estimated by Spearman's test. RESULTS AND CONCLUSIONS: A significant correlation between GDS and MMSE scores was observed in the investigated patients. Some statistically significant correlations concerning cortisol and testosterone with GDS were observed in women, but not in men. On the other hand, no significant correlations between concentrations of FSH, LH, DHEAs, and oestradiol with GDS were noticed. Our data support the role of cortisol (possibly secreted during chronic stress) in the risk of depression. The gender difference in the mechanism of depression and stress in older age could be also hypothesized.


Assuntos
Depressão , Idoso , Feminino , Humanos , Masculino , Demência/etiologia , Demência/metabolismo , Depressão/etiologia , Depressão/metabolismo , Estradiol , Hormônio Foliculoestimulante , Hidrocortisona , Hormônio Luteinizante , Testosterona
3.
Front Endocrinol (Lausanne) ; 13: 1079043, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36686418

RESUMO

Introduction: Sex hormones may play an important role in age-related cardiac remodeling. However, their impact on cardiac structure and function in females of advanced age still remains unclear. The aim of this study is to evaluate the relationship between sex hormones level and echocardiographic parameters in older women with concomitant cardiovascular diseases. Materials and Methods: The study group included 52 community-dwelling women with mean age 79.5 ± 2.8 years, consecutive patients of an outpatient geriatric clinic. In all the subjects, a transthoracic echocardiogram was performed and serum testosterone, estradiol, follicle-stimulating hormone, luteinising hormone, dehydroepiandrosterone sulphate, and cortisol levels were determined. Results: Testosterone level correlated positively with interventricular septum diastolic dimension (IVSd) (rS=0.293, p<0.05), left ventricular mass index (rS=0.285, p<0.05), E/E' ratio (rS=0.301, p<0.05), and negatively with E' (rS=-0.301, p<0.05). Estradiol level showed a positive correlation with the posterior wall dimension (rS=0.28, p<0.05). Besides, no significant correlations between clinical or echocardiographic parameters and other hormones were observed. Female subjects with diagnosed left ventricular hypertrophy (LVH) (n=34) were characterized by a significantly higher rate of hypertension (p=0.011), higher waist-to-height ratio (p=0.009), higher testosterone level (0.82 vs. 0.48 nmol/L, p=0.024), higher testosterone/estradiol ratio (16.4 vs. 9.9, p=0.021), and received more anti-hypertensive drugs (p=0.030). In a multiple stepwise logistic regression, the best determinants of LVH were the presence of hypertension (OR=6.51; 95% CI 1.62-26.1), and testosterone level (OR= 6.6; 95% CI 1.19-36.6). Conclusions: Higher serum testosterone levels may contribute to pathological cardiac remodeling, especially in hypertensive women. Estradiol, gonadotropins, DHEAS, and cortisol were not related to echocardiographic parameters.


Assuntos
Hipertensão , Hipertrofia Ventricular Esquerda , Humanos , Feminino , Idoso , Idoso de 80 Anos ou mais , Hipertrofia Ventricular Esquerda/patologia , Hidrocortisona , Remodelação Ventricular , Hormônios Esteroides Gonadais , Testosterona , Estradiol
4.
Acta Bioeng Biomech ; 24(2): 141-152, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38314478

RESUMO

PURPOSE: The primary aim of the present study was to compare the bileaflet and trileaflet aortic valves' performance during uniform blood flow model and boundary conditions. The secondary aim of the study was to determine the effect of Newtonian/non-Newtonian fluid flow assumption on blood flow directly behind the trileaflet valve. METHODS: The geometrical model of the whole system consist of the left ventricle, fragment of the aorta and mechanical valves. A representation of pulsatile flow was obtained by measuring blood flow velocity (Doppler ultrasound examination). We have assumed turbulent blood flow. We considered two blood models, Newtonian and non-Newtonian (Carreau model). The valves' performance was assessed using the reduced stress in the valves, the shear stress in the aortic wall, flow velocity field and the effective orifice area. RESULTS: The maximum von Mises stress for the bileaflet valve leaflets was 0.3 MPa and for the trileaflet valve - 0.06 MPa. The maximum flow velocity for the bileaflet valve was 4.52 m/s for 40° and for the trileaflet valve - 5.74 m/s. Higher shear stress was present in the bileaflet (151.5 Pa) than for the trileaflet valve (49.64 Pa). CONCLUSIONS: The results indicate that central blood jet for the trileaflet valve contributes to more physiological blood flow and decreases the risk of haemolysis. The central flow minimises the risk of leaflet dislocation. In addition, lower stresses extend the durability of the valve. However, the trileaflet valve geometry has also disadvantages, for instance, small peripheral streams or relatively low effective orifice area.

5.
Acta Bioeng Biomech ; 24(3): 169-177, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38314487

RESUMO

PURPOSE: The aim of this research was to verify to what extent the shape of an indenter tip influences the final form of the constitutive equation for the trabecular bone. METHODS: Trabecular bone was formulated as a non-linear viscoelastic material with Mooney-Rivlin hyperelastic model to describe the purely elastic response of the bone tissue. Tests of the mechanical properties of the trabecular bone, resected from the femoral head of a 56-year-old patient, were carried out with two types of indenter: the spherical tip of a diameter of 200 µm and pyramid Vickers tip with 136° between plane faces. Tests with both indenters included loading and unloading phases with no hold at peak force and with hold time t = 20 s and were conducted with a maximum load Pmax = 500 mN and loading/unloading rate V = 500 mN/min. RESULTS: The formulated constitutive model describes the trabecula behaviour very well. The model curves match the experimental results in the loading phase, holding period and most of the unloading ramp. The purely viscoelastic material constants are very close in value for both considered tips, but purely elastic constants differ. CONCLUSIONS: The results indicate that the constitutive model based on the indentation with the Vickers tip does not cover the plastic residual deformation. When a viscoelastic response of bone is expected, a model with constants calibrated for the spherical tip should be used, and the other set of parameters values (Vickers tip) when trabeculae may undergo plastic deformation.

6.
Molecules ; 26(23)2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34885747

RESUMO

There is experimental evidence of high vibronic activity that accompanies the allowed transition between the ground state and the lowest electronic singlet excited state of oligofurans that contain two, three, and four furan rings. The absorption and emission spectra of the three lowest oligofurans measured at liquid nitrogen temperature show distinct fine structures that are reproduced using the projection-based model of vibronic coupling (with Dushinsky rotation included) parameterized utilizing either Density Functional Theory (DFT, with several different exchange-correlation functionals) or ab initio (CC2) quantum chemistry calculations. Using as a reference the experimental data concerning the electronic absorption and fluorescence for the eight lowest oligofurans, we first analyzed the performance of the exchange-correlation functionals for the electronic transition energies and the reorganization energies. Subsequently, we used the best functionals alongside with the CC2 method to explore how the reorganization energies are distributed among the totally symmetric vibrations, identify the normal modes that dominate in the fine structures present in the absorption and emission bands, and trace their evolution with the increasing number of rings in the oligofuran series. Confrontation of the simulated spectra with the experiment allows for the verification of the performance of the selected DFT functionals and the CC2 method.

7.
Endokrynol Pol ; 72(3): 256-260, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34010445

RESUMO

The paper presents the theoretical considerations on the role of endocrine and metabolic alterations accompanying COVID-19 infection. These alterations may be presumed on the basis of the following two observations. Firstly, the virus SARS-CoV-2 responsible for the COVID-19 infection uses an important renin-angiotensin system (RAS) element - angiotensin-converting enzyme 2 (ACE2) - as a receptor protein for entry into target cells and, in consequence, disturbs the function of the main (circulating) renin-angiotensin-aldosterone system (RAAS) and of the local renin-angiotensin system localized in different tissues and organs. The binding of SARS-CoV-2 to ACE2 leads to the downregulation of this enzyme and, in the aftermath, to the excess of angiotensin II and aldosterone. Thus, in the later stage of COVID-19 infection, the beneficial effects of ACEI and ARB could be presumed. It is hypothesized that the local RAS dysregulation in the adipose tissue is the main cause of the negative role of obesity as a risk factor of severe outcome of the COVID-19 infection. Secondly, the outcome of COVID-19 strongly depends on the age of the patient. Age-related hormonal deficiencies, especially those of melatonin and dehydroepiandrosterone, may contribute to morbidity/mortality in older people. The usefulness of melatonin and angiotensin converting enzyme inhibitors/angiotensin receptor 1 blockers (the latter only in later phases of the infection) as adjuvant drugs is probable but needs thorough clinical trials.


Assuntos
COVID-19/metabolismo , Sistema Renina-Angiotensina , Envelhecimento , Aldosterona , Angiotensina II , Enzima de Conversão de Angiotensina 2 , COVID-19/enzimologia , COVID-19/fisiopatologia , Diabetes Mellitus , Humanos , Melatonina , Obesidade
8.
Front Endocrinol (Lausanne) ; 12: 797243, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35002975

RESUMO

Many hormones fluctuate during the aging process. It has been suggested that gonadotropins, which increase with age, contribute to the occurrence of many diseases and syndromes in older life, such as cardiovascular diseases, obesity, frailty syndrome and osteoporosis. This study aims to assess the relationship between circulating gonadotropins and other hormones potentially contributing to age-related functional decline and sarcopenia indicators in 39 male and 61 female community-dwelling seniors, mean age 80 years. According to the definition developed by the second European Working Group on Sarcopenia in Older People (EWGSOP2), the following indicators of the sarcopenia were assessed: bioimpedance-measured body composition, gait speed, handgrip strength, timed up and go test (TUG), chair stand test, Short Physical Performance Battery (SPPB). Blood levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, testosterone, dehydroepiandrosterone sulphate (DHEAS) and cortisol were also measured. In the men, FSH and partially LH correlated positively with muscle mass percentage, gait speed, handgrip strength and SPPB, and negatively with percent body fat. Additionally, testosterone and DHEAS correlated negatively with the percentage of fat mass in men. Whereas in the women, FSH and LH were mainly negatively associated with body mass and adipose tissue measures. Cortisol did not show any relationship with the examined indicators. The study shows that the indicators of sarcopenia are strongly associated with levels of gonadotropins, sex hormones and DHEAS, especially in older men. The obtained results, after being confirmed in a larger group, may modify prevention and treatment strategies of sarcopenia.


Assuntos
Composição Corporal/fisiologia , Gonadotropinas/sangue , Força da Mão/fisiologia , Vida Independente , Músculo Esquelético/metabolismo , Sarcopenia/sangue , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Humanos , Masculino , Projetos Piloto , Sarcopenia/diagnóstico , Sarcopenia/epidemiologia
9.
Neuro Endocrinol Lett ; 41(3): 118-122, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33201648

RESUMO

The paper presents the evaluation of a hypothesis assuming that the elevated levels of gonadotropins which occur physiologically in older persons are involved by their direct extra-gonadal action in the pathogenesis of age-related disorders. The data on the possibilities of the direct action of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and their possible deleterious effects in the brain, bone, cardiovascular system and cancer in older persons are reviewed. A proposal of a new approach to the hormonal prevention treatment of age-related disorders (suppression of gonadotropins by means of gonadotropin releasing hormone analogs) is discussed.


Assuntos
Envelhecimento , Doença/etiologia , Gonadotropinas/metabolismo , Idoso , Doenças Cardiovasculares/etiologia , Feminino , Hormônio Foliculoestimulante/metabolismo , Humanos , Hormônio Luteinizante/metabolismo , Masculino , Transtornos da Memória/etiologia , Obesidade/etiologia , Osteoporose/etiologia
10.
Folia Histochem Cytobiol ; 58(2): 90-95, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32597492

RESUMO

INTRODUCTION: Approximately one third of pituitary adenomas are manifested neither by specific symptoms of hormone overproduction nor by elevated blood levels of pituitary hormones. However, these tumours, diagnosed before surgical intervention as clinically non-functioning pituitary adenomas (CNFPAs) express in majority different pituitary hormones, as can be revealed by means of immunohistochemical examination. One of the pituitary hormones which may be expressed in CNFPAs is prolactin (PRL) but the clinical and pathological data on this condition are very scarce. MATERIAL AND METHODS: Sixty two pituitary adenomas, diagnosed before surgery as CNFPAs, were immunoassayed with antibodies against PRL, growth hormone (GH), luteinizing hormone (LH), follicle stimulating hormone (FSH), thyrotropin (TSH), alpha subunit (alpha-SU), corticotropin (ACTH) and dopamine receptor type 2. In a proportion of the patients the presurgical concentrations of insulin-like growth factor 1 (IGF-1) were estimated by means of enzyme-amplified chemiluminescence assay. RESULTS: Twenty-three (37.1%) of the examined CNFPAs presented the positive immunoreaction with anti-PRL antibody. Most cases concerned women. Only in two cases (one woman and one man), PRL was the unique hormone expressed in the tumour. In the remaining adenomas PRL immunopositivity was accompanied by GH expression - 17, LH or free bLH - 13, FSH - 2, free a subunit - 4 or by ACTH - 5 tumours. Seven (30.43%) of them were recurrent in comparison with 12.8% PRL-immunonegative recurrent CNFPAs. Dopamine receptors were positively immunostained in all the investigated PRL-immunopositive and all PRL-immunonegative adenomas. CONCLUSIONS: Our data confirm the observations that monohormonal silent prolactinomas are very rare but frequently silent PRL often co-expressed with GH or LH. Although in the whole population of patients with CNFPAs both sexes are equally represented, in the case of silent prolactinomas the female sex is prevalent. The observation of the higher rate of recurrent tumours within PRL-immunopositive adenomas versus PRL-immunonegative CNFPAs has to be confirmed on the larger material.


Assuntos
Neoplasias Hipofisárias/diagnóstico , Prolactina/análise , Prolactinoma/diagnóstico , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/patologia , Prolactinoma/patologia
11.
Neuro Endocrinol Lett ; 41(1): 27-32, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32338850

RESUMO

BACKGROUND: Aging is characterized by deep alterations of hormone secretion. In majority, hormone secretion, except gonadotropins, undergoes a pronounced decrease which is thought to contribute to the progression of aging. The recent data indicate that gonadotropin excess may also by itself influence the aging process. The aim of the present study was to investigate the relations between gonadotropins and steroid hormones with physical and mental abilities of older people. MATERIAL AND METHODS: In a group of patients aged over 75 years, concentrations of FSH, LH, estradiol, testosterone, DHEAs and cortisol were measured. The mental ability was estimated by MMSE and CDT and the physical ability by TUG and SPPB tests. RESULTS AND CONCLUSIONS: The positive correlation between SPPB scores and FSH and the negative correlations of SPPB with LH/FSH ratio were observed in men. The correlation of TUG scores and estradiol levels was also noted in men. The positive correlation between CDT scores and FSH in women and the negative correlation between CDT and LH/FSH ratio in men were found. The correlation between the results of CDT and cortisol levels in men was also observed. Thus, we did not confirm the simple deleterious effect of gonadotropins on cognitive abilities. FSH and LH seem exert different (antagonistic?) effects on cognitive functions, but this hypothesis needs further studies.


Assuntos
Envelhecimento/fisiologia , Cognição/fisiologia , Hormônios Esteroides Gonadais/sangue , Gonadotropinas/sangue , Aptidão Física/fisiologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/sangue , Envelhecimento/psicologia , Sulfato de Desidroepiandrosterona/sangue , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Hormônio Luteinizante/sangue , Masculino , Competência Mental/psicologia , Saúde Mental , Polônia , Testosterona/sangue
12.
Endokrynol Pol ; 70(5): 437-444, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31681968

RESUMO

Pituitary hormones folitropin (follicle-stimulating hormone, FSH) and lutropin (luteinising hormone, LH) are known as the key regulators of human reproduction. However, their receptors have been identified also in several organs and tissues beyond the reproductive system, and there is cumulating evidence of their direct extra-gonadal actions. The expression of LH receptors (LHR) was found in the brain and adrenal cortex. FSH receptors (FSHR) were found to be expressed in osteoclasts, monocytes, adipocytes, and peri- and intra-tumoural blood vessel endothelia of malignant tumours. Other localisations of FSHR and LHR are also suggested by immunohistochemistry, but these findings need confirmation using molecular biology techniques. Because the high levels of gonadotropins are a constant phenomenon during human aging, especially in postmenopausal women, it is hypothesised that the direct actions of FSH and LH are involved in the pathogenesis of age-related disorders. The proposal of therapy based on the inhibition of gonadotropin hypersecretion is also discussed.


Assuntos
Hormônio Liberador de Gonadotropina/metabolismo , Hormônio Luteinizante/metabolismo , Receptores do FSH/metabolismo , Receptores do LH/metabolismo , Envelhecimento/metabolismo , Feminino , Hormônio Liberador de Gonadotropina/deficiência , Gonadotropinas/metabolismo , Humanos , Sistema Hipotálamo-Hipofisário/metabolismo , Hormônio Luteinizante/deficiência , Masculino
13.
Folia Histochem Cytobiol ; 57(1): 23-27, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30924919

RESUMO

INTRODUCTION: Numerous data indicate that luteinizing hormone and/or chorionic gonadotropin (LH/CG) exert direct actions on the adrenal cortex and are involved in the adrenal pathology. However, the immunohistochemical studies on the expression of LH/CG receptors (LH/CGR) in the human adrenal cortex and in the adrenocortical tumors are scarce. MATERIAL AND METHODS: Paraffin sections of samples of 6 human non-neoplastic adrenal cortex and 25 adrenocortical tumors were immunostained with anti-LH/CGR polyclonal antibody. RESULTS: All zones of the human non-neoplastic adrenal cortex present a positive immunoreaction with anti-LH/CGR antibody showing the strongest reaction in cell membranes. The LH/CGR immunostaining in the vast majority of hormonally non-functioning adenomas and in all hormone-secreting adenomas does not differ from the non-neoplastic adrenal cortex. In contrast to non-neoplastic adrenal cortex and benign adenomas, in adrenocortical cancers the immunostaining with anti-LH/CGR antibody behaves differently. The immunopositive material is almost totally filling the cytoplasm of the cells but the immunopositivity of cell membranes is weak or lacking. CONCLUSIONS: The data presented in our study show that the expression of LH/CGR in adrenocortical tumors is not ectopic but eutopic. The immunohistochemical examination of LH/CGR may be useful in the differentiation between benign and malignant lesions in the adrenal cortex. Moreover, the loss of membrane localization of LH/CGR in adrenocortical cancer suggests the alteration of receptors' function.


Assuntos
Neoplasias do Córtex Suprarrenal/metabolismo , Córtex Suprarrenal/metabolismo , Receptores do LH/metabolismo , Córtex Suprarrenal/citologia , Neoplasias do Córtex Suprarrenal/patologia , Anticorpos/imunologia , Humanos , Imuno-Histoquímica , Receptores do LH/imunologia
14.
Endokrynol Pol ; 70(3): 237-240, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30699231

RESUMO

INTRODUCTION: The α-Klotho protein was discovered as a gene controlling the process of aging, but further studies indicated that it also plays the role of a tumour suppressor. Although numerous studies were performed on the role of the α-Klotho gene and protein in neoplasia, the data on α-Klotho protein expression in thyroid cancers are very scarce. Our study presents the immunohistochemical investigation of α-Klotho expression in benign and malignant thyroid tumours. MATERIAL AND METHODS: The material included samples of benign (nodular hyperplasia, follicular adenoma), differentiated (follicular and papillary) cancers and aggressive thyroid cancers of low differentiation grade. The samples were immunostained using two different monoclonal anti-α-Klotho antibodies. RESULTS: From the two antibodies used in this study, one (EPR6856) reacted probably with the soluble form of Klotho and immunostained mostly the colloid filling thyroid follicles and intravascular or extravascular serum deposits. The other (A-9 antibody) immunostained the follicular epithelium in benign thyroid lesions as well as the epithelial tumoural cells in differentiated thyroid (follicular and papillary cancers). In the thyroid cancers of high malignancy, the immunostaining with A-9 anti-α-Klotho antibody was (except in one case) negative or very weak. CONCLUSION: Our results indicate that lowered expression of a- Klotho is involved in the process of thyroid neoplasia.


Assuntos
Regulação Neoplásica da Expressão Gênica , Glucuronidase/genética , Neoplasias da Glândula Tireoide/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Proteínas Klotho , Masculino , Pessoa de Meia-Idade , Neoplasias da Glândula Tireoide/genética , Adulto Jovem
15.
J Mech Behav Biomed Mater ; 85: 162-169, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29902776

RESUMO

A new constitutive model for human trabecular bone is presented in the present study. As the model is based on indentation tests performed on single trabeculae it is formulated in a microscale. The constitutive law takes into account non-linear viscoelasticity of the tissue. The elastic response is described by the hyperelastic Mooney-Rivlin model while the viscoelastic effects are considered by means of the hereditary integral in which stress depends on both time and strain. The material constants in the constitutive equation are identified on the basis of the stress relaxation tests and the indentation tests using curve-fitting procedure. The constitutive model is implemented into finite element package Abaqus® by means of UMAT subroutine. The curve-fitting error is low and the viscoelastic behaviour of the tissue predicted by the proposed constitutive model corresponds well to the realistic response of the trabecular bone.


Assuntos
Osso Esponjoso , Teste de Materiais , Fenômenos Mecânicos , Fenômenos Biomecânicos , Calibragem , Fêmur , Humanos
16.
Acta Bioeng Biomech ; 19(2): 79-91, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28869620

RESUMO

PURPOSE: The goal of the study was to determine the influence of DSI test conditions, i.e., loading/unloading rates, hold time, and the value of the maximum loading force on selected mechanical properties of trabecular bone tissue. METHODS: The test samples were resected from a femoral head of a patient qualified for a hip replacement surgery. During the DSI tests hardness (HV, HM, HIT) and elastic modulus (EIT) of trabecular bone tissue were measured using the Micro Hardness Tester (MHT, CSEM). RESULTS: The analysis of the results of measurements and the calculations of total energy, i.e., elastic and inelastic (Wtotal, Welastic, Winelastic) and those of hardness and elasticity made it possible to assess the impact of the process parameters (loading velocity, force and hold time) on mechanical properties of bone structures at a microscopic level. CONCLUSIONS: The coefficient k dependent on the EIT/HIT ratio and on the stored energy (ΔW = Wtotal - Welastic) is a measure of the material reaction to the loading and the deformation of tissue.


Assuntos
Densidade Óssea/fisiologia , Transferência de Energia/fisiologia , Fêmur/fisiologia , Testes de Dureza/métodos , Modelos Biológicos , Força Compressiva/fisiologia , Simulação por Computador , Módulo de Elasticidade/fisiologia , Dureza/fisiologia , Humanos , Estresse Mecânico , Resistência à Tração/fisiologia
17.
Wiad Lek ; 69(3 Pt 1): 333-4, 2016.
Artigo em Polonês | MEDLINE | ID: mdl-27486711

RESUMO

A discussion of causes of dehumanisation in contemporary medicine and possible methods of preventing this situation. The causes can be divided into external, associated with the influence of the environment of civilisation, and internal, which constitute a form of aunwanted side effects" of the rapid progress of civilisation. The latter include reductionist thinking and axiological neutrality typical of natural sciences, increased import_ance of technology, and excessive specialisation combined with poor coordination of diagnostic work-up and treatment or the lack of such coordination. Possible preventive measures include a change in the model of medical education, consisting for instance in the inclusion of humanistic elements and a more holistic view of the patient, as well as a change in the health care model so that the diagnostic work-up and treatment would be coordinated mainly by the primary health care doctor.


Assuntos
Desumanização , Ética Médica , Medicina Baseada em Evidências , Prestação Integrada de Cuidados de Saúde , Humanos , Autonomia Pessoal
18.
Endokrynol Pol ; 67(5): 515-518, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27403655

RESUMO

INTRODUCTION: The pituitary adenomas secreting thyrotropin (TSH) are considered the rarest type of hormonally active pituitary tumour. In spite of that, many cases are described in the literature. On the other hand, the observations of the co-expression of TSH with other pituitary hormones (mostly with growth hormone [GH]) and "silent" expression of TSH in clinically non-functioning pituitary adenomas (CNFPA) are rather scarce. MATERIAL AND METHODS: Among 93 examined pituitary adenomas, 22 of them were diagnosed as active acromegaly and 71 as clinically non-functioning pituitary adenomas (CNFPA). All of them were immunostained with antibodies against pituitary hormones, including the anti-TSH antibody. TSH-immunopositive adenomas are immunostained also to detect somatostatin receptor subtypes (SSTR 1-5). RESULTS: TSH immunopositivity was found in 4.2% of CNFPA (3/71 tumours) and in 13.6% (3/22) cases of somatotropinomas manifesting as active acromegaly. All of the examined TSH-immunopositive adenomas expressed SSTR subtypes except SSTR4. The symptoms of hyperthyroidism were not observed in any of the acromegalic patients co-expressing TSH with GH. CONCLUSIONS: Our data confirm the relative rarity of TSH expression or co-expression of TSH in pituitary tumours. In most cases TSH is co-expressed with GH in patients with acromegaly and is not accompanied by hyperthyroidism. The "silent" expression of TSH may occur also, although rarely in CNFPA. The strong expression of SSTR in TSH-immunopositive CNFPA ("silent thyrotropinoma") indicates the possibility of the treatment of these tumours with somatostatin analogues. (Endokrynol Pol 2016; 67 (5): 515-518).


Assuntos
Acromegalia/metabolismo , Adenoma/metabolismo , Neoplasias Hipofisárias/metabolismo , Tireotropina/metabolismo , Acromegalia/etiologia , Adenoma/complicações , Adulto , Feminino , Hormônio do Crescimento Humano/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/complicações , Receptores de Somatostatina/metabolismo , Adulto Jovem
19.
Endokrynol Pol ; 67(3): 292-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27345147

RESUMO

INTRODUCTION: Non-functioning pituitary adenomas (NFPA) are often diagnosed late as invasive macroadenomas. The surgical resection is usually incomplete and about 50% of patients require additional surgery. Recent data suggest that somatostatin analogues (SSA), so important in the pharmacotherapy of acromegaly, can also be effective in the management of NFPA. MATERIAL AND METHODS: We analysed data of patients who had been treated up to 10 years previously with SSA: 40 with acromegaly (23 - primary, 17 - recurrent tumours) and 22 with NFPA (4 - primary, 18 - recurrent tumours). Hormonal profile, dynamics of tumour size change, ophthalmic syndromes, somatostatin receptor (SSTR) scintigraphy, and immunohistochemistry of SSTR subtypes of operated tumours as well as side effects were investigated. RESULTS: Biochemical cure of acromegaly was achieved in 57.5% of patients, while reduction of tumour size was observed in 37% of patients and it was more frequent in not-operated cases. Regarding NFPA, stabilisation of tumour size was noticed in 68% of patients. Tumour shrinkage was reported in 9% of cases, but in 23% of the study group the adenoma size increased with indication for reoperation. CONCLUSIONS: The efficacy of SSA in NFPA is much lower in comparison to their well-established effects in the treatment of acromegaly. Stabilisation of tumour size, which is observed in the majority of NFPA, is significantly more frequent in comparison to the natural history of untreated NFPA and our previous studies as well. Analysis of SSTR subtypes is an argument in favour of introduction of novel broad-spectrum SSA that may be more effective in the treatment of NFPA. Referring to acromegaly, adenoma size decrease was reported more frequently in primary therapy. Considering recurrent tumours better outcomes were achieved in patients who were pre-treated with SSA before planned surgery. (Endokrynol Pol 2016; 67 (3): 292-298).


Assuntos
Acromegalia/tratamento farmacológico , Neoplasias Hipofisárias/tratamento farmacológico , Somatostatina/análogos & derivados , Adenoma/diagnóstico , Adenoma/tratamento farmacológico , Adenoma/cirurgia , Adulto , Idoso , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/diagnóstico , Neoplasias Hipofisárias/cirurgia , Cintilografia , Somatostatina/efeitos adversos , Somatostatina/uso terapêutico , Resultado do Tratamento
20.
Thyroid Res ; 8(1): 1, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25685198

RESUMO

BACKGROUND: In normal conditions FSHR are expressed in granulosa cells of the ovary and Sertoli cells of the testis. They can be expressed also in gonadal tumours. However, recently the expression of FSHR was found in tumoral cells and intra-tumoral blood vessels of many other tumours, including thyroid tumours. Aim of this study was to see whether the expression of FSHR can be useful in the differentiation of benign and malignant thyroid lesions. METHODS: 44 samples of surgically excised thyroids were immunostained with anti- FSHR antibody raised against 1-190 amino acid sequence from the human FSHR. RESULTS: Non-neoplastic thyroid follicles (i.e. the follicles situated outside the tumour) do not show the immunostaining for FSHR. The same concerns the majority of follicular adenomas. In contrast, 87.5% of follicular cancers, the same percentage of papillary cancers and all the examined undifferentiated cancers showed the FSHR immunopositivity of tumoral cells. A tendency towards the higher frequency of FSHR - positive blood vessels also concerns malignant thyroid tumours. CONCLUSIONS: The ectopic FSHR immunostaining seems to be useful to differentiate malignant from benign lesions, especially follicular cancers from follicular adenomas. However, the further studies on larger material are needed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...