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1.
Annu Rev Physiol ; 84: 559-583, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-34699268

RESUMO

Nephrolithiasis is a worldwide problem with increasing prevalence, enormous costs, and significant morbidity. Calcium-containing kidney stones are by far the most common kidney stones encountered in clinical practice, and thus, hypercalciuria is the greatest risk factor for kidney stone formation. Hypercalciuria can result from enhanced intestinal absorption, increased bone resorption, or altered renal tubular transport. Kidney stone formation is complex and driven by high concentrations of calcium-oxalate or calcium-phosphate in the urine. After discussing the mechanism mediating renal calcium salt precipitation, we review recent discoveries in renal tubular calcium transport from the proximal tubule, thick ascending limb, and distal convolution. Furthermore, we address how calcium is absorbed from the intestine and mobilized from bone. The effect of acidosis on bone calcium resorption and urinary calcium excretion is also considered. Although recent discoveries provide insight into these processes, much remains to be understood in order to provide improved therapies for hypercalciuria and prevent kidney stone formation.


Assuntos
Cálcio , Cálculos Renais , Oxalato de Cálcio/urina , Cálcio da Dieta , Humanos , Hipercalciúria/complicações
2.
BMC Gastroenterol ; 23(1): 181, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37226091

RESUMO

BACKGROUND: Transarterial radioembolization with yttrium-90 (Y-90 TARE) microspheres therapy has demonstrated positive clinical benefits for the treatment of liver metastases from colorectal cancer (lmCRC). This study aims to conduct a systematic review of the available economic evaluations of Y-90 TARE for lmCRC. METHODS: English and Spanish publications were identified from PubMed, Embase, Cochrane, MEDES health technology assessment agencies, and scientific congress databases published up to May 2021. The inclusion criteria considered only economic evaluations; thus, other types of studies were excluded. Purchasing-power-parity exchange rates for the year 2020 ($US PPP) were applied for cost harmonisation. RESULTS: From 423 records screened, seven economic evaluations (2 cost-analyses [CA] and 5 cost-utility-analyses [CUA]) were included (6 European and 1 USA). All included studies (n = 7) were evaluated from a payer and the social perspective (n = 1). Included studies evaluated patients with unresectable liver-predominant metastases of CRC, refractory to chemotherapy (n = 6), or chemotherapy-naïve (n = 1). Y-90 TARE was compared to best supportive care (BSC) (n = 4), an association of folinic acid, fluorouracil and oxaliplatin (FOLFOX) (n = 1), and hepatic artery infusion (HAI) (n = 2). Y-90 TARE increased life-years gained (LYG) versus BSC (1.12 and 1.35 LYG) and versus HAI (0.37 LYG). Y-90 TARE increased the quality-adjusted-life-year (QALY) versus BSC (0.81 and 0.83 QALY) and versus HAI (0.35 QALY). When considering a lifetime horizon, Y-90 TARE reported incremental cost compared to BSC (range 19,225 to 25,320 $US PPP) and versus HAI (14,307 $US PPP). Y-90 TARE reported incremental cost-utility ratios (ICURs) between 23,875 $US PPP/QALY to 31,185 $US PPP/QALY. The probability of Y-90 TARE being cost-effective at £ 30,000/QALY threshold was between 56% and 57%. CONCLUSIONS: Our review highlights that Y-90 TARE could be a cost-effective therapy either as a monotherapy or when combined with systemic therapy for treating ImCRC. However, despite the current clinical evidence on Y-90 TARE in the treatment of ImCRC, the global economic evaluation reported for Y-90 TARE in ImCRC is limited (n = 7), therefore, we recommend future economic evaluations on Y-90 TARE versus alternative options in treating ImCRC from the societal perspective.


Assuntos
Neoplasias Colorretais , Neoplasias Hepáticas , Feminino , Gravidez , Humanos , Análise Custo-Benefício , Microesferas , Radioisótopos de Ítrio/uso terapêutico , Neoplasias Hepáticas/radioterapia
3.
BMC Gastroenterol ; 22(1): 326, 2022 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-35780112

RESUMO

BACKGROUND: Transarterial radioembolization (TARE) with yttrium-90 microspheres is a clinically effective therapy for hepatocellular carcinoma (HCC) treatment. This study aimed to perform a systematic review of the available economic evaluations of TARE for the treatment of HCC. METHODS: The Preferred Reported Items for Systematic reviews and Meta-Analyses guidelines was followed by applying a search strategy across six databases. All studies identified as economic evaluations with TARE for HCC treatment in English or Spanish language were considered. Costs were adjusted using the 2020 US dollars based on purchasing-power-parity ($US PPP). RESULTS: Among 423 records screened, 20 studies (6 cost-analyses, 3 budget-impact-analyses, 2 cost-effectiveness-analyses, 8 cost-utility-analyses, and 1 cost-minimization analysis) met the pre-defined criteria for inclusion. Thirteen studies were published from the European perspective, six from the United States, and one from the Canadian perspectives. The assessed populations included early- (n = 4), and intermediate-advanced-stages patients (n = 15). Included studies were evaluated from a payer perspective (n = 20) and included both payer and social perspective (n = 2). TARE was compared with transarterial chemoembolization (TACE) in nine studies or sorafenib (n = 11). The life-years gained (LYG) differed by comparator: TARE versus TACE (range: 1.3 to 3.1), and TARE versus sorafenib (range: 1.1 to 2.53). Of the 20 studies, TARE was associated with lower treatment costs in ten studies. The cost of TARE treatment varied widely according to Barcelona Clinic Liver Cancer (BCLC) staging system and ranged from 1311 $US PPP/month (BCLC-A) to 71,890 $US PPP/5-years time horizon (BCLC-C). The incremental cost-utility ratio for TARE versus TACE resulted in a 17,397 $US PPP/Quality-adjusted-Life-Years (QALY), and for TARE versus sorafenib ranged from dominant (more effectiveness and lower cost) to 3363 $US PPP/QALY. CONCLUSIONS: Economic evaluations of TARE for HCC treatment are heterogeneous. Overall, TARE is a cost-effective short- and long-term therapy for the treatment of intermediate-advanced HCC.


Assuntos
Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Canadá , Carcinoma Hepatocelular/radioterapia , Análise Custo-Benefício , Feminino , Humanos , Neoplasias Hepáticas/radioterapia , Microesferas , Gravidez , Sorafenibe/uso terapêutico
4.
Eur J Nucl Med Mol Imaging ; 48(11): 3631-3642, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33797597

RESUMO

PURPOSE: The aim of our study was to investigate the correlation between cfDNA concentration and fragment size fraction with FDG PET/CT- and CT-derived parameters in untreated NSCLC patient. METHODS: Fifty-three patients diagnosed of locally advanced or metastatic NSCLC who had undergone FDG PET/CT, CT and cfDNA analysis prior to any treatment were included in this retrospective study. CfDNA concentration was measured by fluorometry and fragment size fractions were determined by microchip electrophoresis. [18F]F-FDG PET/CT was performed and standardised uptake values (SUV), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated for primary, extrapulmonary and total disease. CT scans were evaluated according to RECIST 1.1 criteria. RESULTS: CfDNA concentration showed a positive correlation with extrapulmonary MTV (r2 = 0.36, P = 0.009), and extrapulmonary TLG (r2 = 0.35, P = 0.009) and their whole-body (wb) ratios. Higher concentrations of total cfDNA were found in patients with liver lesions. Short fragments of cfDNA (100-250 bp) showed a positive correlation with extrapulmonary MTV (r2 = 0.49, P = 0.0005) and extrapulmonary TLG (r2 = 0.39, P = 0.006) and their respective wb ratios, and a negative correlation with SUVmean (r2 = -0.31, P = 0.03) and SUVmean/SUVmax ratio (r2 = -0.34, P = 0.02). A higher fraction of short cfDNA fragments was found in patients with liver and pleural lesions. CONCLUSIONS: This study supports the hypothesis that cfDNA concentration and short cfDNA fragment size fraction reflect the tumour burden as well as metabolic activity in advanced NSCLC patients. This suggests their suitability as complementary tests for a more accurate diagnosis of tumour metabolic behaviour and to allow personalised therapies.


Assuntos
Ácidos Nucleicos Livres , Neoplasias Pulmonares , Fluordesoxiglucose F18 , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Prognóstico , Estudos Retrospectivos , Carga Tumoral
5.
J Antimicrob Chemother ; 72(6): 1714-1722, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28204495

RESUMO

Background: Previous studies showed development of daptomycin non-susceptibility (DNS: MIC >4 mg/L) in Enterococcus faecalis infections. However, no studies have assessed the efficacy of the combination of daptomycin/ampicillin against E. faecalis strains developing DNS in the experimental endocarditis (EE) model. Objectives: To assess the in vitro and in vivo efficacy of daptomycin at 10 mg/kg/day, daptomycin/ampicillin and ampicillin/ceftriaxone against two high-level aminoglycoside-resistant E. faecalis strains, one developing DNS after in vitro exposure to daptomycin and another that did not (DS). Methods: Subculture of 82 E. faecalis strains from patients with endocarditis with daptomycin MICs, time-kill and in vivo experiments using the EE model. Results: 33% of the strains (27 of 82) displayed DNS after subculture with daptomycin. Daptomycin MIC rose from 0.5-2 to 8-16 mg/L. In time-kill experiments, when using a high inoculum (10 8 cfu/mL), daptomycin/ampicillin was synergistic for one-third of DS strains and none of DNS strains, while ampicillin/ceftriaxone retained synergy in all cases. In the EE model, daptomycin did not significantly reduce cfu/g from vegetations compared with control against either strain, while daptomycin/ampicillin reduced significantly more cfu/g than daptomycin against the DS strain, but not against the DNS strain [2.9 (2.0-4.1) versus 6.1 (4.5-8.0); P = 0.002]. Ampicillin/ceftriaxone was synergistic and bactericidal against both strains, displaying the same activity as daptomycin/ampicillin against the DS strain. Conclusions: Performance of an Etest for daptomycin MIC after subculture with daptomycin inhibitory doses on strains of high-level aminoglycoside-resistant E. faecalis endocarditis may be an easy test to predict the in vivo efficacy of daptomycin/ampicillin.


Assuntos
Aminoglicosídeos/farmacologia , Ampicilina/administração & dosagem , Antibacterianos/administração & dosagem , Daptomicina/administração & dosagem , Endocardite Bacteriana/tratamento farmacológico , Enterococcus faecalis/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Ampicilina/uso terapêutico , Animais , Antibacterianos/farmacologia , Ceftriaxona/farmacologia , Daptomicina/farmacologia , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana , Sinergismo Farmacológico , Quimioterapia Combinada , Endocardite Bacteriana/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Coelhos
6.
J Viral Hepat ; 22(1): 18-24, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25131721

RESUMO

Hepatitis C virus (HCV) infection is frequent among patients with alcohol use disorders. We aimed to analyse the impact of HCV infection on survival of patients seeking treatment for alcohol use. This was a longitudinal study in a cohort of patients who abused alcohol recruited in two detoxification units. Socio-demographic and alcohol use characteristics, liver function tests for the assessment of alcohol-related liver disease and HCV and HIV infection serologies were obtained at admission. Patients were followed until December 2008; causes of death were ascertained through clinical records and death registry. Cox models were used to analyse predictors of death. A total of 675 patients (79.7% men) were admitted; age at admission was 43.5 years (IQR: 37.9-50.2 years), duration of alcohol abuse was 18 years (IQR: 11-24 years), and median alcohol consumption was 200 g/day (IQR: 120-275 g/day). Distribution of patients according to viral infections was as follows: 75.7% without HCV or HIV infection, 14.7% HCV infection alone and 8.1% HCV/HIV coinfection. Median follow-up was 3.1 years (IQR: 1.5-5.1 years) accounting for 2,345 person-years. At the end of study, 78 patients (11.4%) had died. In the multivariate analysis, age at admission (HR = 1.71, 95%CI: 1.05-2.80), alcohol-related liver disease (HR = 3.55, 95%CI: 1.93-6.53) and HCV/HIV co-infection (HR = 3.86 95%CI: 2.10-7.11) were predictors of death. Younger patients (≤43 years) with HCV infection were more likely to die than those without viral infections (HR = 3.1, 95%CI: 1.3-7.3; P = 0.007). Among patients with alcohol-related liver disease, mortality rate was high, irrespective of viral infections. These data show that HCV infection confers a worse prognosis in patients with alcohol use disorders.


Assuntos
Alcoolismo/complicações , Alcoolismo/mortalidade , Hepatite C/complicações , Hepatite C/mortalidade , Adulto , Estudos de Coortes , Comorbidade , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Medição de Risco , Análise de Sobrevida
7.
Artigo em Inglês | MEDLINE | ID: mdl-35668016

RESUMO

AIM: The aim of this study is the implementation in a Hospital Radiopharmacy Unit of a risk analysis methodology in order to proactively identify possible failure modes and prioritize corrective measures. MATERIALS AND METHODS: By means of the failure modes and effects analysis (FMEA), the possible failure modes of each of the stages of the processes of prescription, preparation, and administration of radiopharmaceuticals for diagnostic and therapy were identified. From the variables of severity, probability and detectability, the risk was quantified using the Risk Priority Number (RPN) for each failure mode, sub-process, and type of radiopharmaceutical. Improvement measures were established and the reduction in the RPN value was calculated. RESULTS: A total of 96 failure modes were identified (58 for diagnostic radiopharmaceuticals and 38 for therapy). Biunivocal identification of the patient with the radiopharmaceutical is the failure mode with the highest RPN (60) and the radiolabeling cell sub-process the one that has the highest risk (RPN 286). As a result of the improvement measures, the overall RPN was reduced by 22% for diagnostic radiopharmaceuticals and 20% for therapy. This reduction would be 46% and 31% respectively if radiopharmacy software and a barcode technology in the administration were implemented. CONCLUSIONS: The application of the FMEA methodology as a risk analysis tool allows to identify the critical points of the processes related to radiopharmaceuticals and prioritize measures to reduce the risk.


Assuntos
Análise do Modo e do Efeito de Falhas na Assistência à Saúde , Hospitais , Humanos , Compostos Radiofarmacêuticos/uso terapêutico , Medição de Risco
8.
Osteoporos Int ; 22(1): 281-7, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20229199

RESUMO

UNLABELLED: This study evaluates the efficacy of low doses of pamidronate after renal transplantation to prevent bone loss in osteopenic patients. Results show that pamidronate is safe and significantly reduced spinal bone loss when administered immediately after renal transplantation. INTRODUCTION: The purpose of this work is to evaluate the efficacy of two intravenous infusions of pamidronate in the immediate post-transplant period in a renal transplant (RT) population. METHODS: In this 12-month, randomized, double-blind, multicenter trial, 39 kidney recipients with diagnosed osteopenia received two doses of 30 mg of disodium pamidronate (n = 24) or placebo (n = 15), at surgery and 3 months post-RT. All patients received calcium and vitamin D. Bone density of the lumbar spine and total femur was measured by dual-energy X-ray absorptiometry (DXA) and X-rays were performed at RT, 6 and 12 months post-RT. Biochemical and hormonal determinations were performed before and after treatment. RESULTS: Pamidronate significantly reduced spinal bone loss, but no significant benefit was found for the incidence of fractures. Elevated baseline intact parathyroid hormone (iPTH) and bone remodeling markers returned to normal levels 3 months post-RT. However, normal procollagen type I N propeptide (PINP) concentrations were only maintained in the pamidronate group. After RT, a comparable graft function was observed in both groups according to creatinine values, 25-hydroxyvitamin-D (25-OH-D) levels were improved, and serum calcium levels normalized after a transient fall during the first 3 months. CONCLUSION: A low dose of pamidronate prevents bone loss in osteopenic patients when administered immediately after RT.


Assuntos
Conservadores da Densidade Óssea/administração & dosagem , Doenças Ósseas Metabólicas/tratamento farmacológico , Difosfonatos/administração & dosagem , Transplante de Rim/efeitos adversos , Adulto , Idoso , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/efeitos adversos , Conservadores da Densidade Óssea/uso terapêutico , Doenças Ósseas Metabólicas/etiologia , Doenças Ósseas Metabólicas/fisiopatologia , Remodelação Óssea/efeitos dos fármacos , Creatinina/sangue , Difosfonatos/efeitos adversos , Difosfonatos/uso terapêutico , Métodos Epidemiológicos , Feminino , Fêmur/fisiopatologia , Colo do Fêmur/fisiopatologia , Humanos , Infusões Intravenosas , Vértebras Lombares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fraturas por Osteoporose/prevenção & controle , Pamidronato , Cuidados Pós-Operatórios/métodos , Resultado do Tratamento
9.
J Acoust Soc Am ; 129(1): 122-31, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21302994

RESUMO

The effect of liquid compressibility on the dynamics of a single, spherical cavitating bubble is studied. While it is known that compressibility damps the amplitude of bubble rebounds, the extent to which this effect is accurately captured by weakly compressible versions of the Rayleigh-Plesset equation is unclear. To clarify this issue, partial differential equations governing conservation of mass, momentum, and energy are numerically solved both inside the bubble and in the surrounding compressible liquid. Radiated pressure waves originating at the unsteady bubble interface are directly captured. Results obtained with Rayleigh-Plesset type equations accounting for compressibility effects, proposed by Keller and Miksis [J. Acoust. Soc. Am. 68, 628-633 (1980)], Gilmore, and Tomita and Shima [Bull. JSME 20, 1453-1460 (1977)], are compared with those resulting from the full model. For strong collapses, the solution of the latter reveals that an important part of the energy concentrated during the collapse is used to generate an outgoing pressure wave. For the examples considered in this research, peak pressures are larger than those predicted by Rayleigh-Plesset type equations, whereas the amplitudes of the rebounds are smaller.


Assuntos
Microbolhas , Modelos Teóricos , Ultrassom , Simulação por Computador , Análise Numérica Assistida por Computador , Oscilometria , Pressão , Propriedades de Superfície , Temperatura
10.
Nanotechnology ; 21(32): 325706, 2010 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-20647625

RESUMO

Evolution of the size, shape and composition of self-assembled InAs/InP quantum wires through the Stranski-Krastanov transition has been determined by aberration-corrected Z-contrast imaging. High resolution compositional maps of the wires in the initial, intermediate and final formation stages are presented. (001) is the main facet at their very initial stage of formation, which is gradually reduced in favour of [114] or [118], ending with the formation of mature quantum wires with {114} facets. Significant changes in wire dimensions are measured when varying slightly the amount of InAs deposited. These results are used as input parameters to build three-dimensional models that allow calculation of the strain energy during the quantum wire formation process. The observed morphological evolution is explained in terms of the calculated elastic energy changes at the growth front. Regions of the wetting layer close to the nanostructure perimeters have higher strain energy, causing migration of As atoms towards the quantum wire terraces, where the structure is partially relaxed; the thickness of the wetting layer is reduced in these zones and the island height increases until the (001) facet is removed.

11.
Nefrologia ; 30(2): 158-67, 2010.
Artigo em Espanhol | MEDLINE | ID: mdl-20098464

RESUMO

For patients with chronic renal failure who develop secondary hyperparathyroidism (SHPT), imaging techniques can be useful, especially to evaluate the location, size and functional status of parathyroid glands. This review analyzes all available imaging procedures in the context of SHPT. We evaluate: 1) Cervical ultrasound (B-mode, Doppler, colour-Doppler and power-Doppler), 2) Scintigraphic studies (Tallium, 99mTc-MIBI and 99mTc-tetrofosmin), including non-standard image acquisition techniques (Pinhole, SPECT), 3) Positron emission tomography (PET), 4) Computed tomography (CT) and magnetic resonance imaging (MRI) and 5) hybrid scanners (SPECT/CT and PET/CT). Our recommendation is that SHPT patients who are initially non responders to medical therapy should be investigated using parathyroid scintigraphy and cervical ultrasound. 99mTc-MIBI uptake can be graded in a semiquantitative scale. Intense uptake indicates a low probability of success using medical treatment and parathyroidectomy should be considered. A moderate to faint uptake indicates that a more intensive medical therapy would probably be beneficial. In the case of no uptake of 99mTc-MIBI, PET should be performed. Where this is not available, MRI could be a possible alternative.


Assuntos
Diagnóstico por Imagem , Hiperparatireoidismo Secundário/diagnóstico , Diagnóstico por Imagem/métodos , Humanos , Hiperparatireoidismo Secundário/diagnóstico por imagem , Hiperparatireoidismo Secundário/etiologia , Hiperparatireoidismo Secundário/cirurgia , Falência Renal Crônica/complicações , Imageamento por Ressonância Magnética , Glândulas Paratireoides/diagnóstico por imagem , Paratireoidectomia , Tomografia por Emissão de Pósitrons , Radiologia Intervencionista , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Sestamibi , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X , Ultrassonografia Doppler/métodos , Ultrassonografia de Intervenção
12.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-32467000

RESUMO

OBJECTIVE: To assess the diagnostic capability of PET/CT with [18F]F-Fluoromethylcholine in prostate cancer (PC) with biochemical recurrence and its therapeutic impact. MATERIAL AND METHODS: We included 108 patients, diagnosed with PC with biochemical criteria for recurrence. A PET/CT Choline scan was performed by dynamic pelvic and whole body study at 60min post-tracer injection. The relationship between the positive studies and the PSA value was analysed by classifying patients into three groups (<1.2/1.2-2/>2ng/ml), and the diagnostic capacity was assessed with respect to pelvic MRI and the impact on the therapeutic decision. RESULTS: The location of recurrence was identified in 85 of 108 patients (78.7%): 34 local, 47 pelvic lymph nodes and 58 distant lesions, including retroperitoneal, mediastinal lymph nodes and distant organ lesions (bone and lung). Second tumors were diagnosed in 4 patients. No significant differences were found in the percentage of positive studies depending on primary treatment. Patients with PSA>2ng/ml showed a higher percentage of disease detection than patients with a lower PSA level, with significant differences (p<0.0001). PET/CT [18F]F-Choline was able to detect local disease, not previously known from MRI, in 29.41% of patients. PET/CT Choline had an impact on therapeutic management in 67 of 108 patients (62%). CONCLUSIONS: PET/CT with [18F]F-Fluoromethylcholine is a useful tool in the detection of locoregional and disseminated disease of PC treated with suspicion of recurrence, providing a change in therapeutic management in 62% of patients.


Assuntos
Adenocarcinoma/secundário , Neoplasias Ósseas/secundário , Colina/análogos & derivados , Radioisótopos de Flúor , Calicreínas/sangue , Neoplasias Pulmonares/secundário , Recidiva Local de Neoplasia/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Antígeno Prostático Específico/sangue , Neoplasias da Próstata/diagnóstico por imagem , Compostos Radiofarmacêuticos , Adenocarcinoma/sangue , Adenocarcinoma/diagnóstico por imagem , Adenocarcinoma/terapia , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/diagnóstico por imagem , Gerenciamento Clínico , Humanos , Achados Incidentais , Neoplasias Pulmonares/diagnóstico por imagem , Metástase Linfática/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Segunda Neoplasia Primária/diagnóstico por imagem , Estudos Prospectivos , Neoplasias da Próstata/sangue , Neoplasias da Próstata/terapia , Sensibilidade e Especificidade
13.
Nanotechnology ; 20(47): 475202, 2009 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-19858562

RESUMO

We have fabricated an array of closely spaced quantum dashes starting from a planar array of self-assembled semiconductor quantum wires. The array is embedded in a metallic nanogap which we investigate by micro-photoluminescence as a function of a lateral electric field. We demonstrate that the net electric charge and emission energy of individual quantum dashes can be modified externally with the performance limited by the size inhomogeneity of the self-assembling process.

14.
Ultramicroscopy ; 109(2): 172-6, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19062188

RESUMO

A phenomenological method is developed to determine the composition of materials, with atomic column resolution, by analysis of integrated intensities of aberration-corrected Z-contrast scanning transmission electron microscopy images. The method is exemplified for InAs(x)P(1-x) alloys using epitaxial thin films with calibrated compositions as standards. Using this approach we have determined the composition of the two-dimensional wetting layer formed between self-assembled InAs quantum wires on InP(001) substrates.

15.
Kidney Int ; 73(10): 1151-8, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18368028

RESUMO

Mutations in the B1 subunit of the multisubunit vacuolar ATPase cause autosomal-recessive distal renal tubular acidosis and sensorineural deafness. Here, we report a novel frameshift mutation that truncates the C-terminus of the human B1 subunit. This mutant protein failed to assemble with other subunits in the cytosol to form the complex that can be targeted to vesicular structures in mammalian cells. Loss of proton pump activity was demonstrated in a functional complementation assay in B-subunit null yeast. The mutation caused loss of a discreet C-terminal region critical for subunit interaction not related to the C-terminal PDZ motif. Co-expression studies failed to demonstrate dominant negative effects of this truncated mutant over wild-type B1. Analysis of 12 reported B1 subunit missense mutations showed one polymorphic allele had intact pump function, two point mutants had intact assembly but defective proton pumping, and the remaining nine had disrupted assembly with no pump function. One presumed polymorphic allele was actually an inactivating mutation. Our study shows that multiple mechanisms of pump dysfunction result from B1 subunit mutations with a common outcome being defective assembly. Polymorphisms of the B1 subunit in the general population may affect renal acidification and urinary chemistry.


Assuntos
Acidose Tubular Renal/genética , Mutação de Sentido Incorreto , ATPases Vacuolares Próton-Translocadoras/genética , Acidose Tubular Renal/etiologia , Humanos
16.
Minerva Endocrinol ; 33(3): 203-12, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18846026

RESUMO

Preoperative imaging has proved its use successful in the localization of solitary parathyroid adenomas in patients with suspected primary hyperparathyroidism. However, due to multiglandular disease at presentation patients with renal hyperparathyroidism need to be analyzed separately, making the usefulness of imaging techniques controversial. Recently, improved methods of functional imaging like parathyroid scan with 99mTc-sestamibi or positron emission tomography, especially when combined with computed tomography, can provide additional quantitative and qualitative information that has yet to be assessed. Nuclear medicine procedures could prove useful not only in preoperative diagnosis, but also in the selection of medical or surgical therapeutic alternatives in secondary hyperparathyroidism patients. There is evidence that 99mTc-sestamibi uptake in parathyroid hyperplasia or adenoma is related to biochemical markers of parathyroid function. We are only beginning to identify the factors involved in radiotracer uptake by parathyroid cells and how it can be modulated to obtain more accurate results. This review analyzes the current use of non-invasive imaging modalities in patients with secondary hyperparathyroidism, taking into account the latest trends in the field combining anatomic and functional modalities and the relevant factors linked to radiotracer uptake in abnormal hyperfunctioning parathyroid glands.


Assuntos
Diagnóstico por Imagem/métodos , Hiperparatireoidismo Secundário/diagnóstico por imagem , Cálcio/uso terapêutico , Humanos , Hiperparatireoidismo Secundário/tratamento farmacológico , Hiperparatireoidismo Secundário/cirurgia , Hipocalcemia/complicações , Hipocalcemia/tratamento farmacológico , Compostos Organofosforados , Compostos de Organotecnécio , Paratireoidectomia , Tomografia por Emissão de Pósitrons , Cuidados Pré-Operatórios , Compostos Radiofarmacêuticos/farmacocinética , Tecnécio Tc 99m Sestamibi/farmacocinética , Distribuição Tecidual , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X , Ultrassonografia
17.
Rev Esp Med Nucl ; 27(6): 430-5, 2008.
Artigo em Espanhol | MEDLINE | ID: mdl-19094902

RESUMO

AIM: To evaluate the usefulness of (99m)Tc-Sulphur colloid when combined with leukocyte scintigraphy in suspected prosthetic hip infection, comparing the results with information from (99m)Tc-HMPAO-leukocyte scintigraphy alone. MATERIALS AND METHODS: Seventy patients (42 women, 28 men; mean age 68 +/- 13 years) with painful hip prostheses and suspicion of infection were evaluated prospectively. All patients had bone scintigraphy, (99m)Tc-HMPAO-labelled white blood cell scintigraphy and (99m)Tc-Sulphur colloid bone marrow scintigraphy. ESR and CRP levels were measured in all patients. The final diagnosis was made with microbiological findings or by clinical follow up of at least 12 months. RESULTS: Infections were diagnosed in 12 of the 70 patients (3 coagulase-negative Staphylococcus, 2 Staphylococcus aureus, 2 Staphylococcus epidermidis, 2 enterococcus and 3 polymicrobial agents). ESR and CRP values were higher in patients with infection than in patients without infection (51.8 +/- 29.4 vs. 25.4 +/- 16.4 and 2.8 +/- 2.2 vs. 1.1 +/- 1.3, respectively; p < 0.05). Bone scintigraphy did not show a characteristic pattern to differentiate infection from aseptic loosening. The pool phase of the bone scintigraphy was positive in only 3/12 patients with infection (25 %). Sensitivity and specificity of the leukocyte scintigraphy was 83 % and 57 %, respectively. When the results of the bone marrow scintigraphy were added, these values increased to 92 % and 98 %, respectively. CONCLUSION: Performing bone marrow scintigraphy significantly improves results when compared with leukocyte scintigraphy alone in the diagnosis of infected hip prostheses. Bone scintigraphy did not help to differentiate aseptic loosening from infection in this series.


Assuntos
Medula Óssea/diagnóstico por imagem , Fêmur/diagnóstico por imagem , Prótese de Quadril/efeitos adversos , Leucócitos , Osteomielite/diagnóstico por imagem , Infecções Relacionadas à Prótese/diagnóstico por imagem , Compostos Radiofarmacêuticos , Infecções Estafilocócicas/diagnóstico por imagem , Tecnécio Tc 99m Exametazima , Coloide de Enxofre Marcado com Tecnécio Tc 99m , Idoso , Idoso de 80 Anos ou mais , Sedimentação Sanguínea , Proteína C-Reativa/análise , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Osteomielite/etiologia , Falha de Prótese , Cintilografia , Sensibilidade e Especificidade , Infecções Estafilocócicas/etiologia
18.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-28566259

RESUMO

The case involves a 34-year-old woman who underwent surgical removal of a retroperitoneal paraganglioma adjacent to the left kidney's lower pole, previously visualized by CT and MRI. The 123I-MIBG scan was positive for this lesion and, in addition, another uptake was observed located caudally at the level of L5 and of smaller size and less intensity. The second lesion was not considered for surgical removal, due to its lack of morphological definition. One week after surgical intervention, the patient presented difficult-to-control high blood pressure. A second 123I-MIBG scan was performed. The previously described second image was more intense in this study, and surgery was planned to remove it. A combination of techniques including freehand-SPECT and a portable hybrid gamma camera (with optical camera) were used pre-operatively to identify the location of the lesion. The combination of intra-operative laparoscopic gamma probe and portable hybrid gamma camera enabled the tumor to be located, excised, and its complete removal to be monitored. The histopathology analysis confirmed a second paraganglioma.


Assuntos
Imagem Multimodal , Neoplasias Primárias Múltiplas/diagnóstico por imagem , Paraganglioma/diagnóstico por imagem , Radiografia Intervencionista/métodos , Neoplasias Retroperitoneais/diagnóstico por imagem , Cirurgia Assistida por Computador/métodos , 3-Iodobenzilguanidina , Adulto , Desenho de Equipamento , Feminino , Câmaras gama , Humanos , Radioisótopos do Iodo , Imageamento por Ressonância Magnética , Neoplasias Primárias Múltiplas/cirurgia , Paraganglioma/cirurgia , Cintilografia , Neoplasias Retroperitoneais/cirurgia , Tomografia Computadorizada por Raios X
19.
Rev Sci Instrum ; 78(2): 025106, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17578147

RESUMO

A compact minicryostat has been well adapted on the hard x-ray microprobe ID22 of the European Synchrotron Radiation Facility. For variable low-temperature investigations, its special technical design provides precise scanning microscopy and allows easy access for multiple detection modes. Based on x-ray excited optical luminescence technique on the micrometer scale, details of the equipment, its temperature calibration, and typical results are described. Data collections from InAs quantum heterostructures support the excellent thermal performance of the novel cryogenic device.

20.
Nefrologia ; 27(2): 209-13, 2007.
Artigo em Espanhol | MEDLINE | ID: mdl-17564567

RESUMO

Parathyroid carcinoma (PC) is an infrequent disease with a subtle initial presentation and a variable course, necessitating a high index of suspicion to make the correct diagnosis. In chronic failure patients on haemodialysis it becomes even more difficult to suspect this entity since the high prevalence of secondary hyperparathyroidism(SHP). Two patients with PC out of a series of 160 patients with moderate-to-severe SHP submitted for parathyroidectomy are reported. Their clinical features are compared with those of the twenty-two cases previously reported in the literature with a discussion of this pathology. Patients with PC showed higher blood levels of iPTH, total calcium, phosphate and total alkaline phosphatase than the SHP population. The final diagnosis of PC was made after histological study revealing capsular or blood vessel invasion.


Assuntos
Hiperparatireoidismo Secundário/etiologia , Neoplasias das Paratireoides/complicações , Diálise Renal , Adulto , Feminino , Humanos
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