Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 72
Filtrar
1.
Phys Med ; 119: 103300, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38325222

RESUMO

PURPOSE: The aim of the present study, conducted by a working group of the Italian Association of Medical Physics (AIFM), was to define typical z-resolution values for different digital breast tomosynthesis (DBT) models to be used as a reference for quality control (QC). Currently, there are no typical values published in internationally agreed QC protocols. METHODS: To characterize the z-resolution of the DBT models, the full width at half maximum (FWHM) of the artifact spread function (ASF), a technical parameter that quantifies the signal intensity of a detail along reconstructed planes, was analyzed. Five different commercial phantoms, CIRS Model 011, CIRS Model 015, Modular DBT phantom, Pixmam 3-D, and Tomophan, were evaluated on reconstructed DBT images and 82 DBT systems (6 vendors, 9 models) in use at 39 centers in Italy were involved. RESULTS: The ASF was found to be dependent on the detail size, the DBT angular acquisition range, the reconstruction algorithm and applied image processing. In particular, a progressively greater signal spread was observed as the detail size increased and the acquisition angle decreased. However, a clear correlation between signal spread and angular range width was not observed due to the different signal reconstruction and image processing strategies implemented in the algorithms developed by the vendors studied. CONCLUSIONS: The analysis led to the identification of typical z-resolution values for different DBT model-phantom configurations that could be used as a reference during a QC program.


Assuntos
Processamento de Imagem Assistida por Computador , Mamografia , Mamografia/métodos , Processamento de Imagem Assistida por Computador/métodos , Imagens de Fantasmas , Artefatos , Algoritmos
2.
ESMO Open ; 7(6): 100591, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36208496

RESUMO

BACKGROUND: A growing body of evidence suggests that non-viral hepatocellular carcinoma (HCC) might benefit less from immunotherapy. MATERIALS AND METHODS: We carried out a retrospective analysis of prospectively collected data from consecutive patients with non-viral advanced HCC, treated with atezolizumab plus bevacizumab, lenvatinib, or sorafenib, in 36 centers in 4 countries (Italy, Japan, Republic of Korea, and UK). The primary endpoint was overall survival (OS) with atezolizumab plus bevacizumab versus lenvatinib. Secondary endpoints were progression-free survival (PFS) with atezolizumab plus bevacizumab versus lenvatinib, and OS and PFS with atezolizumab plus bevacizumab versus sorafenib. For the primary and secondary endpoints, we carried out the analysis on the whole population first, and then we divided the cohort into two groups: non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) population and non-NAFLD/NASH population. RESULTS: One hundred and ninety patients received atezolizumab plus bevacizumab, 569 patients received lenvatinib, and 210 patients received sorafenib. In the whole population, multivariate analysis showed that treatment with lenvatinib was associated with a longer OS [hazard ratio (HR) 0.65; 95% confidence interval (CI) 0.44-0.95; P = 0.0268] and PFS (HR 0.67; 95% CI 0.51-0.86; P = 0.002) compared to atezolizumab plus bevacizumab. In the NAFLD/NASH population, multivariate analysis confirmed that lenvatinib treatment was associated with a longer OS (HR 0.46; 95% CI 0.26-0.84; P = 0.0110) and PFS (HR 0.55; 95% CI 0.38-0.82; P = 0.031) compared to atezolizumab plus bevacizumab. In the subgroup of non-NAFLD/NASH patients, no difference in OS or PFS was observed between patients treated with lenvatinib and those treated with atezolizumab plus bevacizumab. All these results were confirmed following propensity score matching analysis. By comparing patients receiving atezolizumab plus bevacizumab versus sorafenib, no statistically significant difference in survival was observed. CONCLUSIONS: The present analysis conducted on a large number of advanced non-viral HCC patients showed for the first time that treatment with lenvatinib is associated with a significant survival benefit compared to atezolizumab plus bevacizumab, in particular in patients with NAFLD/NASH-related HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Hepatopatia Gordurosa não Alcoólica , Humanos , Sorafenibe/farmacologia , Sorafenibe/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Bevacizumab/farmacologia , Bevacizumab/uso terapêutico , Pontuação de Propensão , Estudos Retrospectivos , Neoplasias Hepáticas/tratamento farmacológico
4.
Sci Rep ; 11(1): 9095, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33907207

RESUMO

People communicate using speech, gestures, and, less frequently, touches. An example of tactile communication is represented by handshake. Customs surrounding handshake vary in different cultures. In Western societies is mostly used when meeting, parting, as a sign of congratulations or at the end of a successful business. Despite its importance in social life, the neural mechanism underlying the affective components conveyed by handshake ("tactile vitality forms") is unknown. Here we combined functional magnetic resonance imaging (fMRI) and electromyography (EMG), to investigate the neural affective activations during handshakes. We demonstrated that handshake conveying gentle or aggressive tactile vitality forms produces a stronger activation of the dorso-central insula. The simultaneous presence of emotional facial expressions modulates the activation of this insular sector. Finally, we provide evidence that the cingulate cortex is involved in the processing of facial expressions conveying different vitality forms.

6.
Radiat Prot Dosimetry ; 189(2): 224-233, 2020 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-32161966

RESUMO

We investigated the performances of two computed tomography (CT) systems produced by the same manufacturers (Somatom Flash and Edge Siemens) with different detector technologies (Ultrafast Ceramic and Stellar) and different generation of iterative reconstruction (IR) algorithms (SAFIRE and ADMIRE). A homemade phantom was scanned and the images were reconstructed with filtered back-projection (FBP) and IR algorithms. In terms of image quality, the performances of the systems were checked using the low-contrast detectability, evaluated by a Channelized Hotelling Observer (CHO), and the noise power spectrum (NPS). The analysis with CHO showed the best performance of Edge respect to Flash system for both FBP and IR algorithms. This better behavior, which reaches 20%, has been ascribed to the Stellar detector. From the NPS analysis, the noise reduction due to Stellar detector was 57%, moreover ADMIRE algorithm preserves a more traditional CT image texture appearance versus SAFIRE due to a lower NPS peak shift.


Assuntos
Algoritmos , Tomografia Computadorizada por Raios X , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador , Tomógrafos Computadorizados
7.
Br J Cancer ; 112(10): 1675-86, 2015 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-25880005

RESUMO

BACKGROUND: Despite the recognised contribution of the stroma to breast cancer development and progression, the effective targeting of the tumor microenvironment remains a challenge to be addressed. We previously reported that normal fibroblasts (NFs) and, notably, breast cancer-associated fibroblasts (CAFs) induced epithelial-to-mesenchymal transition and increases in cell membrane fluidity and migration in well- (MCF-7) and poorly-differentiated (MDA-MB-231) breast cancer cells. This study was designed to better define the role played, especially by CAFs, in promoting breast tumor cell migration. METHODS: Fibroblast/breast cancer cell co-cultures were set up to investigate the influence of NFs and CAFs on gene and protein expression of Stearoyl-CoA desaturase 1 (SCD1), the main enzyme regulating membrane fluidity, as well as on the protein level and activity of its transcription factor, the sterol regulatory element-binding protein 1 (SREBP1), in MCF-7 and MDA-MB-231 cells. To assess the role of SREBP1 in the regulation of SCD1 expression, the desaturase levels were also determined in tumor cells treated with an SREBP1 inhibitor. Migration was evaluated by wound-healing assay in SCD1-inhibited (by small-interfering RNA (siRNA) or pharmacologically) cancer cells and the effect of CAF-conditioned medium was also assessed. To define the role of stroma-derived signals in cancer cell migration speed, cell-tracking analysis was performed in the presence of neutralising antibodies to hepatocyte growth factor, transforming growth factor-ß or basic fibroblast growth factor. RESULTS: A two to three fold increase in SCD1 mRNA and protein expression has been induced, particularly by CAFs, in the two cancer cell lines that appear to be dependent on SREBP1 activity in MCF-7 but not in MDA-MB-231 cells. Both siRNA-mediated and pharmacological inhibition of SCD1 impaired tumor cells migration, also when promoted by CAF-released soluble factors. Fibroblast-triggered increase in cancer cell migration speed was markedly reduced or abolished by neutralising the above growth factors. CONCLUSION: These results provide further insights in understanding the role of CAFs in promoting tumor cell migration, which may help to design new stroma-based therapeutic strategies.


Assuntos
Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Movimento Celular/genética , Fibroblastos/patologia , Comunicação Parácrina/genética , Estearoil-CoA Dessaturase/genética , Neoplasias da Mama/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , Membrana Celular/genética , Técnicas de Cocultura/métodos , Transição Epitelial-Mesenquimal/genética , Feminino , Fatores de Crescimento de Fibroblastos/genética , Fator de Crescimento de Hepatócito/genética , Humanos , Células MCF-7 , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Fator de Crescimento Transformador beta/genética
8.
J Pediatr Urol ; 8(1): e7-9, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21907003

RESUMO

Leydig-cell tumours of the testis are rare and usually benign in children. The possibility of metachronous bilateral tumours should be considered not only for testicular teratomas but also in the follow up of a Leydig-cell tumour. Testis-sparing surgery is feasible and safe in prepubertal boys after exclusion of a malignant tumour.


Assuntos
Tumor de Células de Leydig/patologia , Segunda Neoplasia Primária/patologia , Neoplasias Testiculares/patologia , Biópsia por Agulha , Criança , Seguimentos , Humanos , Imuno-Histoquímica , Tumor de Células de Leydig/diagnóstico por imagem , Tumor de Células de Leydig/cirurgia , Masculino , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Estadiamento de Neoplasias , Segunda Neoplasia Primária/diagnóstico por imagem , Segunda Neoplasia Primária/cirurgia , Orquiectomia/métodos , Neoplasias Testiculares/diagnóstico por imagem , Neoplasias Testiculares/cirurgia , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia Doppler
9.
Int J Pediatr ; 2010: 951270, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20981247

RESUMO

We report a four-year-old boy with a nevus covering all the plantar side of his second finger on the left foot. He was also affected by congenital phimosis. Surgical excision of the nevus was indicated, but the skin defect would have been too large to be directly closed. The foreskin was taken as a full-thickness skin graft to cover the cutaneous defect of the finger. The graft intake was favourable and provided a functional repair with good aesthetic characteristic.

10.
Cephalalgia ; 28(10): 1012-6, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18727650

RESUMO

Tolerability is an important attribute of patient satisfaction with, and consequence adherence to, migraine acute treatment. Nevertheless, the determinants of tolerability are poorly explored. Accordingly, our objectives were: (i) in subjects receiving triptans, to contrast two methods of assessing adverse events (AEs); and (ii) to explore the relationship between migraine features and treatment attributes with tolerability. We surveyed 365 migraineurs who had been using the same triptan for at least 3 months. After prospectively treating an attack, headache characteristics and treatment response were assessed using headache calendars. Subjects also completed a standardized questionnaire, first asking about any AE and then prompting patients with a list of possible AEs. We contrasted both sets of answers and conducted logistic regression to assess if headache attributes or response to therapy influenced tolerability. Using the unprompted method, AEs occurred in 11.5-36.4% of patients, depending on the triptan used. Using the prompted method, they ranged from 26.9 to 64.3%. Chest and neck tightness were spontaneously reported by 3.5% of the sample, vs. 7.4% when prompted (P < 0.05). Chest pain was not spontaneously reported and was elicited in nine patients (2.5%, P = 0.002). Feeling groggy occurred in 5.7 and 17.5% (P < 0.001). AEs were not a function of headache severity, disability, efficacy of the drug, time to meaningful relief with the drug or recurrence of pain. The report of AEs varies dramatically with the methods of assessment. However, tolerability is not influenced by the severity of the attacks or by medication efficacy.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/estatística & dados numéricos , Transtornos de Enxaqueca/tratamento farmacológico , Agonistas do Receptor de Serotonina/efeitos adversos , Inquéritos e Questionários , Doença Aguda , Adulto , Coleta de Dados , Feminino , Humanos , Modelos Logísticos , Masculino , Prontuários Médicos , Estudos Prospectivos , Agonistas do Receptor de Serotonina/administração & dosagem , Índice de Gravidade de Doença
11.
J Pediatr Urol ; 4(2): 138-40, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18631910

RESUMO

OBJECTIVE: Hydrocele and testicular edema caused by division of lymphatic vessels during varicocelectomy could lead to decrease in testicular function. In-vivo methylene blue mapping of testicular lymphatic vessels should prevent damage to the lymphatic system. MATERIALS AND METHODS: We retrospectively compared outcomes for 46 patients who received an intraparenchymal injection of 0.25 ml of vital dye (isosulphan blue) before a laparoscopic or an inguinal/subinguinal spermatic vein ligation with 93 controls in whom no mapping technique was adopted. RESULTS: Methylene blue mapping of testicular lymphatics reduced the incidence of postvaricocelectomy hydrocele from 6.4% (6/93) to 2.1% (1/46); the incidence of hydrocele was 0% in all cases of successful lymphatic mapping. CONCLUSION: Mapping of testicular lymphatic drainage with intraparenchymal vital dye is an easy, safe, rapid and cost-free technique. We stress the importance of sparing the lymphatic system to ensure the best andrological outcome.


Assuntos
Sistema Linfático/anatomia & histologia , Azul de Metileno , Complicações Pós-Operatórias/prevenção & controle , Hidrocele Testicular/prevenção & controle , Varicocele/cirurgia , Adolescente , Criança , Edema/epidemiologia , Edema/prevenção & controle , Humanos , Incidência , Laparoscopia , Sistema Linfático/metabolismo , Sistema Linfático/cirurgia , Masculino , Azul de Metileno/farmacocinética , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Hidrocele Testicular/epidemiologia
12.
Eur J Ophthalmol ; 16(2): 274-8, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16703546

RESUMO

PURPOSE: This study was designed to evaluate the prevalence of Helicobacter pylori infection in patients with central serous chorioretinopathy (CSC). METHODS: Retrospective observational case series. A group of 23 patients (22 men and 1 woman, age range 34-62 years, median age 47 years) with diagnosis of CSC, confirmed by fluorescein angiogram, and a control group of 23 consecutive patients (22 men and 1 woman, age range 41-69 years, median age 50 years) referred to our Department for retinal disease other than CSC were studied. Each patient provided peripheral venous blood samples and a stool specimen, which were analyzed at the Department of Gastroenterology and Microbiology at the same university. H. pylori infection was determined by measurement of IgG anti-bodies to H. pylori and by determination of H. pylori antigens in the stool specimens by enzyme-linked immunosorbent assay technique. Patients were defined as H. pylori infected if both tests were positive. RESULTS: The prevalence of H. pylori infection was 78.2% (95% CI, 56%-92%) in CSC patients and 43.5% (95% CI, 23%-65%) in control subjects (p<0.03 by two-tail ed Fisher exact test). The odds ratio for CSC associated with H. pylori infection was 4.6 (95% CI 1.28-16.9). CONCLUSIONS: The results of this study show that the prevalence of H. pylori infection seems to be significantly higher in patients with CSC than in control s. H. pylori infection may represent a risk factor in patients with CSC.


Assuntos
Doenças da Coroide/epidemiologia , Infecções Oculares Bacterianas/epidemiologia , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/isolamento & purificação , Doenças Retinianas/epidemiologia , Adulto , Idoso , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/análise , Doenças da Coroide/microbiologia , Ensaio de Imunoadsorção Enzimática , Infecções Oculares Bacterianas/microbiologia , Fezes/microbiologia , Feminino , Angiofluoresceinografia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/imunologia , Humanos , Imunoglobulina G/análise , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Doenças Retinianas/microbiologia , Estudos Retrospectivos , Fatores de Risco
13.
G Ital Med Lav Ergon ; 27(3): 326-8, 2005.
Artigo em Italiano | MEDLINE | ID: mdl-16240586

RESUMO

Nanoparticles of organic carbon (NOC) are formed in combustion of hydrocarbon-rich fuels and have been detected in vehicle exhausts, suggesting their presence in urban atmospheres. Epidemiological studies showed that some causal relationships exist between particle concentration in the air and a wide range of health effects, but no toxicological studies are reported on the potential health risk of particles smaller than 4 nm. The present study investigated the mutagenicity and the reactivity of NOC collected in water samples from the exhausts of diesel and gasoline engines. Mutagenicity was tested following the Ames Test, with and without metabolic activation. Reactivity was investigated by using a new approach aimed to identify electrophilic agents present in the sample material, which if introduced into the organism, could interact with nucleophilic sites of biological macromolecules (DNA and proteins), forming adducts. Given the large number of nucleophilc sites within biological macromolecules, the complexity of NOC, and the inexact knowledge of its chemical structure, this approach was simplified by examining in vitro interactions between NOC particles and model peptides through LCIMS analyses of incubation mixtures The results indicate a high reactivity and, in several cases, the mutagenicity of NOCs, thus calling for suitable biomarkers assess NOC exposure associated with vehicle emissions.


Assuntos
Testes de Mutagenicidade/métodos , Mutagênicos/toxicidade , Nanoestruturas , Emissões de Veículos/toxicidade , Adutos de DNA , Óleos Combustíveis/toxicidade , Humanos , Salmonella typhimurium/efeitos dos fármacos
14.
Pediatr Med Chir ; 27(3-4): 112-6, 2005.
Artigo em Italiano | MEDLINE | ID: mdl-16910462

RESUMO

The Authors report a case of congenital megacystis without other anomalies, diagnosed in a 27GW female fetus. At prenatal counselling the diagnostic hypothesis formulated were obstructive uropathy (cloacal malformation, uro-genital sinus, urethral atresia), functional alteration (neurogenic bladder, primitive myopathies) or Prune Belly Syndrome (rare in females). The outcome following treatment suppose a visceral myopathy, for this condition, however definitive etiology is obscure.


Assuntos
Doenças Fetais , Doenças da Bexiga Urinária/congênito , Bexiga Urinária/anormalidades , Aconselhamento , Diagnóstico Diferencial , Feminino , Feto , Humanos , Gravidez , Segundo Trimestre da Gravidez , Ultrassonografia Pré-Natal , Doenças da Bexiga Urinária/diagnóstico por imagem
15.
Endocrinology ; 144(10): 4298-305, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12959980

RESUMO

The Src homology 2-containing tyrosine phosphatase, Shp-2, is a crucial enzyme that mediates intracellular signaling and is implicated in cell proliferation and differentiation. Here we investigated the involvement of the Shp-2 tyrosine phosphatase in determining the downstream signaling pathways initiated by the Ret oncogene, carrying either the cysteine 634 to tyrosine or the methionine 918 to threonine substitutions. These mutations convert the receptor tyrosine kinase, Ret, into a dominant transforming protein and induce constitutive activation of its intrinsic tyrosine kinase activity leading to congenital and sporadic cancers in neuroendocrine organs. Using the PC12, rat pheochromocytoma cell line, as model system, we show that Shp-2 mediates immediate-early gene expression if induced by either of the mutant alleles. Furthermore, we show that Shp-2 activity is required for RetM918T-induced Akt activation. The results indicate that Shp-2 is a downstream mediator of the mutated receptors RetC634Y and RetM918T, thus suggesting that it may act as a limiting factor in Ret-associated endocrine tumors, in the neoplastic syndromes multiple endocrine neoplasia types 2A and 2B.


Assuntos
Membranas Intracelulares/fisiologia , Mutação/fisiologia , Proteínas Oncogênicas/genética , Proteínas Tirosina Fosfatases/metabolismo , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais/fisiologia , Animais , Diferenciação Celular/fisiologia , Linhagem Celular , Sobrevivência Celular/fisiologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial , Peptídeos e Proteínas de Sinalização Intracelular , Fatores de Crescimento Neural/metabolismo , Proteínas Oncogênicas/metabolismo , Células PC12/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Proteínas Proto-Oncogênicas c-ret , Ratos , Receptores Proteína Tirosina Quinases/metabolismo
16.
Cell Death Differ ; 10(2): 175-84, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12700645

RESUMO

Apoptosis control in adult testis is crucial to achieve normal spermatogenesis. In this study c-FLIP, an apoptosis-modulating protein, was investigated. In Western blot and immunohistochemical analyses, the 55 KDa c-FLIP long isoform (c-FLIP(L)) was found to be expressed strongly in spermatocytes and spermatids, at low levels in spermatogonia and at almost undetectable levels in Sertoli cells. This expression pattern was confirmed by Northern blot analyses. Further experiments carried out on GC-1spg germ cell line revealed that reducing c-FLIP(L) expression increases Fas-dependent apoptosis. Conversely, restoring c-FLIP(L) expression reduces this response to control levels. Caspase-10 expression was found to match c-FLIP(L) expression pattern; further, caspase-10 activation upon anti-Fas treatment inversely correlated with c-FLIP(L) expression. Finally, TUNEL staining of seminiferous tubules incubated with anti-Fas antibody showed that apoptosis occurs mostly in basally located germ cells, indicating that such cells, expressing low levels of c-FLIP(L), are sensitive to Fas-mediated apoptosis. These data indicate for the first time that c-FLIP(L) might control germ cell apoptosis and caspase activity in the adult testis.


Assuntos
Apoptose , Proteínas de Transporte/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Testículo/metabolismo , Animais , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD , Caspases/metabolismo , Linhagem Celular/efeitos dos fármacos , Células Cultivadas , Ativação Enzimática , Células Germinativas/citologia , Masculino , Camundongos , Camundongos Endogâmicos , Oligonucleotídeos Antissenso/farmacologia , Isoformas de Proteínas/metabolismo , Túbulos Seminíferos , Células de Sertoli/citologia , Células de Sertoli/metabolismo , Espermátides/citologia , Espermátides/metabolismo , Espermatócitos/citologia , Espermatócitos/metabolismo , Espermatogônias/citologia , Espermatogônias/metabolismo , Testículo/química , Testículo/citologia , Receptor fas/metabolismo
17.
Chemosphere ; 51(10): 1079-90, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12718973

RESUMO

UV-visible extinction and scattering and two extra situ sampling techniques: atomic force microscopy (AFM) and differential mobility analysis (DMA) are used to follow the evolution of the particles formed in flames. These particle sizing techniques were chosen because of their sensitivity to detect inception particles, which have diameters, d<5 nm, too small to be observed with typical particle measurement instrumentation. The size of the particles determined by AFM and DMA compares well with the size determined by in situ optical measurements, indicating that the interpretation of the UV-visible optical signal is quite good, and strongly showing the presence of d=2-4 nm particles. UV-visible extinction measurements are also used to determine the concentration of d=2-4 nm particles at the exhausts of practical combustion systems. A numerical model, able to reproduce the experimentally observed low coagulation rate of nanoparticles with respect to soot particles, is used to investigate the operating conditions in the combustion chamber and exhaust system for which 2-4 nm particles survive the exhaust or grow to larger sizes. Combustion generated nanoparticles are suspected to affect human and environmental health because of their affinity for water, small size, low rate of coagulation, and large surface area/weight ratio. The ability to isolate nanoparticles from soot particles in hydrosols collected from combustion may be useful for future analysis by a variety of techniques and toxicological assays.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Modelos Teóricos , Incineração , Microscopia de Força Atômica , Tamanho da Partícula , Eliminação de Resíduos , Espectrofotometria Ultravioleta
18.
Chemosphere ; 51(10): 1091-6, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12718974

RESUMO

The combustion of heavy fuel oil for power generation is a great source of carbonaceous and inorganic particle emissions, even though the combustion technologies and their efficiency are improving. The information about the size distribution function of the particles originated by trace metals present into the fuels is not adequate. In this paper, we focused our attention on the larger distribution mode of both the carbonaceous and metallic particles. Isokinetic sampling was performed at the exhausts of two typical heavy oil flames and the samples were size-segregated by mean of an 8-stages Andersen impactor. Further investigation performed on the samples using electronic microscopy coupled with X-ray analysis (EDX) evidenced the presence of solid spherical particles, called plerosphere(1) as analogy with cenosphere, with typical dimensions ranging between 200 nm and 2-3 microm, whose atomic composition contains a large amount of the trace metals present in the parent oils (Fe, V, Ni, etc). EDX analyses revealed that the metal concentration increases as the plerosphere dimension decreases.


Assuntos
Poluentes Atmosféricos/análise , Óleos Combustíveis , Metais Pesados/análise , Centrais Elétricas , Carbono/análise , Incineração , Tamanho da Partícula
19.
Andrologia ; 35(1): 64-70, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12558530

RESUMO

The Fas system is involved in the control of immune system homeostasis and nonfunctional Fas system leads to autoimmune disease in mice and humans. The Fas system is a mechanism through which cells expressing Fas ligand (FasL) induce apoptosis of Fas expressing cells. In mouse and rat, the testis represents the main source of constitutive FasL in the body. The roles so far proposed for this molecule in the testis, such as maintenance of immunoprivilege and regulation of physiological germ cell apoptosis, need to be reconsidered as both hypotheses are based on an erroneous cellular location of FasL in the seminiferous epithelium. Recently, we demonstrated that in rodents FasL mRNA is present in germ cells and not in Sertoli cells, and that FasL protein is displayed on the surface of spermatozoa. Here we propose that, for the mouse spermatozoa, the FasL may represent a self-defence mechanism against lymphocytes present in the female genital tract. To verify this hypothesis, we performed crossings between males gld, with nonfunctional FasL, and syngenic or nonsyngenic females. We observed a significant decrease of litter size in outbred crossings with gld males compared with wild-type males, suggesting a possible role of FasL in immunoprotection of the sperm in the female genital tract. The possibility that in humans, by analogy with mouse, FasL plays a self-protective role for the spermatozoon cannot be excluded, and awaits experimental information on the expression of FasL on human sperm cells.


Assuntos
Glicoproteínas de Membrana/fisiologia , Epitélio Seminífero/química , Receptor fas/fisiologia , Animais , Apoptose , Proteína Ligante Fas , Expressão Gênica , Humanos , Imunidade , Masculino , Glicoproteínas de Membrana/genética , Camundongos , Modelos Biológicos , RNA Mensageiro/análise , Espermatozoides/química , Testículo
20.
Eur J Pediatr Surg ; 12(1): 24-7, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11967755

RESUMO

The authors report their experience with one-trocar transumbilical laparoscopic assisted appendectomy (TULAA). From January 1998 to June 2000, 150 patients underwent appendectomy using this technique. Ages ranged from 2.5 to 17.4 years. The procedure was completed using only one trocar in 116 cases (77.3%); in 28 patients (18.7%) one or two additional cannulas were needed. Conversion to open surgery became necessary in 6 cases (4%). Mean operative time was 35 minutes, mean hospital stay 3.5 days. There were no major complications and no mortality in this series. The advantages of a one-trocar appendectomy compared with open surgery are the same as those reported for conventional laparoscopic appendectomy: i.e., excellent exploration of the abdominal cavity, the possibility of discovering extra-appendiceal lesions, easy and rapid localization of the appendix and a shorter hospital stay. The additional advantages of TULAA compared with conventional laparoscopic appendectomy are a low rate of intraoperative incidents, minimal scarring, less postoperative pain and a more rapid return to unrestricted activities.


Assuntos
Apendicectomia/métodos , Apendicite/cirurgia , Laparoscopia/métodos , Doença Aguda , Adolescente , Criança , Pré-Escolar , Estudos de Viabilidade , Feminino , Humanos , Complicações Intraoperatórias/epidemiologia , Tempo de Internação , Masculino , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...