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1.
Phys Chem Chem Phys ; 20(23): 15907-15915, 2018 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-29850733

RESUMO

In this work, we investigate the optical properties of hafnium dioxide nanocrystals, upon X-ray irradiation, looking for spectral evolution following thermal treatments in air up to 1000 °C that modify the crystal size as well as their point defect concentrations. Radio-luminescence measurements from 10 K up to room temperature reveal a rich and evolving picture of the optical features. A complete spectral analysis of the broad luminescence spectra reveals the presence of several emission components in the visible and UV regions. The lower energy components peaking at 2.1, 2.5, and 2.9 eV are characterized by a thermal quenching energy of 0.08 eV, while the corresponding value for the UV bands at 4.1 and 4.7 eV is close to 0.23 eV. We tentatively assign the components ranging from 2 to 3 eV to the presence of optically active defects of an intrinsic nature, together with the occurrence of titanium impurities; conversely, the bands at higher energies are likely to be of an excitonic nature. The comparison with previous photo-luminescence studies allows evidencing characteristic differences between the features of luminescence emissions caused by intra-centre excitation and those occurring under ionizing irradiation. Finally, scintillation measurements in the visible range reveal the existence of a fast decay in the nanosecond time scale for the smallest hafnia nanocrystals. This study offers a clear description of HfO2 luminescence characteristics upon excitation by X-rays and can lead to a better comprehension of the structure-property relationship at the nanoscale in metal oxides.

2.
Diabetes Metab Res Rev ; 33(6)2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28371189

RESUMO

BACKGROUND: The aim of the study was to investigate the different B-cell responses after a glucagon stimulation test (GST) versus mixed meal tolerance test (MMTT). METHODS: We conducted GST and MMTT in 10 healthy people (aged 25-40 years) and measured C-peptide, gastric inhibitory peptide (GIP) and glucagon-like peptide-1 (GLP-1) at different time points after the administration of 1 mg i.v. glucagon for GST or a liquid mixed meal for MMTT. RESULTS: The GST stimulated C-peptide showed a mean increase of 147.1%, whereas the mean increase of MMTT stimulated C-peptide was 99.82% (Δincrease = 47.2%). Maximum C-peptide level reached with the MMTT was greater than that obtained with the GST (C-pept max MMTT = 2.35 nmol/L vs C-pep max GST = 1.9 nmol/L). A positive and linear correlation was found between the GST incremental area under the curve C-peptide and the MMTT incremental area under the curve C-peptide (r = 0.618, P = .05). After GST, there was no increment of GIP and glucagon like peptide-1 levels compared to baseline levels. A positive and linear correlation between GIP and C-peptide levels was observed only for the MMTT (r = 0.922, P = .008) indicating that in the GST, the C-peptide response is independent of the incretin axis response. CONCLUSIONS: Although the 2 stimulation tests may elicit a similar response in C-peptide secretion, B-cell response to MMTT depends on a functionally normal incretin axis. These results may have implications when investigating the B-cell response in people with diabetes and for studies in which stimulated C-peptide secretion is used as primary or secondary outcome for response to therapy.


Assuntos
Peptídeo C/metabolismo , Diabetes Mellitus Tipo 2/diagnóstico , Técnicas de Diagnóstico Endócrino , Polipeptídeo Inibidor Gástrico/farmacologia , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Glucagon/administração & dosagem , Células Secretoras de Insulina/efeitos dos fármacos , Refeições , Adulto , Estudos Cross-Over , Diabetes Mellitus Tipo 2/fisiopatologia , Ingestão de Alimentos/fisiologia , Feminino , Humanos , Células Secretoras de Insulina/fisiologia , Masculino , Estimulação Química
3.
Ann Ig ; 29(6): 481-493, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29048447

RESUMO

The Erice 50 Charter titled "Strategies for Diseases Prevention and Health Promotion in Urban Areas" was unanimously approved at the conclusion of the 50th Residential Course "Urban Health. Instruments for promoting health and for assessing hygienic and sanitary conditions in urban areas", held from 29th March to 2nd April 2017 in Erice, at the "Ettore Majorana" Foundation and Centre for Scientific Culture and promoted by the International School of Epidemiology and Preventive Medicine "G. D'Alessandro" and the Study Group "Building Hygiene" of the Italian Society of Hygiene, Preventive Medicine and Public Health (SItI). At the conclusion of the intense learning experience during the Course, with more than 20 lectures, workshops and long-lasting discussions between Professors and Students, the participants identified the major points connecting urban features and Public Health, claiming the pivotal role of urban planning strategies for the management of Diseases Prevention and Health Promotion activities. The Erice 50 Charter is configured as a Decalogue for Healthy Cities and as a Think Tank for designing effective strategic actions and best practices to develop urban regeneration interventions and improve the urban quality of contemporary cities. The Decalogue is structured into the following key strategic objectives: 1. Promoting urban planning interventions that address citizens towards healthy behaviours; 2. Improving living conditions in the urban context; 3. Building an accessible and inclusive city, with a special focus on the frail population; 4. Encouraging the foundation of resilient urban areas; 5. Supporting the development of new economies and employment through urban renewal interventions; 6. Tackling social inequalities; 7. Improving stakeholders' awareness of the factors affecting Public Health in the cities; 8. Ensuring a participated urban governance; 9. Introducing qualitative and quantitative performance tools, capable of measuring the city's attitude to promote healthy lifestyles and to monitor the population's health status; 10. Encouraging sharing of knowledge and accessibility to informations. Finally, all the participants underlined that a multidisciplinary team, composed of Physicians specialized in Hygiene, Preventive Medicine, Public Health and Technicians as Architects, Urban planners and Engineers, is needed to deepen the research topic of Urban Health.


Assuntos
Promoção da Saúde/métodos , Prevenção Primária/métodos , Saúde da População Urbana , Humanos , Itália
4.
Nutr Metab Cardiovasc Dis ; 26(7): 603-613, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27113292

RESUMO

BACKGROUND AND AIMS: Obesity is often associated with an increased cardiovascular risk. The food industry and the associated research activities focus on formulating products that are a perfect mix between an adequate fat content and health. We evaluated whether a diet enriched with Bio-Oil Spread (SD), an olive oil-based innovative food, is cardioprotective in the presence of high-fat diet (HFD)-dependent obesity. METHODS AND RESULTS: Rats were fed for 16 weeks with normolipidic diet (ND; fat: 6.2%), HFD (fat: 42%), and ND enriched with SD (6.2% of fat + 35.8% of SD). Metabolic and anthropometric parameters were measured. Heart and liver structures were analyzed by histochemical examination. Ischemic susceptibility was evaluated on isolated and Langendorff-perfused cardiac preparations. Signaling was assessed by Western blotting. Compared to ND rats, HFD rats showed increased body weight and abdominal obesity, dyslipidemia, and impaired glucose tolerance. Morphological analyses showed that HFD is associated with heart and liver modifications (hypertrophy and steatosis, respectively), lesser evident in the SD group, together with metabolic and anthropometric alterations. In particular, IGF-1R immunodetection revealed a reduction of hypertrophy in SD heart sections. Notably, SD diet significantly reduced myocardial susceptibility against ischemia/reperfusion (I/R) with respect to HFD through the activation of survival signals (Akt, ERK1/2, and Bcl2). Systolic and diastolic performance was preserved in the SD group. CONCLUSIONS: We suggest that SD may contribute to the prevention of metabolic disorders and cardiovascular alterations typical of severe obesity induced by an HFD, including the increased ischemic susceptibility of the myocardium. Our results pave the way to evaluate the introduction of SD in human alimentary guidelines as a strategy to reduce saturated fat intake.


Assuntos
Suplementos Nutricionais , Síndrome Metabólica/prevenção & controle , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Obesidade Abdominal/prevenção & controle , Azeite de Oliva/administração & dosagem , Gordura Abdominal/metabolismo , Gordura Abdominal/fisiopatologia , Adiposidade , Ração Animal , Animais , Apoptose , Biomarcadores/sangue , Glicemia/metabolismo , Dieta Hiperlipídica , Modelos Animais de Doenças , Dislipidemias/sangue , Dislipidemias/etiologia , Dislipidemias/prevenção & controle , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Intolerância à Glucose/sangue , Intolerância à Glucose/etiologia , Intolerância à Glucose/prevenção & controle , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/patologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Hipertrofia Ventricular Esquerda/prevenção & controle , Preparação de Coração Isolado , Lipídeos/sangue , Fígado/metabolismo , Fígado/patologia , Síndrome Metabólica/sangue , Síndrome Metabólica/etiologia , Síndrome Metabólica/fisiopatologia , Infarto do Miocárdio/sangue , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Traumatismo por Reperfusão Miocárdica/sangue , Traumatismo por Reperfusão Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Miocárdio/metabolismo , Miocárdio/patologia , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/patologia , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Obesidade Abdominal/sangue , Obesidade Abdominal/etiologia , Obesidade Abdominal/fisiopatologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos Sprague-Dawley , Receptor IGF Tipo 1/metabolismo , Transdução de Sinais , Função Ventricular Esquerda , Remodelação Ventricular
5.
Int J Neurosci ; 126(6): 526-530, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26000932

RESUMO

The functional His452Tyr polymorphism in the 5HT2A receptor has been described to be associated with verbal memory in healthy adults, with worse episodic memory performances in Tyr452 (T) carriers. The aim of our study was to investigate a possible effect of this polymorphism on memory performances in Alzheimer disease (AD). We enrolled 169 patients affected by probable AD. 5HT2A genotype was determined as previously described. According to their genotype, patients were divided in T carriers ( n = 111) and non-carriers ( n = 69). We evaluated the possible effect of 5HT2A polymorphism on verbal memory tasks. A one-way MANOVA analysis did not show a positive interaction between the two groups ( p > 0.05) at the baseline and at the follow-up. Nevertheless, the analyses of the single-task effect showed lower performances for non-T carriers only in Rey's recognition task. Recent data reported poorer memory performances in healthy subjects carrying the T variant, in age-dependent manner (no differences between T vs. nT carriers were observed for age >50 years). In our AD sample, we did not find significant differences in verbal memory scores in T vs. nT carriers while a significant difference was found only in attentional task. At variance with that in healthy subjects, no correlation has been found between memory profiles of AD patients and His452Tyr polymorphism.

6.
Phys Chem Chem Phys ; 17(7): 5141-50, 2015 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-25599651

RESUMO

Phase transformations at the nanoscale represent a challenging field of research, mainly in the case of nanocrystals (NCs) in a solid host, with size-effects and interactions with the matrix. Here we report the study of the structural evolution of γ-Ga2O3 NCs in alkali-germanosilicate glass - a technologically relevant system for its light emission and UV-to-visible conversion - showing an evolution drastically different from the expected transformation of γ-Ga2O3 into ß-Ga2O3. Differential scanning calorimetry registers an irreversible endothermic process at ∼1300 K, well above the exothermic peak of γ-Ga2O3 nano-crystallization (∼960 K) and below the melting temperature (∼1620 K). Transmission electron microscopy and X-ray diffraction data clarify that glass-embedded γ-Ga2O3 NCs transform into LiGa5O8via diffusion-driven kinetics of Li incorporation into NCs. At the endothermic peak, ß-Ga2O3 forms from LiGa5O8 dissociation, following a nucleation-limited kinetics promoted by size-dependent order-disorder change between LiGa5O8 polymorphs. As a result of the changes, modifications of UV-excited NC light emission are registered, with potential interest for applications.

7.
Diabetes Obes Metab ; 16(3): 262-7, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24118704

RESUMO

AIMS: C-peptide secretion is currently the only available clinical biomarker to measure residual ß-cell function in type 1 diabetes. However, the natural history of C-peptide decline after diagnosis can vary considerably dependent upon several variables. We investigated the shape of C-peptide decline over time from type 1 diabetes onset in relation to age at diagnosis, haemoglobin A1c (HbA1c) levels and insulin dose. METHODS: We analysed data from 3929 type 1 diabetes patients recruited from seven European centres representing all age groups at disease onset (childhood, adolescence and adulthood). The influence of the age at onset on ß-cell function was investigated in a longitudinal analysis at diagnosis and up to 5-years follow-up. RESULTS: Fasting C-peptide (FCP) data at diagnosis were available in 3668 patients stratified according to age at diagnosis in four groups (<5 years, n = 344; >5 years < 10 years, n = 668; >10 years < 18 years, n = 991; >18 years, n = 1655). FCP levels were positively correlated with age (p < 0.001); the subsequent decline in FCP over time was log-linear with a greater decline rate in younger age groups (p < 0.0001). CONCLUSIONS: This study reveals a positive correlation between age at diagnosis of type 1 diabetes and FCP with a more rapid decline of ß-cell function in the very young patients. These data can inform the design of clinical trials using C-peptide values as an end-point for the effect of a given treatment.


Assuntos
Envelhecimento , Peptídeo C/sangue , Diabetes Mellitus Tipo 1/metabolismo , Hipoglicemiantes/uso terapêutico , Anticorpos Anti-Insulina/sangue , Células Secretoras de Insulina/metabolismo , Insulina/uso terapêutico , Adolescente , Adulto , Fatores Etários , Idade de Início , Envelhecimento/metabolismo , Biomarcadores/sangue , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/tratamento farmacológico , Relação Dose-Resposta a Droga , Europa (Continente) , Jejum , Feminino , Seguimentos , Humanos , Estudos Longitudinais , Masculino
8.
Rhinology ; 50(4): 427-35, 2012 12.
Artigo em Inglês | MEDLINE | ID: mdl-23193535

RESUMO

BACKGROUND: Glucocorticoids (GCs) are considered drugs of choice for treating nasal polyps (NPs). However, a subset of patients shows a limited clinical response even to high doses of GCs. Altered expression of glucocorticoid receptors (GRs), namely GR-alpha; and GR-beta;, is a potential mechanism underlying GC insensitivity. GCs modulate the expression of several cytokines, including transforming growth factor-beta (TGF-beta), which may contribute to cellular proliferation in NPs. The study investigates some biomolecular features of GC-resistant NPs, and examines possible differences from normal mucosa (NM). METHODOLOGY: Radioligand binding assay (binding) was used to determine GR-alpha; binding capacity; Western blotting was used to evaluate GR-alpha;, GR-beta;, and TGF-beta; expression and GR-alpha; subcellular distribution. NPs were sampled in 32 patients during ethmoidectomy; NM was taken from 15 healthy patients during rhinoplasty. RESULTS: GR-alpha; was present in NPs and NM, with lower affinity for the ligand in NPs. GR-alpha; was prevalent in the cytosol of NPs that were GR-alpha-negative to the binding assay. GR-beta was expressed in NPs and absent in the majority of NM. TGF-beta1 expression was higher in NPs than in NM. CONCLUSIONS: GR-beta and TGF-beta1 might be involved in NP pathogenesis, but their role in modulating GC sensitivity is still unclear.


Assuntos
Pólipos Nasais/fisiopatologia , Receptores de Glucocorticoides/fisiologia , Fator de Crescimento Transformador beta1/fisiologia , Resistência a Medicamentos , Eletroforese em Gel de Poliacrilamida , Endoscopia , Feminino , Glucocorticoides/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Pólipos Nasais/tratamento farmacológico , Pólipos Nasais/cirurgia , Prednisona/uso terapêutico
9.
Diabetes Obes Metab ; 13(1): 42-6, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21114602

RESUMO

AIM: Postprandial hyperglycaemia is a consequence of reduced first phase insulin response and is associated with increased cardiovascular risk and mortality. The aim of this proof-of-concept study was to investigate the safety and efficacy of treatment with buccal spray insulin (Oral-lyn™, Generex Biotechnology Corporation, Toronto, Ontario, Canada) on postprandial plasma glucose and insulin levels in subjects with impaired glucose tolerance (IGT). METHODS: A total of 19 female and 12 male Caucasian subjects, 52.2 ± 13.5 (SD) years old, having a body mass index of 33.1 ± 6 (SD) kg/m² with confirmed IGT were included in the study. Subjects were randomized to take 4, 6 or 12 Oral-lyn puffs (1 puff = 1 s.c. rapid insulin UI) split into two equal doses each, one before and the second 30 min after a standard 75 g oral glucose tolerance test (OGTT). Glucose and insulin levels were measured at baseline and 30, 60, 90, 120 and 180 min afterwards. RESULTS: Glucose fluctuations during OGTT were not modified by 4 or 6 Oral-lyn puffs. Treatment with 12 puffs was followed by 29.6% decrease in plasma glucose at 2 h and 26.8% decrease at 3 h, altogether p = 0.01. Considering all time points of the OGTT, there was a mean reduction of 15.8% in glucose levels. With 6 of the total 12 puffs used in group C there was a significant increase in the insulin levels during OGTT at 30 min (p < 0.04) but not at 2 or 3 h. No hypoglycaemic episodes were observed at any time points of the OGTT. CONCLUSIONS: This proof-of-concept study demonstrates that treatment with buccal spray insulin is a simple and valuable therapy for reducing postprandial hyperglycaemia in obese subjects with IGT. Importantly, this treatment is safe and none of the study subjects experienced hypoglycaemia.


Assuntos
Intolerância à Glucose/tratamento farmacológico , Hiperglicemia/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Período Pós-Prandial/efeitos dos fármacos , Administração Bucal , Canadá , Feminino , Humanos , Hiperglicemia/prevenção & controle , Hipoglicemiantes/farmacocinética , Insulina/farmacocinética , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
10.
G Ital Med Lav Ergon ; 33(3 Suppl): 108-11, 2011.
Artigo em Italiano | MEDLINE | ID: mdl-23393815

RESUMO

Clinical and biological prognostic factors in 135 patients affected by sinonasal carcinoma treated in Piedmont. Long-term survival of patients with sinonasal carcinoma remains disappointing in spite of aggressive treatment. The aim of the study is the assessment of overall survival in a group of patients treated with a fixed protocol and the positivity of proliferation and neoangiogenesis markers (Ki-67 and VEGF). From our data it comes out that staging, histological type and treatment are the most important clinical and pathological prognostic factors, moreover surgery +/- radiotherapy is the first line treatment for these tumors. Proliferation index and neoangiogenesis plays a pivotal role in the natural history of such neoplasms.


Assuntos
Carcinoma de Células Escamosas/mortalidade , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias dos Seios Paranasais/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/terapia , Feminino , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Neoplasias dos Seios Paranasais/terapia , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço , Taxa de Sobrevida , Adulto Jovem
11.
J Neural Transm (Vienna) ; 117(3): 377-83, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20058037

RESUMO

Alzheimer's disease (AD) is characterized by a significant reduction in AcetylCholinesterase and an increase in ButyrylCholinesterase (BuChE) activity. The existence of polymorphic regions on the BuChE gene has been previously described; the most frequently found polymorphism is the so-called K variant, which leads to a 30% decreased enzymatic activity. Different studies reported a positive association between K variant and AD, strongest among late-onset AD and Apolipoprotein E (APOE) e4 carriers. We analyzed APOE and BuChE polymorphisms in 167 AD and 59 fronto-temporal dementia (FTD) patients compared with 129 healthy controls (HC). We reported a significantly lower frequency of the BuChE K variant in AD compared with HC and FTD and a significant increased frequency of the K variant in FTD. These results are in agreement with the known increase of the BuChE activity in AD and support the evidence of different molecular pathways involved in the pathogenesis of AD and FTD.


Assuntos
Doença de Alzheimer/enzimologia , Butirilcolinesterase/metabolismo , Demência Frontotemporal/enzimologia , Idoso , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Apolipoproteína E4/metabolismo , Butirilcolinesterase/genética , Feminino , Demência Frontotemporal/genética , Demência Frontotemporal/metabolismo , Frequência do Gene , Genótipo , Humanos , Isoenzimas/metabolismo , Masculino , Polimorfismo Genético
12.
Eur J Neurol ; 15(2): 173-8, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18217885

RESUMO

Codon 129 polymorphism of the prion protein gene represents a major genetic risk factor for Creutzfeldt-Jakob disease (CJD). Both CJD and Alzheimer's disease (AD) are brain amyloidoses and it would be possible that codon 129 polymorphism plays a role in the susceptibility to AD. In order to investigate this polymorphism in AD the distribution of polymorphic codon 129 of the PRNP gene in 194 probable AD and 124 controls selected in Italy and 109 neuropathologically verified AD and 58 matched controls recruited in the USA was studied. No significant association was found for the PRNP polymorphism in AD compared to controls either in Probable or in Definite AD series even after stratification for APOE polymorphism. This study does not support a role of PRNP polymorphism as a susceptibility factor for AD.


Assuntos
Doença de Alzheimer/genética , Códon , Polimorfismo Genético , Príons/genética , Idoso , Idoso de 80 Anos ou mais , Apolipoproteínas E/genética , Feminino , Predisposição Genética para Doença , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Proteínas Priônicas , Estados Unidos
13.
J Biomol Struct Dyn ; 26(1): 115-30, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18533732

RESUMO

We have computationally studied the intercalation of the antitumor drug daunomycin into six stacks of Watson-Crick DNA base pairs (i.e., AT-AT, AT-TA, GC-AT, CG-TA, GC-GC, GC-CG) using density functional theory (DFT). The proton affinity of the DNA intercalator daunomycin in water was computed to be 159.2 kcal/mol at BP86/TZ2P, which is in line with the experimental observation that daunomycin is protonated under physiological conditions. The intercalation interaction of protonated daunomycin with two stacked DNA base pairs was studied through a hybrid approach in which intercalation is treated at LDA/TZP while the molecular structure of daunomycin and hydrogen-bonded Watson-Crick pairs is computed at BP86/TZ2P. We find that the affinity of the drug for the six considered base pair dimers decreases in the order AT-AT > AT-TA > GC-AT > GC-TA > GC-CG > GC-GC, in excellent agreement with experimental data on the thermodynamics of the interaction between daunomycin and synthetic polynucleotides in aqueous solution. Our analyses show that the overall stability of the intercalation complexes comes mainly from pi-pi stacking but an important contribution to the computed and experimentally observed sequence specificity comes from hydrogen bonding between daunomycin and hetero atoms in the minor groove of AT base pairs.


Assuntos
Antibióticos Antineoplásicos/metabolismo , DNA/química , DNA/metabolismo , Daunorrubicina/metabolismo , Substâncias Intercalantes/metabolismo , Antibióticos Antineoplásicos/química , Pareamento de Bases , Daunorrubicina/química , Ligação de Hidrogênio , Substâncias Intercalantes/química , Modelos Químicos , Modelos Moleculares , Conformação de Ácido Nucleico , Termodinâmica , Água/química
14.
Phys Med Biol ; 53(21): 6227-43, 2008 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-18923198

RESUMO

We report on tests of a room-temperature particle counting silicon pixel detector of the Medipix2 series as the detector unit of a positron autoradiography (AR) system, for samples labelled with (18)F-FDG radiopharmaceutical used in PET studies. The silicon detector (1.98 cm(2) sensitive area, 300 microm thick) has high intrinsic resolution (55 microm pitch) and works by counting all hits in a pixel above a certain energy threshold. The present work extends the detector characterization with (18)F-FDG of a previous paper. We analysed the system's linearity, dynamic range, sensitivity, background count rate, noise, and its imaging performance on biological samples. Tests have been performed in the laboratory with (18)F-FDG drops (37-37 000 Bq initial activity) and ex vivo in a rat injected with 88.8 MBq of (18)F-FDG. Particles interacting in the detector volume produced a hit in a cluster of pixels whose mean size was 4.3 pixels/event at 11 keV threshold and 2.2 pixels/event at 37 keV threshold. Results show a sensitivity for beta(+) of 0.377 cps Bq(-1), a dynamic range of at least five orders of magnitude and a lower detection limit of 0.0015 Bq mm(-2). Real-time (18)F-FDG positron AR images have been obtained in 500-1000 s exposure time of thin (10-20 microm) slices of a rat brain and compared with 20 h film autoradiography of adjacent slices. The analysis of the image contrast and signal-to-noise ratio in a rat brain slice indicated that Poisson noise-limited imaging can be approached in short (e.g. 100 s) exposures, with approximately 100 Bq slice activity, and that the silicon pixel detector produced a higher image quality than film-based AR.


Assuntos
Autorradiografia/instrumentação , Elétrons , Fluordesoxiglucose F18 , Silício , Animais , Encéfalo/citologia , Análise por Conglomerados , Modelos Lineares , Masculino , Ratos , Sensibilidade e Especificidade , Software
15.
Minerva Endocrinol ; 32(4): 275-95, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18091664

RESUMO

Osteoporosis and fractures associated with it constitute a real and serious socio-medical problem, which only recently has come to the forefront of social consciousness. The authors are carrying out a critical re-examination of the medical literature of osteoporosis pharmacological treatment. Particular attention has been paid to studies which show a clear reduction of the primary endpoint that, in the case of this pathology, consists of a reduction of the fracturing event. According to the examination of the clinical studies introduced, antiresorptive bone agents, such as alendronate and risenderonate, turn out to be molecules with higher levels of evidence implicated on the reduction of the main osteoporotic fractures, in particular the reduction of vertebral and femoral fractures. The 10 years long-term extension studies, in particular those that have seen the employment of alendronate, found a positive outcome regarding densitometry data and a favorable trend in antifracture effectiveness. Ibandronate is another amino-bisphosphonate which was recently validated as an effective drug for the treatment of osteoporosis with its documented ability to meaningfully reduce vertebral fractures. Also ranelate of strontium, a drug that seems to explain its own result in a different way from the other antiresorptive bone agents, constitutes another valid alternative in the treatment of this pathology. Both of these molecules however, need further studies in order to estimate their antifracture effectiveness in the long term, particularly those related to femoral fractures. Teriparatide and the entire molecule paratohormone are usually not prescribed for its high cost in treatment and because, typically, patients with high-risk level fractures that are already affected, produce more vertebral fractures from moderate to severe intensity.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Fraturas Ósseas/etiologia , Fraturas Ósseas/prevenção & controle , Osteoporose Pós-Menopausa/complicações , Alendronato/uso terapêutico , Reabsorção Óssea/prevenção & controle , Calcitonina/uso terapêutico , Ácido Clodrônico/uso terapêutico , Difosfonatos/uso terapêutico , Ácido Etidrônico/análogos & derivados , Ácido Etidrônico/uso terapêutico , Medicina Baseada em Evidências , Feminino , Humanos , Ácido Ibandrônico , Compostos Organometálicos/uso terapêutico , Ácido Risedrônico , Moduladores Seletivos de Receptor Estrogênico/uso terapêutico , Teriparatida/uso terapêutico , Tiofenos/uso terapêutico , Vitamina D/uso terapêutico
16.
Med Phys ; 33(8): 3066-75, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16964885

RESUMO

Mass localization plays a crucial role in computer-aided detection (CAD) systems for the classification of suspicious regions in mammograms. In this article we present a completely automated classification system for the detection of masses in digitized mammographic images. The tool system we discuss consists in three processing levels: (a) Image segmentation for the localization of regions of interest (ROIs). This step relies on an iterative dynamical threshold algorithm able to select iso-intensity closed contours around gray level maxima of the mammogram. (b) ROI characterization by means of textural features computed from the gray tone spatial dependence matrix (GTSDM), containing second-order spatial statistics information on the pixel gray level intensity. As the images under study were recorded in different centers and with different machine settings, eight GTSDM features were selected so as to be invariant under monotonic transformation. In this way, the images do not need to be normalized, as the adopted features depend on the texture only, rather than on the gray tone levels, too. (c) ROI classification by means of a neural network, with supervision provided by the radiologist's diagnosis. The CAD system was evaluated on a large database of 3369 mammographic images [2307 negative, 1062 pathological (or positive), containing at least one confirmed mass, as diagnosed by an expert radiologist]. To assess the performance of the system, receiver operating characteristic (ROC) and free-response ROC analysis were employed. The area under the ROC curve was found to be Az = 0.783 +/- 0.008 for the ROI-based classification. When evaluating the accuracy of the CAD against the radiologist-drawn boundaries, 4.23 false positives per image are found at 80% of mass sensitivity.


Assuntos
Inteligência Artificial , Neoplasias da Mama/diagnóstico por imagem , Armazenamento e Recuperação da Informação/métodos , Mamografia/métodos , Reconhecimento Automatizado de Padrão/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Sistemas de Informação em Radiologia , Algoritmos , Análise por Conglomerados , Sistemas de Gerenciamento de Base de Dados , Bases de Dados Factuais , Feminino , Humanos , Intensificação de Imagem Radiográfica/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Eur J Radiol ; 55(2): 264-9, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16036158

RESUMO

OBJECTIVE: The aim of the present study was to evaluate the efficacy of two different computer aided detection (CAD) systems for mammography in improving radiological diagnosis in the search of microcalcification clusters. The CAD systems used are: the SecondLooktrade mark (CADx Medical Systems, Canada) commercial system and the CALMA (computer assisted library in MAmmography) research CAD system. Three radiologists were asked to read mammographic images with and without the support of the CAD systems. MATERIAL AND METHODS: Three radiologists with respectively 3, 5 and 7 years of practice in mammogram reading in an Italian public hospital analysed a dataset composed of 120 digitized mammograms of healthy subjects with no lesion (proven by a radiological follow up of at least 3 years) and 70 images of patients with malignant cluster of microcalcification (proven by histopathological examination) both with no CAD support as well as with the help of the SecondLooktrade mark system. After 3 months they were asked to observe the same digitized mammograms with the assistance of the CALMA system. The radiologists worked independently and were unaware of the final diagnosis. The values of the area A(z) under the ROC curve, diagnostic sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were evaluated with and without the support of the CAD systems. The reading time and qualitative evaluations of each radiologist were also reported. RESULTS: With the support of the two CAD systems an improvement in A(z) area was obtained ranging from 0.01 to 0.04. Sensitivity increased from +8.6 to +15.7% and specificity decreased from 0.8 to 4.2%. CONCLUSION: In our study, not conditioned by the dataset, the CAD systems as second reader produced an increase in overall sensitivity of up to 15.7%, with a little decrease in specificity of up to 4.2%. Based on these results both CAD systems might be used in the current practise to improve the sensitivity values of conventional reading (radiologist alone). The results of this study show that no significant differences exist in term of A(z), sensitivity and specificity between CALMA and CADx.


Assuntos
Doenças Mamárias/diagnóstico por imagem , Mamografia/instrumentação , Calcinose/diagnóstico por imagem , Diagnóstico por Computador , Feminino , Humanos , Valor Preditivo dos Testes , Curva ROC , Interpretação de Imagem Radiográfica Assistida por Computador , Sensibilidade e Especificidade , Software
18.
Methods Inf Med ; 44(2): 244-8, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15924184

RESUMO

OBJECTIVES: The next generation of high energy physics (HEP) experiments requires a GRID approach to a distributed computing system: the key concept is the Virtual ORGANISATION (VO), a group of distributed users with a common goal and the will to share their resources. METHODS: A similar approach, applied to a group of hospitals that joined the GPCALMA project (Grid Platform for Computer Assisted Library for MAmmography), will allow common screening programs for early diagnosis of breast and, in the future, lung cancer. The application code makes use of neural networks for the image analysis and is useful in improving the radiologists' diagnostic performance. GRID services allow remote image analysis and interactive online diagnosis, with a potential for a relevant reduction of the delays presently associated with screening programs. RESULTS AND CONCLUSIONS: A prototype of the system, based on AliEn GRID Services [1], is already available, with a central server running common services [2] and several clients connecting to it. Mammograms can be acquired in any location; the related information required to select and access them at any time is stored in a common service called Data Catalogue, which can be queried by any client. Thanks to the PROOF facility [3], the result of a query can be used as input for analysis algorithms, which are executed on the nodes where the input images are stored,. The selected approach avoids data transfers for all the images with a negative diagnosis and allows an almost real time diagnosis for the set of images with high cancer probability.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Internet/instrumentação , Mamografia , Sistemas de Informação em Radiologia/instrumentação , Integração de Sistemas , Telerradiologia/instrumentação , Algoritmos , Sistemas de Gerenciamento de Base de Dados , Bases de Dados Factuais , Diagnóstico por Computador , Europa (Continente) , Feminino , Humanos , Internacionalidade , Itália , Sistemas Computadorizados de Registros Médicos , Desenvolvimento de Programas , Interface Usuário-Computador
19.
Eur J Endocrinol ; 172(2): 107-13, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25378371

RESUMO

OBJECTIVE: Body weight-related insulin resistance probably plays a role in progression to type 1 diabetes, but has an uncertain impact following diagnosis. In this study, we investigated whether BMI measured at diagnosis was an independent predictor of C-peptide decline 1-year post-diagnosis. DESIGN: Multicentre longitudinal study carried out at diagnosis and up to 1-year follow-up. METHODS: Data on C-peptide were collected from seven diabetes centres in Europe. Patients were grouped according to age at diagnosis (<5 years, n=126; >5 years <10 years, n=295; >10 years <18 years, n=421; >18 years, n=410). Linear regression was used to investigate whether BMI was an independent predictor of change in fasting C-peptide over 1 year. Models were additionally adjusted for baseline insulin dose and HbA1c. RESULTS: In individuals diagnosed between 0 and 5 years, 5 and 10 years and those diagnosed >18 years, we found no association between BMI and C-peptide decline. In patients aged 10-18 years, higher BMI at baseline was associated with a greater decline in fasting C-peptide over 1 year with a decrease (ß 95% CI; P value) of 0.025 (0.010, 0.041) nM/kg per m(2) higher baseline BMI (P=0.001). This association remained significant after adjusting for gender and differences in HbA1c and insulin dose (ß=0.026, 95% CI=0.0097, 0.042; P=0.002). CONCLUSIONS: These observations indicate that increased body weight and increased insulin demand are associated with more rapid disease progression after diagnosis of type 1 diabetes in an age group 10-18 years. This should be considered in studies of ß-cell function in type 1 diabetes.


Assuntos
Índice de Massa Corporal , Peptídeo C/sangue , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/diagnóstico , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Adolescente , Biomarcadores/sangue , Contagem de Células/métodos , Criança , Estudos de Coortes , Feminino , Humanos , Estudos Longitudinais , Masculino
20.
J Med Chem ; 42(14): 2561-8, 1999 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-10411476

RESUMO

Derivatives of the new ring system indolo[1,2-c]benzo[1,2,3]triazine 5 were synthesized by diazotization of substituted 2-(2-aminophenyl)indoles followed by an intramolecular coupling reaction of the diazonium group with the indole nitrogen. To obtain the indolobenzotriazine system it was necessary to protect the 3 position of the indole nucleus to avoid cyclization into the indolo[3,2-c]cinnoline system 4. Indolobenzotriazines 5a-g were evaluated in vitro for antitumor activity against a panel of leukemia-, lymphoma-, carcinoma-, and neuroblastoma-derived cell lines. Some compounds inhibited the proliferation of T and B cell lines at submicromolar concentrations, whereas their activity against solid tumor cell lines was in the micromolar range. When evaluated for their antifungal potential 5a,d inhibited some of the fungi tested, although at concentrations very close to those inhibiting the proliferation of human cells. On the contrary, all indolobenzotriazines proved fairly potent and selective inhibitors of Streptococcus and Staphylococcus. In particular 5b,c,g were up to 80 times more potent than the reference drug streptomycin and inhibited the growth of the above Gram-positive bacteria at concentrations far lower than those cytotoxic for animal cells.


Assuntos
Anti-Infecciosos/síntese química , Antineoplásicos/síntese química , Triazinas/síntese química , Antibacterianos , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Avaliação Pré-Clínica de Medicamentos , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , HIV-1 , Humanos , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade , Triazinas/química , Triazinas/farmacologia , Células Tumorais Cultivadas
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