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The 2nd International Conference on Controversies in Vitamin D was held in Monteriggioni (Siena), Italy, September 11-14, 2018. The aim of this meeting was to address ongoing controversies and timely topics in vitamin D research, to review available data related to these topics and controversies, to promote discussion to help resolve lingering issues and ultimately to suggest a research agenda to clarify areas of uncertainty. Several issues from the first conference, held in 2017, were revisited, such as assays used to determine serum 25-hydroxyvitamin D [25(OH)D] concentration, which remains a critical and controversial issue for defining vitamin D status. Definitions of vitamin D nutritional status (i.e. sufficiency, insufficiency and deficiency) were also revisited. New areas were reviewed, including vitamin D threshold values and how they should be defined in the context of specific diseases, sources of vitamin D and risk factors associated with vitamin D deficiency. Non-skeletal aspects related to vitamin D were also discussed, including the reproductive system, neurology, chronic kidney disease and falls. The therapeutic role of vitamin D and findings from recent clinical trials were also addressed. The topics were considered by 3 focus groups and divided into three main areas: 1) "Laboratory": assays and threshold values to define vitamin D status; 2) "Clinical": sources of vitamin D and risk factors and role of vitamin D in non-skeletal disease and 3) "Therapeutics": controversial issues on observational studies and recent randomized controlled trials. In this report, we present a summary of our findings.
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Deficiência de Vitamina D/complicações , Vitamina D/sangue , Doença Celíaca , Diabetes Mellitus , Suplementos Nutricionais , Fraturas Ósseas , Humanos , Esclerose Múltipla , Neoplasias , Doenças Neurodegenerativas , Obesidade , Osteoporose , Vitamina D/efeitos adversos , Vitamina D/metabolismo , Vitamina D/uso terapêutico , Deficiência de Vitamina D/tratamento farmacológicoRESUMO
PURPOSE OF REVIEW: This review focuses on the pathophysiological and clinical aspects of diabetes mellitus occurring in patients with Cushing disease (CD). RECENT FINDINGS: Insulin resistance and impairment in insulin secretion are both involved in the pathogenesis of glucocorticoid-induced diabetes. Correction of glucocorticoid excess does not always resolve abnormalities of glucose homeostasis, and correction of hyperglycaemia is specifically required. In fact, insulin resistance may persist even after correction of glucocorticoid excess and diabetes needs to be treated for long term. On the other hand, emerging drugs used in the treatment of CD, such as the novel somatostatin analog pasireotide, may have direct effects on glucose homeostasis regardless of control of cortisol excess. Diabetes mellitus is a frequent and early complication of CD with important diagnostic, prognostic and therapeutic implications. Specifically, diagnosis of CD in patients with diabetes may be difficult due to potential misinterpretation of markers of cortisol hypersecretion. Moreover, diabetes mellitus is often difficult to be controlled in CD requiring a careful and dedicated therapeutic approach. Finally, the coexistence of diabetes may influence the therapeutic decision making in CD, since drugs used in this setting may variably influence glucose homeostasis regardless of control of hypercortisolism.
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Diabetes Mellitus/tratamento farmacológico , Hipersecreção Hipofisária de ACTH/complicações , Hormônio Adrenocorticotrópico/metabolismo , Diabetes Mellitus/etiologia , Diabetes Mellitus/metabolismo , Humanos , Resistência à Insulina , Somatostatina/análogos & derivados , Somatostatina/uso terapêuticoRESUMO
INTRODUCTION: Growth hormone deficiency is considered the most important factor determining skeletal fragility in hypopituitary patients. Osteoblasts and chondrocytes express growth hormone (GH) receptor. Two GH receptor isoforms (GHRi) have been identified: they differ for the presence/absence of a protein fragment encoded by exon 3 of GHR gene. Consequently, three genotypes were identified: carriers of both the full-length proteins (flfl-GHR), carriers of one full-length protein and one deleted protein (fld3-GHR) and carriers of both deleted proteins (d3d3-GHR). This polymorphism confers a higher sensitivity to endogenous GH and to recombinant human GH (rhGH); its effect on bone metabolism and skeletal fragility is unknown. The aim of this article was to investigate the role of GHRi in predicting skeletal fragility in adult-onset GHD (AO-GHD) patients. SUBJECTS AND METHODS: A cross-sectional study was conducted to investigate the association between the d3-GHR isoform and the prevalence of morphometric vertebral fractures (VFs) in AO-GHD. Ninety-three AO-GHD were enrolled. Forty-nine patients carried flfl-GHRi (52·7%), and 44 patients (47·3%) carried at least one allele of the d3-GHR isoform. Thirty-two VFs were documented. Fifty-seven patients underwent rhGH replacement therapy. RESULTS: Median age was significantly higher in fractured patients as compared to nonfractured ones; d3-carrier patients showed a lower VF risk as compared to flfl-GHRi (OR: 0·37, 95% IC: 0·24-0·55, P < 0·0001). This finding was also confirmed in AO-GHD undergoing rhGH replacement therapy. CONCLUSION: This study suggests that d3-GHR may protect AO-GHD particularly when treated with rhGH from the risk of VFs.
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Fraturas Ósseas/genética , Hormônio do Crescimento Humano/deficiência , Receptores da Somatotropina/genética , Adulto , Idoso , Estudos Transversais , Feminino , Fraturas Ósseas/etiologia , Deleção de Genes , Genótipo , Terapia de Reposição Hormonal/métodos , Hormônio do Crescimento Humano/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Isoformas de Proteínas/genética , Proteínas Recombinantes/uso terapêutico , Adulto JovemRESUMO
BACKGROUND: The majority of clinicians suggest that enteral feedings should be held 1-2 h prior to and after L-T4 administration despite lack of data for continuous enteral nutrition. AIM: The aim of this study was to: (1) compare the thyroid hormonal profile in patients submitted to L-T4 treatment in tablets or liquid formulation with an enteral feeding tube; (2) evaluate the nursing compliance with the two different formulations. SUBJECTS AND METHODS: 20 euthyroid patients submitted to total laryngectomy and thyroidectomy consecutively started L-T4 treatment in tablets (Group T) or in liquid formulation (Group L) with enteral feeding tube the day after surgery. Tablets were crushed before administration and enteral feeding was stopped for 30 min before and after L-T4 treatment, whereas liquid formulation was placed into the nasoenteric tube immediately. A questionnaire about the preparation and administration of thyroxine replacement therapy was given to the nurses. RESULTS: No difference of TSH, fT4 and fT3 before and after L-T4 treatment was observed among patients of Group L. A slightly serum TSH increase was observed in Group T, but not reaching statistical significance (2.50 ± 1.18 vs 2.94 ± 1.22 mUI/L), whereas no difference in fT4 and fT3 levels was found. Preparation and administration of liquid L-T4 was considered excellent by 12/13 nurses, whereas tablet formulation was considered poor by 10/13. CONCLUSIONS: Our data showed that liquid L-T4 formulation can be administered directly through feeding tube with no need for an empty stomach, with a significant improvement in therapy preparation and administration by nurses.
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Formas de Dosagem , Tiroxina/administração & dosagem , Tiroxina/sangue , Idoso , Nutrição Enteral , Feminino , Humanos , Laringectomia , Masculino , Pessoa de Meia-Idade , Comprimidos , Tireoidectomia , Tiroxina/uso terapêuticoRESUMO
BACKGROUND: High resolution ultrasonography features have also been described as having a useful supporting role in the diagnosis of subacute granulomatous thyroiditis (ST), and images are generally characterized by heterogeneous hypoechoic areas of the affected tissue with lack of flow on color Doppler US. PURPOSE: To determine the sonographic features of subacute granulomatous thyroiditis. MATERIAL AND METHODS: We reviewed the medical records of patients referred at the Endocrine and Metabolic Unit of our Institution between January 2010 and December 2011. RESULTS: A total of 7520 patients were evaluated in our department between January 2010 and December 2011. Among them, 22 (0.3%) patients had a diagnosis of ST (19 women and 3 men, 45.4 ± 9.7 year; range, 33-62 years). Ultrasound examination showed bilateral ST in 64% of patients. Thyroid volume was 13.2 ± 7.7 mL, without difference if ST was unilateral (13.2 ± 7.1 mL) or bilateral (13.9 ± 8.3 mL). On grayscale US, heterogeneous diffusely or focally marked hypoechoic areas, like "lava flow", were found in all the lesions. CONCLUSION: Our data confirm the high sensitivity of US in the diagnosis of ST: diffuse hypoechoic and confluent areas with the characteristic features like "lava flow".
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Tireoidite Subaguda/diagnóstico por imagem , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tireoidite Subaguda/patologia , UltrassonografiaRESUMO
BACKGROUND: Late-onset glycogenosis type II (GSD II) is a rare, multisystem disorder mainly affecting limb and respiratory muscles due to acid alpha glucosidase deficiency. Despite evidence at autopsy of glycogen accumulation in the brain, no study exploring brain functions is yet available. OBJECTIVE: Our objective in this study was to assess brain changes in late-onset GSD II. METHODS: Each patient underwent a standardized neuropsychological assessment, regional grey-matter (GM) atrophy, and resting-state functional magnetic resonance imaging (RS-fMRI). Functional connectivity maps of the salience (SN) and default-mode (DMN) networks were considered. A group of age- and gender-matched healthy controls was enrolled for MRI comparisons. P values family-wise error (FWE) cluster level corrected inferior to 0.05 were considered. RESULTS: Nine GSD II patients (age 46.6 ± 8.0; 55% male) were recruited. No significant GM atrophy was found in patients compared with controls (n = 18; age 48.0 ± 9.8,;40% male). Functional connectivity within the SN was selectively reduced in patients, and cingulate gyrus and medial frontal cortex were mainly involved. Accordingly, patients had significant impairment of executive functions (as measured by Wisconsin Card Sorting test), whereas other cognitive domains were within mean normal ranges. CONCLUSIONS: Our findings extend the clinical spectrum of GSD II by indicating that brain changes occur in this muscular disorder. Above all, these results should lead to better examinations of therapeutic approaches and perspectives for the affected patients. Further studies evaluating in depth these issues are warranted.
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Encéfalo/patologia , Doença de Depósito de Glicogênio Tipo II/diagnóstico , Doença de Depósito de Glicogênio Tipo II/patologia , Adulto , Idade de Início , Encéfalo/fisiopatologia , Estudos de Casos e Controles , Feminino , Neuroimagem Funcional/métodos , Doença de Depósito de Glicogênio Tipo II/epidemiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
AIM: To compare the feasibility, accuracy, and effective radiation dose (ED) of multidetector computed tomography (MDCT) in the detection of coronary artery disease using a combined ED-saving strategy including prospective electrocardiogram (ECG) triggering with a short x-ray window and a body mass index (BMI)-adapted imaging protocol using adaptive statistical iterative reconstruction (ASIR; group 1), in comparison with a prospective ECG triggering strategy alone (group 2). MATERIALS AND METHODS: One hundred and seventy patients scheduled for invasive coronary angiography (ICA) were evaluated. Fourteen patients were not eligible for MDCT. The remaining 156 patients were randomized to group 1 (78 patients) and group 2 (78 patients). Eight and 11 patients in groups 1 and 2, respectively, were excluded after randomization because the patients' heart rates were >65 beats/min. MDCT images were assessed for feasibility, signal-to-noise ration (SNR), and contrast-to-noise ratio (CNR), accuracy in detection of coronary stenoses >50% versus ICA and for ED. RESULTS: The feasibility, SNR, CNR, accuracy in a segment-based and patient-based model were similar in both groups (97 versus 95%, 14.5 ± 3.9 versus 14.2 ± 4.1, 16 ± 4.6 versus 16.5 ± 4.4, 95 versus 94% and 97 versus 99%, respectively). The ED in group 1 was 72% lower than in group 2 (2.1 ± 1.2 versus 7.5 ± 1.8 mSv, respectively; p<0.01). CONCLUSIONS: The use of a multi-parametric ED saving protocol results in a significant reduction in ED without a negative impact on accuracy.
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Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Eletrocardiografia , Tomografia Computadorizada Multidetectores/métodos , Idoso , Algoritmos , Índice de Massa Corporal , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador , Sensibilidade e Especificidade , Fatores de TempoAssuntos
Epilepsia do Lobo Temporal/complicações , Encefalite Límbica/complicações , Olfato/fisiologia , Idoso , Eletroencefalografia , Epilepsia do Lobo Temporal/diagnóstico por imagem , Humanos , Encefalite Límbica/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Odorantes , Tomógrafos ComputadorizadosRESUMO
Among the existing elemental characterization techniques, particle-induced x-ray emission (PIXE) and energy-dispersive x-ray (EDX) spectroscopy are two of the most widely used in different scientific and technological fields. Here, we present the first quantitative laser-driven PIXE and laser-driven EDX experimental investigation performed at the Centro de Láseres Pulsados in Salamanca. Thanks to their potential for compactness and portability, laser-driven particle sources are very appealing for materials science applications, especially for materials analysis techniques. We demonstrate the possibility to exploit the x-ray signal produced by the co-irradiation with both electrons and protons to identify the elements in the sample. We show that, using the proton beam only, we can successfully obtain quantitative information about the sample structure through laser-driven PIXE analysis. These results pave the way toward the development of a compact and multifunctional apparatus for the elemental analysis of materials based on a laser-driven particle source.
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INTRODUCTION: Skeletal fragility with high risk of vertebral fractures is an emerging complication of acromegaly in close relationship with duration of active disease. The aim of this cross-sectional study was to evaluate the prevalence and determinants of vertebral fractures in males and females with a history of long-standing active acromegaly undergoing treatment with Pegvisomant. SUBJECTS AND METHODS: Thirty-eight patients (25 females, 13 males) with acromegaly under Pegvisomant therapy were evaluated for vertebral fractures and bone mineral density at lumbar spine and femoral neck. Gonadal status, serum IGF1 levels and growth hormone receptor genotype were also assessed. RESULTS: Vertebral fractures were detected in 12 patients (31.6%). Fractured patients had longer duration of active disease (p = 0.01) with higher frequency of active acromegaly (p = 0.04), received higher dose of Pegvisomant (p = 0.008), and were more frequently hypogonadic (p = 0.02) as compared to patients who did not fracture. Stratifying the patients for gender, vertebral fractures were significantly associated with Pegvisomant dose (p = 0.02) and untreated hypogonadism (p = 0.02) in males and with activity of disease (p = 0.03), serum insulin-like growth factor-I values (p = 0.01) and d3GHR polymorphism (p = 0.005) in females. No significant association was found between vertebral fractures and bone mineral density at either skeletal site. CONCLUSION: Vertebral fractures are a frequent complication of long-standing active acromegaly. When patients are treated with Pegvisomant, vertebral fractures may occur in close relationship with active acromegaly and coexistent untreated hypogonadism.
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Acromegalia/epidemiologia , Densidade Óssea/fisiologia , Fraturas da Coluna Vertebral/epidemiologia , Absorciometria de Fóton , Acromegalia/diagnóstico por imagem , Acromegalia/tratamento farmacológico , Adulto , Idoso , Estudos Transversais , Feminino , Colo do Fêmur/diagnóstico por imagem , Hormônio do Crescimento Humano/análogos & derivados , Hormônio do Crescimento Humano/uso terapêutico , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Prevalência , Fraturas da Coluna Vertebral/diagnóstico por imagemRESUMO
PURPOSE AND PATIENTS: The M.O.S.CA.TI. (Metastases of the Skeleton from CArcinoma of the ThyroId) is a multicenter, retrospective study investigating the real-life outcome and management of bone metastases (BM) in 143 patients (63 M, 80 F; median age 64 years, range 11-87) with differentiated thyroid carcinoma (DTC). RESULTS: Radio-active iodine (RAI) treatment was performed in 131 patients (91.6%), surgical approach and/or external radiotherapy in 68 patients (47.6%), and anti-resorptive bone-active drugs in 32 patients (22.4%; in 31 zoledronate and in one denosumab). At the start of treatment, 24 patients (75.0%) receiving anti-resorptive bone-active drugs had at least one clinical skeletal-related event (SRE) (p < 0.001). One or more clinical SREs (pathological fractures and/or malignant hypercalcemia and/or spinal cord compression) developed in 53 patients (37.1%). Development of SREs was significantly associated with metachronous BM (hazard ratio (HR) 2.04; p = 0.04), localization of BM to cervical spine (HR 3.89; p = 0.01), and lack of avid RAI uptake (HR 2.66; p = 0.02). Thirty-nine patients (27.3%) died in correlation with development of SREs (HR 6.97; p = 0.006) and localization of BM to the hip (HR 3.86; p = 0.02). Moreover, overall mortality was significantly decreased by RAI therapy (HR 0.10; p = 0.02), whereas no significant effects were induced by bone-active drugs (p = 0.36), external radiotherapy (p = 0.54), and surgery (p = 0.43) of BM. CONCLUSIONS: SREs are very frequent in BM from DTC and they impact patient survival. In the real life, the use of bone-active drugs is currently limited to zoledronate in patients with pre-existing SREs. In this clinical setting, RAI therapy, but not zoledronate, decreased mortality.
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Neoplasias Ósseas/secundário , Neoplasias Ósseas/terapia , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/terapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/epidemiologia , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/epidemiologia , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Glycogen storage diseases are inherited defects which cause accumulation of glycogen in the tissues. Hepatic steatosis is defined as accumulation of fat within hepatocytes. On sonography, liver shows increased echogenicity both in glycogen storage diseases and steatosis. Liver hyperechogenicity in glycogen storage diseases may depend on accumulation of glycogen and/or fat. Chemical-shift magnetic resonance imaging can discriminate tissues only containing water from those containing both fat and water. AIM: The primary aim of the present study was to evaluate the usefulness of liver chemical-shift magnetic resonance imaging for detecting liver steatosis in patients with metabolic impairment due to glycogen storage diseases. SUBJECTS: Twelve patients with type I (n=8) or type III (n=4) glycogen storage diseases were studied and compared to 12 obese-overweight subjects with known liver steatosis. As control group 12 lean normal voluntary subjects were recruited. METHODS: Liver was evaluated by sonography and chemical-shift magnetic resonance imaging to calculate hepatic fat fraction. RESULTS: A significant difference in echogenicity between patients with glycogen storage diseases and normal subjects was observed (p<0.05), while this difference was not present between overweight-obese and glycogen storage diseases patients. On the contrary, fat fraction was similar between glycogen storage diseases patients and normal subjects and different between glycogen storage diseases patients and overweight-obese (p<0.05). CONCLUSION: The present data suggest that chemical-shift magnetic resonance imaging may exclude fat deposition as a cause of liver hyperechogenicity in subjects with glycogen storage diseases.
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Fígado Gorduroso/complicações , Fígado Gorduroso/diagnóstico , Doença de Depósito de Glicogênio/complicações , Imageamento por Ressonância Magnética , Adolescente , Adulto , Criança , Fígado Gorduroso/diagnóstico por imagem , Feminino , Doença de Depósito de Glicogênio/metabolismo , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , UltrassonografiaRESUMO
The effects of long-term replacement therapy of adrenal insufficiency (AI) are still a matter of controversy. In fact, the established glucocorticoid replacement regimens do not completely reproduce the endogenous hormonal production and the monitoring of AI treatment may be a challenge for the lack of reliable clinical and biochemical markers. Consequently, several AI patients are frequently exposed to relative glucocorticoid excess potentially leading to develop chronic complications, such as diabetes mellitus, dyslipidemia, hypertension and fragility fractures with consequent impaired QoL and increased mortality risk. This review deals with the pathophysiological and clinical aspects concerning the over-replacement therapy of primary and secondary AI.
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Insuficiência Adrenal/diagnóstico , Insuficiência Adrenal/terapia , Gerenciamento Clínico , Uso Excessivo dos Serviços de Saúde/prevenção & controle , Insuficiência Adrenal/sangue , Terapia de Reposição Hormonal/efeitos adversos , Terapia de Reposição Hormonal/métodos , Humanos , Hidrocortisona/uso terapêutico , Fatores de RiscoRESUMO
BACKGROUND: Impulse Control Disorder symptoms (ICD) in Parkinson's disease (PD) has been recently associated by magnetic Resonance imaging with impaired cortico-striatal connectivity, especially between left putamen and frontal associative areas. METHODS: 84 patients entered the study (21 PD-ICD+ and 64 PD-ICD-) and underwent DATSCAN imaging. The striatal tracer uptake was evaluated using BRASS software (Hermes, Sweden). The whole-brain analysis was performed with Statistical Parametric Mapping (SPM). RESULTS: PD-ICD+ showed a significant reduction of left putaminal and left inferior frontal gyrus tracer uptake compared to PD-ICD-. Functional covariance analysis using left putamen as the seed point showed that, in contrast to ICD-patients, ICD+ patients had no functional covariance with contralateral basal ganglia and ipsilateral cingulate cortex, as index of an impaired inter- and intra-hemispheric dopamine binding in PD-ICD+. DISCUSSION: the results support and expand the concept of a functional disconnection syndrome linked to ICD symptoms in PD patients through an asymmetric molecular frontostriatal network breakdown with left basal ganglia as central hub.
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Corpo Estriado/fisiopatologia , Transtornos Disruptivos, de Controle do Impulso e da Conduta/complicações , Vias Neurais/fisiopatologia , Doença de Parkinson/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Mapeamento Encefálico/métodos , Corpo Estriado/patologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-IdadeRESUMO
Human red blood cells (RBC) can be studied by means of whole-cell and nystatin-perforated patch-clamp techniques. In 85% of the whole-cell experiments (n=86) and 69% of the perforated-patch recordings (n=13), steps to positive potentials, from a holding potential of 0 mV, induced a slow-activating non-inactivating persistent outward current which reverted at about 0 mV. The current activation phase fitted well with a two-component exponential curve. Half-maximal conductance was reached at about 42 mV. Na+ and K+ carried this current, which was not affected by 20 nM charybdotoxin or 20 mM TEA, but was reduced following a partial substitution of extracellular Cl- by tartrate. This current has characteristics similar to the single-channel currents already described in RBC and may be involved in the rapid adaptations of these cells in the circulation.
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Eritrócitos/química , Canais Iônicos/química , Cloretos/farmacologia , Humanos , Potenciais da Membrana , Nistatina , Técnicas de Patch-ClampRESUMO
AIMS: To evaluate the feasibility of ultra-low-dose CT for left atrium and pulmonary veins using new model-based iterative reconstruction (MBIR) algorithm. METHODS AND RESULTS: Two hundred patients scheduled for catheter ablation were randomized into two groups: Group 1 (100 patients, Multidetector row CT (MDCT) with MBIR, no ECG triggering, tube voltage and tube current of 100 kV and 60 mA, respectively) and Group 2 [100 patients, MDCT with adaptive statistical iterative reconstruction algorithm (ASIR), no ECG triggering, and kV and mA tailored on patient BMI]. Image quality, CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of left atrium (LA) and pulmonary veins, and effective dose (ED) were evaluated for each exam and compared between two groups.No significant differences between groups in terms of population characteristics, cardiovascular risk factors, anatomical features, prevalence of persistent atrial fibrillation and image quality score. Statistically significant differences were found between Group 1 and Group 2 in mean attenuation, SNR, and CNR of LA. Significantly, lower values of noise were found in Group 1 versus Group 2. Group 1 showed a significantly lower mean ED in comparison with Group 2 (0.41 ± 0.04 versus 4.17 ± 2.7 mSv). CONCLUSION: The CT for LA and pulmonary veins imaging using MBIR is feasible and allows examinations with very low-radiation exposure without loss of image quality.
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Fibrilação Atrial/diagnóstico por imagem , Átrios do Coração/diagnóstico por imagem , Veias Pulmonares/diagnóstico por imagem , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Fibrilação Atrial/cirurgia , Técnicas de Imagem de Sincronização Cardíaca , Meios de Contraste , Estudos de Viabilidade , Feminino , Humanos , Iopamidol/análogos & derivados , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Razão Sinal-Ruído , SoftwareRESUMO
Voltage-dependent Ca2+ channels in adult rat sensory neurones were studied as far as their characterization and nimodipine effects are concerned, using patch-clamp whole-cell technique. Low-voltage activated (LVA) Ca2+ currents were identified according to activation and inactivation kinetics and sensitivity to amiloride. Nimodipine (10 nM) caused a decrease in LVA Ca2+ current amplitude (-40% +/- 2.2 s.e.m., n = 11 out of 30 with LVA Ca2+ currents). Conversely, in 6 neurones out of 30 nimodipine increased the Ca2+ current amplitude (+ 10% +/- 2). In some unaffected neurones (n = 5) nimodipine was also tested at higher concentrations (up to 5 microM) without any appreciable effect. In conclusion, nimodipine was partly able to block LVA calcium channels even at nanomolar concentrations. Supposing nimodipine acts directly on the channel, it can be assumed that there may be different types of LVA calcium channels in sensory neurones.
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Canais de Cálcio/efeitos dos fármacos , Neurônios Aferentes/efeitos dos fármacos , Nimodipina/farmacologia , Animais , Cálcio/metabolismo , Canais de Cálcio/classificação , Células Cultivadas , Gânglios Espinais/citologia , Potenciais da Membrana , Neurônios Aferentes/fisiologia , Ratos , Ratos WistarRESUMO
Acetyl-L-carnitine produces a significant increase in the survival time-course of adult rat sensory neurons maintained in primary cultures up to 40 days. The analysis of our data suggests that 200 microM acetyl-L-carnitine added to the medium, slows down neuronal decay especially in the first 10 days in vitro, sparing a fraction of cells which would otherwise be lost. Patch-clamp recordings from these neurons show that superfusion with acetyl-L-carnitine (100-1000 microM) does not induce any membrane current. In addition an agonist muscarinic effect particularly concerning high-voltage activated calcium channel modulation appears to be ruled out. In conclusion our data favour the role of acetyl-L-carnitine in the trophism of sensory neurons in adult rats. In agreement with other in vivo experiments our data reinforce the hypothesis that this substance might be involved in reducing neuronal loss observed in nervous system aging.
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Acetilcarnitina/farmacologia , Gânglios Espinais/citologia , Neurônios Aferentes/citologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Condutividade Elétrica , Gânglios Espinais/fisiologia , Cinética , Potenciais da Membrana/efeitos dos fármacos , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/fisiologia , Ratos , Ratos Wistar , Tetrodotoxina/farmacologia , Fatores de TempoRESUMO
High- and low-voltage activated calcium channel currents (HVA and LVA) were inhibited by acetylcholine (10-100 microM) and baclofen (10 microM) in adult rat sensory neurons. This modulatory effect was present on dihydropyridine (nifedipine 1 microM) and/or omega-conotoxin (3.2 microM, 2-5 h incubation) insensitive components and was insensitive to holding potentials (Vh -50 to -90 mV). GTP-gamma-S (100 microM) prolonged calcium channel current activation in a time- and voltage-dependent manner. On the other hand, the current amplitude reduction induced by muscarinic and GABAB receptor activation, was not relieved by a 50-ms conditioning prepulse to +50 mV. This suggests the possibility of an alternative voltage-independent modulation mechanism.
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Acetilcolina/farmacologia , Baclofeno/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Guanosina 5'-O-(3-Tiotrifosfato)/farmacologia , Neurônios Aferentes/efeitos dos fármacos , ômega-Conotoxinas , Animais , Eletrofisiologia , Gânglios Espinais/citologia , Gânglios Espinais/efeitos dos fármacos , Ácido Homovanílico/metabolismo , Peptídeos Cíclicos/farmacologia , Ratos , Ratos EndogâmicosRESUMO
In unanaesthetized, undrugged, normally respiring cats extracellular recordings were obtained from ventroposterolateral thalamic units through different states of the sleep-waking cycle. An air-puff peripheral stimulation was used to activate the recorded neurones. State-dependent changes of the response of thalamic neurones were shown, comparing slow-wave sleep (SWS) to wakefulness (W). During SWS an increase was observed in the strength of the discharge suppression, which follows the excitatory peak in the typical response pattern. Also the cell excitability is further reduced in slow-wave sleep during the 150-200 ms period following an excitatory response, suggesting that an enhancement of the post-excitatory inhibition could be involved in the generation of the slow 5-6 Hz rhythms, observed during thalamic and cortical synchronization.