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1.
Trials ; 23(1): 518, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35725616

RESUMO

BACKGROUND: There is a pressing need for scalable healthcare solutions and a shift in the rehabilitation paradigm from hospitals to homes to tackle the increase in stroke incidence while reducing the practical and economic burden for patients, hospitals, and society. Digital health technologies can contribute to addressing this challenge; however, little is known about their effectiveness in at-home settings. In response, we have designed the RGS@home study to investigate the effectiveness, acceptance, and cost of a deep tech solution called the Rehabilitation Gaming System (RGS). RGS is a cloud-based system for delivering AI-enhanced rehabilitation using virtual reality, motion capture, and wearables that can be used in the hospital and at home. The core principles of the brain theory-based RGS intervention are to deliver rehabilitation exercises in the form of embodied, goal-oriented, and task-specific action. METHODS: The RGS@home study is a randomized longitudinal clinical trial designed to assess whether the combination of the RGS intervention with standard care is superior to standard care alone for the functional recovery of stroke patients at the hospital and at home. The study is conducted in collaboration with hospitals in Spain, Sweden, and France and includes inpatients and outpatients at subacute and chronic stages post-stroke. The intervention duration is 3 months with assessment at baseline and after 3, 6, and 12 months. The impact of RGS is evaluated in terms of quality of life measurements, usability, and acceptance using standardized clinical scales, together with health economic analysis. So far, one-third of the patients expected to participate in the study have been recruited (N = 90, mean age 60, days after stroke ≥ 30 days). The trial will end in July 2023. DISCUSSION: We predict an improvement in the patients' recovery, high acceptance, and reduced costs due to a soft landing from the clinic to home rehabilitation. In addition, the data provided will allow us to assess whether the prescription of therapy at home can counteract deterioration and improve quality of life while also identifying new standards for online and remote assessment, diagnostics, and intervention across European hospitals. TRIAL REGISTRATION: C linicalTrials.gov NCT04620707. Registered on November 3, 2020.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Telemedicina , Humanos , Pessoa de Meia-Idade , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/terapia , Reabilitação do Acidente Vascular Cerebral/métodos
3.
iScience ; 24(4): 102364, 2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33997671

RESUMO

The hippocampal formation displays a wide range of physiological responses to different spatial manipulations of the environment. However, very few attempts have been made to identify core computational principles underlying those hippocampal responses. Here, we capitalize on the observation that the entorhinal-hippocampal complex (EHC) forms a closed loop and projects inhibitory signals "countercurrent" to the trisynaptic pathway to build a self-supervised model that learns to reconstruct its own inputs by error backpropagation. The EHC is then abstracted as an autoencoder, with the hidden layers acting as an information bottleneck. With the inputs mimicking the firing activity of lateral and medial entorhinal cells, our model is shown to generate place cells and to respond to environmental manipulations as observed in rodent experiments. Altogether, we propose that the hippocampus builds conjunctive compressed representations of the environment by learning to reconstruct its own entorhinal inputs via gradient descent.

4.
iScience ; 24(5): 102501, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34041451

RESUMO

[This corrects the article DOI: 10.1016/j.isci.2021.102364.].

5.
Trends Cogn Sci ; 25(7): 582-595, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33906817

RESUMO

Biological cognition is based on the ability to autonomously acquire knowledge, or epistemic autonomy. Such self-supervision is largely absent in artificial neural networks (ANN) because they depend on externally set learning criteria. Yet training ANN using error backpropagation has created the current revolution in artificial intelligence, raising the question of whether the epistemic autonomy displayed in biological cognition can be achieved with error backpropagation-based learning. We present evidence suggesting that the entorhinal-hippocampal complex combines epistemic autonomy with error backpropagation. Specifically, we propose that the hippocampus minimizes the error between its input and output signals through a modulatory counter-current inhibitory network. We further discuss the computational emulation of this principle and analyze it in the context of autonomous cognitive systems.


Assuntos
Inteligência Artificial , Redes Neurais de Computação , Algoritmos , Hipocampo , Humanos , Aprendizado de Máquina Supervisionado
7.
Oncol Rep ; 28(4): 1211-6, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22842723

RESUMO

Primary breast mucosa-associated lymphoid tissue (MALT) lymphomas are uncommon and restricted diagnostic criteria should be used to exclude breast involvement by systemic lymphomas. The molecular pathogenesis of primary breast MALT lymphomas is not clear because of the rarity of the disease. Generally the molecular studies of MALT lymphoma in extranodal sites have shown the presence of different chromosomal aberrations, mutually exclusive with substantial differences in their frequency relatively to topographic localization. Few cases of breast MALT lymphomas in the literature have been assessed for MALT lymphoma-associated translocations and BCL10 expression, underlying their rarity in primary breast MALT lymphomas. In our study, we analyzed a series of nine cases of primary breast MALT lymphomas. FISH results showed evidence of MALT1 gene rearrangements in four primary breast lymphomas, in particular three cases with t(11;18)(q21;q21) and one case with t(14;18)(q32;q21). In addition, BCL10 gene rearrangement was not observed. There was no evidence of BCL10 gene translocation in any of the neoplasms assessed. Our data indicate that MALT1 gene rearrangements are not rare in primary breast MALT lymphoma in contrast with results of previous series. Finally, t(11;18) has been observed to be significantly associated with high intensity cytoplasmic BCL10 expression underlying cross-talk between MALT1 and BCL10 pathways in the pathogenesis of MALT lymphomas.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linfoma de Zona Marginal Tipo Células B/genética , Linfoma de Zona Marginal Tipo Células B/patologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteína 10 de Linfoma CCL de Células B , Caspases/genética , Cromossomos Humanos Par 14 , Cromossomos Humanos Par 18 , Feminino , Regulação Neoplásica da Expressão Gênica , Rearranjo Gênico , Humanos , Pessoa de Meia-Idade , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa , Proteínas de Neoplasias/genética , Translocação Genética
8.
Brain Res Bull ; 85(5): 305-12, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21112375

RESUMO

With the advance of novel brain imaging technology more correlations between complex human properties and the neuronal substrate can be assessed. However, thus far, not many well-validated paradigms exist that would allow for a systematic and quantitative exploration of these phenomena. For instance, despite the rapid technological advances in the domain of mixed and virtual reality systems, a fundamental issue remains how we can define and quantify "presence". A standard approach has been to use questionnaires and self-report measures. However, it has been well established that humans' capabilities to access and externalize their internal states are limited. Hence, we have investigated the question whether other less subjective measures can be devised that can corroborate subjective self-reports on presence. In particular, we have developed a quantitative recollection task that assesses the ability of human subjects (N=40) to recollect the factual structure and organization of a structured and fully controlled experience in a human accessible mixed reality space, the eXperience Induction Machine (XIM). In this structured experience - referred to as the "Autodemo"--a virtual guide explains the key elements and properties of XIM while the user is able to freely move around in the space. To evaluate the users' experience and the amount of factual information retained about the Autodemo, we used the ITC-SOPI questionnaire and a recall test specifically designed for the Autodemo. We found significant correlations between spatial presence and engagement factors of ITC-SOPI and recall performance. Moreover we observed an interaction with the participants' gender. Our results show that we can assess correlates of "presence" by focusing on other dependent measures such as those related to memory and performance. Additionally, our work exemplifies how virtual and mixed reality systems provide new ways to address fundamental questions in psychology and cognitive neuroscience.


Assuntos
Relações Interpessoais , Meio Social , Interface Usuário-Computador , Adulto , Feminino , Humanos , Masculino , Inquéritos e Questionários
9.
Int J Surg Pathol ; 18(6): 537-9, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19282295

RESUMO

We report a case of hepatic angiomyolipoma associated to a small bowel schwannoma in a 40-years old woman. Both lesions were asyntomatic. Histologically, hepatic angiomyolipoma showed oncocytic features and scanty adipose tissue, the tumor cells expressed desmin, smooth muscle actin, S-100 protein and HMB45. The tumor cells of intramural small intestinal mass were positive for S-100 protein and GFAP and negative for CD117, CD34 and desmin. To the best of our knowledge, no case of hepatic angiomyolipoma has been previously reported in association with intestinal schwannoma.


Assuntos
Angiomiolipoma/patologia , Neoplasias do Jejuno/patologia , Neoplasias Hepáticas/patologia , Neoplasias Primárias Múltiplas/patologia , Neurilemoma/patologia , Adulto , Angiomiolipoma/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Neoplasias do Jejuno/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Primárias Múltiplas/metabolismo , Neurilemoma/metabolismo
10.
Front Biosci (Elite Ed) ; 2(1): 13-21, 2010 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-20036848

RESUMO

Despite improvements in early diagnosis of uveal melanoma, prognosis is still poor due to metastases development. Neoangiogenesis and migration are requisites to metastasis promotion. Cross-talking between CXCR4-CXCL12 axis and the VEGF pathway was shown to favours tumour progression. CXCR4-CXCL12-VEGF expression was evaluated by immunohistochemistry in 53 selected cases of primary uveal melanoma and in liver melanoma metastases. CXCR4 protein was detected in 41.4 per cent cases, CXCL12 in 43.4 per cent cases and VEGF expression in 39.6 per cent cases. A significant correlation was found between CXCR4 and VEGF expression (p=0.011), CXCL12 and both tumour dimension and (p=0.006) and epithelioid-mixed cytotype (p=0.012). The two cases of uveal melanoma liver metastases in our series showed CXCR4 expression, weak immunoreactivity for CXCL12 and absent VEGF immunostaining. These data indicate that CXCR4-CXCL12 axis and its cross-talking with VEGF plays a role in uveal melanoma metastases and may be new prognostic markers in UMM. Moreover, these results suggest that targeted inhibition of CXCR4 could be introduced to control metastasis development in UMM.


Assuntos
Quimiocina CXCL12/metabolismo , Neoplasias Hepáticas/secundário , Melanoma/metabolismo , Receptores CXCR4/metabolismo , Transdução de Sinais/fisiologia , Neoplasias Uveais/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Primers do DNA/genética , Progressão da Doença , Humanos , Imuno-Histoquímica , Itália , Neoplasias Hepáticas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
11.
Arch Biochem Biophys ; 475(1): 18-24, 2008 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-18423366

RESUMO

Tyramine, an important plant intermediate, was found to be a substrate for two proteins, a copper amine oxidase and a peroxidase from Euphorbia characias latex. The oxidation of tyramine took place by two different mechanisms: oxidative deamination to p-hydroxyphenylacetaldehyde by the amine oxidase and formation of di-tyramine by the peroxidase. The di-tyramine was further oxidized at the two amino groups by the amino oxidase, whereas p-hydroxyphenylacetaldehyde was transformed to di-p-hydroxyphenylacetaldehyde by the peroxidase. Data obtained in this study indicate a new interesting scenario in the metabolism of tyramine.


Assuntos
Amina Oxidase (contendo Cobre)/metabolismo , Euphorbia/enzimologia , Peroxidases/metabolismo , Tiramina/química , Amina Oxidase (contendo Cobre)/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Dimerização , Concentração de Íons de Hidrogênio , Cinética , Estrutura Molecular , Oxirredução , Peroxidases/isolamento & purificação , Espectrofotometria Ultravioleta
12.
FEBS J ; 275(6): 1201-12, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18266763

RESUMO

A class III peroxidase, isolated and characterized from the latex of the perennial Mediterranean shrub Euphorbia characias, contains one ferric iron-protoporphyrin IX pentacoordinated with a histidine 'proximal' ligand as heme prosthetic group. In addition, the purified peroxidase contained 1 mole of endogenous Ca(2+) per mole of enzyme, and in the presence of excess Ca(2+), the catalytic efficiency was enhanced by three orders of magnitude. The incubation of the native enzyme with Ni(2+) causes reversible inhibition, whereas, in the presence of excess Ca(2+), Ni(2+) leads to an increase of the catalytic activity of Euphorbia peroxidase. UV/visible absorption spectra show that the heme iron remains in a quantum mechanically mixed-spin state as in the native enzyme after addition of Ni(2+), and only minor changes in the secondary or tertiary structure of the protein could be detected by fluorescence or CD measurements in the presence of Ni(2+). In the presence of H(2)O(2) and in the absence of a reducing agent, Ni(2+) decreases the catalase-like activity of Euphorbia peroxidase and accelerates another pathway in which the inactive stable species accumulates with a shoulder at 619 nm. Analysis of the kinetic measurements suggests that Ni(2+) affects the H(2)O(2)-binding site and inhibits the formation of compound I. In the presence of excess Ca(2+), Ni(2+) accelerates the reduction of compound I to the native enzyme. The reported results are compatible with the hypothesis that ELP has two Ni(2+)-binding sites with opposite functional effects.


Assuntos
Regulação Alostérica , Euphorbia/enzimologia , Níquel/química , Peroxidases/química , Proteínas de Plantas/química , Cálcio/química , Catálise , Cátions Bivalentes/química , Cátions Bivalentes/metabolismo , Dicroísmo Circular , Fluorescência , Peróxido de Hidrogênio/química , Cinética , Lasers , Níquel/metabolismo , Oxirredução , Peroxidases/antagonistas & inibidores , Peroxidases/metabolismo , Fotólise , Proteínas de Plantas/metabolismo
13.
Biosci Biotechnol Biochem ; 72(1): 29-36, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18175931

RESUMO

The electrochemical behavior of redox centers in the active site of amine oxidases from lentil seedlings and Euphorbia characias latex was investigated using a mercury film electrode. Tyrosine-derived 6-hydroxydopa quinone (TPQ) and copper ions in the active site are redox centers of these amine oxidases. The enzymes undergo two reduction processes at negative potentials related to the reduction of the TPQ cofactor to the corresponding hydroquinones and the reduction of copper ions, (Cu(II)-->Cu(I)). Copper depleted enzymes, prepared by reduction with dithionite followed by dialysis against cyanide, undergo only one reduction process. Nyquist diagrams, recorded at potentials corresponding to the reduction of cofactors as dc-offset, represent charge transfer impedance followed by a Warburg-type line at low frequencies, indicating the occurrence of a diffusion controlled process in the rate-limiting step of the reduction process.


Assuntos
Amina Oxidase (contendo Cobre)/metabolismo , Euphorbia/enzimologia , Lens (Planta)/enzimologia , Plântula/enzimologia , Amina Oxidase (contendo Cobre)/química , Aminoácido Oxirredutases/química , Aminoácido Oxirredutases/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Cobre/metabolismo , Di-Hidroxifenilalanina/análogos & derivados , Di-Hidroxifenilalanina/análise , Eletroquímica , Eletrodos , Cinética , Dados de Sequência Molecular , Oxirredução , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo
14.
Ann Surg Oncol ; 15(1): 69-79, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17896140

RESUMO

BACKGROUND: Unlike other human tumors, gastric cancer remains a great therapeutic challenge since no standardized postoperative treatment exists. Knowledge of molecular pathways determining the behavior of individual gastric tumors seems to be crucial for therapeutic decisions, and evaluation of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) expression might be critical for prognosis, assessment, and identification of patients that could be treated with tailored therapies. METHODS: VEGF and EGFR determination was performed in 88 gastric cancer samples as well as 25 normal gastric mucosa specimens from non-cancer patients using a commercially available immunohistochemistry kit. In all samples, the correlation of VEGF and EGFR expression was investigated with each other, and with other prognostic indicators in all samples, and, finally, with survival rates in 69 patients undergoing potentially curative surgery. RESULTS: Forty-eight per cent (42 cases) of gastric cancers expressed VEGF, and 44% (39 cases) stained for EGFR. In curatively treated patients, VEGF and EGFR expression was demonstrated to correlate with worse survival in both univariate and multivariate analyses. Molecular profiling was shown to more accurately estimate the risk of cancer-related death than TNM stage, and, of most interest, to allow sorting out high-risk patients within the same stage. CONCLUSIONS: These findings provide evidence that contemporary evaluation of VEGF and EGFR expression may be crucial to select gastric cancer patients with poor prognosis who may benefit of tailored treatments.


Assuntos
Receptores ErbB/metabolismo , Recidiva Local de Neoplasia/metabolismo , Neoplasias Gástricas/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais , Feminino , Humanos , Técnicas Imunoenzimáticas , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Prognóstico , Neoplasias Gástricas/patologia , Resultado do Tratamento
15.
Biosci Biotechnol Biochem ; 71(7): 1644-9, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17617729

RESUMO

The relationships between the structural and energetic domains of lentil seedling amine oxidase (LSAO) were investigated using modifiers that target the active site and the carbohydrate moiety of the enzyme. An irreversible inhibitor, aminoguanidine, specifically modified the active site of the lentil enzyme, whereas sodium metaperiodate cleaves carbohydrate moieties covalently bound to the native enzyme. Differential scanning calorimetry (DSC) measurements were made on the modified LSAOs. Deconvolution of the reversible thermal DSC profiles of the modified enzyme gave three subpeaks (energetic domains), each of which was assigned to one of the three structural domains of the native protein. Our results led us to conclude that deglycosylation of LSAO has no effect on thermal stability, whereas binding of the inhibitor imparts more stability to the enzyme.


Assuntos
Amina Oxidase (contendo Cobre)/química , Lens (Planta)/enzimologia , Plântula/enzimologia , Varredura Diferencial de Calorimetria , Desnaturação Proteica , Estrutura Terciária de Proteína
16.
Onkologie ; 30(6): 324-6, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17551257

RESUMO

BACKGROUND: Unusual sites of metastasis to the parotid gland and face are reported in patients with colorectal cancer, but the localization to both sites at the same time has never been described so far. CASE REPORT: Here, we describe the case of a 76-year-old woman with a T3N1M0 G2 rectal adenocarcinoma, treated with preoperative chemoradiotherapy performed at suboptimal dosages due to unacceptable toxicity. At the end of the program, the re-staging demonstrated the presence of metastasis in both the left parotid gland and subcutaneously on the frontal region of her face while the primary locoregional tumour manifestation was radiologically down-staged (reduction in N staging from N1 to N0). The patient did not respond to any other treatment and died due to disease progression 15 months after the diagnosis. CONCLUSIONS: Metastatic tumours in the parotid gland are uncommon with a higher incidence of primary sites of the head and neck. Parotid involvement of rectal adenocarcinoma is also extremely rare, and concomitant involvement of both the parotid gland and the face was not previously described. In this case, we cannot rule out the hypothesis that the delay of surgical removal of the primary tumour and/or a specific action of concomitant chemoradiotherapy on the tumour cell phenotype could promote cancer cell spreading to unusual sites.


Assuntos
Adenocarcinoma/secundário , Neoplasias Faciais/secundário , Terapia Neoadjuvante , Neoplasias Parotídeas/secundário , Neoplasias Retais/terapia , Neoplasias Cutâneas/secundário , Adenocarcinoma/patologia , Adenocarcinoma/terapia , Idoso , Biópsia , Terapia Combinada , Progressão da Doença , Neoplasias Faciais/patologia , Feminino , Seguimentos , Humanos , Estadiamento de Neoplasias , Neoplasias Parotídeas/patologia , Proctoscopia , Neoplasias Retais/patologia , Reto/patologia , Neoplasias Cutâneas/patologia
17.
World J Surg ; 31(7): 1458-68, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17516110

RESUMO

BACKGROUND: In gastric cancer, the recurrence rate is high even after curative surgery. A relevant issue is the identification of independent prognostic factors to select high-risk patients; such features can be used as predictive factors for tailored therapies. In this study we have investigated the role of epidermal growth factor receptor (EGFR) expression as a prognostic marker for predicting cancer behavior and clinical outcome in gastric cancer patients undergoing potentially curative surgery. METHODS: Epidermal growth factor receptor determination using a commercially available immunohistochemistry (IHC) kit was performed in tissues from 82 gastric cancer patients receiving primary surgical treatment and in 25 normal gastric mucosa specimens from noncancer patients. The EGFR positivity was correlated with disease recurrence and survival in univariate and multivariate analyses. RESULTS: Forty-four percent (36 cases) of gastric cancers were EGFR positive. In 66 curatively treated patients, EGFR expression correlated with disease recurrence and poorer survival in both univariate and multivariate analyses. In a multivariate model for predicting recurrence and survival, advanced tumor extension (T(3) or T(4)), nodal metastases, and EGFR expression were the only independent covariates. In particular, EGFR expression was shown to be a significant predictor of poor prognosis among gastric cancer patients having the same stage according to the current TNM staging system. CONCLUSIONS: These findings suggest that EGFR expression may be useful in identifying high-risk gastric cancer patients undergoing potentially curative surgery. Multimodal treatments should be considered in the adjuvant treatment of these patients.


Assuntos
Receptores ErbB/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Fundo Gástrico , Humanos , Imuno-Histoquímica , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Antro Pilórico , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia
18.
Ital J Biochem ; 56(1): 1-5, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17511348

RESUMO

A new procedure to purify to homogeneity an Euphorbia characias latex peroxidase is performed employing a calmodulin-Sepharose column as affinity chromatography. The advantage of this approach is the isolation of a peroxidase under fast and mild elution conditions with a high recovery in total activity.


Assuntos
Cromatografia de Afinidade/métodos , Peroxidase/isolamento & purificação , Amina Oxidase (contendo Cobre)/isolamento & purificação , Sequência de Aminoácidos , Calmodulina/química , Euphorbia/enzimologia , Látex/química , Dados de Sequência Molecular , Sefarose
19.
FEBS J ; 274(10): 2585-95, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17433047

RESUMO

The interaction of xenon with copper/6-hydroxydopa (2,4,5-trihydroxyphenethylamine) quinone (TPQ) amine oxidases from the plant pulses lentil (Lens esculenta) and pea (Pisum sativum) (seedlings), the perennial Mediterranean shrub Euphorbia characias (latex), and the mammals cattle (serum) and pigs (kidney), were investigated by NMR and optical spectroscopy of the aqueous solutions of the enzymes. (129)Xe chemical shift provided evidence of xenon binding to one or more cavities of all these enzymes, and optical spectroscopy showed that under 10 atm of xenon gas, and in the absence of a substrate, the plant enzyme cofactor (TPQ), is converted into its reduced semiquinolamine radical. The kinetic parameters of the analyzed plant amine oxidases showed that the k(c) value of the xenon-treated enzymes was reduced by 40%. Moreover, whereas the measured K(m) value for oxygen and for the aromatic monoamine benzylamine was shown to be unchanged, the K(m) value for the diamine putrescine increased remarkably after the addition of xenon. Under the same experimental conditions, the TPQ of bovine serum amine oxidase maintained its oxidized form, whereas in pig kidney, the reduced aminoquinol species was formed without the radical species. Moreover the k(c) value of the xenon-treated pig enzyme in the presence of both benzylamine and cadaverine was shown to be dramatically reduced. It is proposed that the lysine residue at the active site of amine oxidase could be involved both in the formation of the reduced TPQ and in controlling catalytic activity.


Assuntos
Amina Oxidase (contendo Cobre)/química , Lisina/química , Amina Oxidase (contendo Cobre)/antagonistas & inibidores , Amina Oxidase (contendo Cobre)/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Bovinos , Di-Hidroxifenilalanina/análogos & derivados , Di-Hidroxifenilalanina/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Euphorbia/enzimologia , Rim/enzimologia , Cinética , Lens (Planta)/enzimologia , Ressonância Magnética Nuclear Biomolecular , Pisum sativum/enzimologia , Alinhamento de Sequência , Suínos , Isótopos de Xenônio
20.
Cancer Immunol Immunother ; 56(10): 1589-95, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17410362

RESUMO

PURPOSE: Although relatively rare, uveal melanoma is the most common ocular tumor of adults. Up to half of uveal melanoma patients die of metastatic disease. CXCR4, a chemokine receptor, is a prognostic factor in cutaneous melanoma involved in angiogenesis and metastasis formation. The aim of this study was to evaluate the expression of CXCR4 in uveal melanoma. METHODS: CXCR4 was detected by immunohistochemistry in 44 samples of uveal melanoma. Staining was categorized into three semiquantitative classes based on the rate of stained (positive) tumor cells: absence of staining, <50% of cell (+) and >50% (++). Correlations between CXCR4 expression, data on patient and tumor features were studied by contingency tables and the chi2 test. Time-to-event curves were studied using the Kaplan-Meier method. Univariate analysis was performed using the log-rank test. Ninety-five percent confidence intervals (95% CI) of hazard ratios were also reported. RESULTS: Staining for CXCR4 protein was absent in 18 tumors (40.9%), present in <50% of cells in 19 (43.2%) and in >50% of cells in 7 (15.9%) tumors. CXCR4 expression correlated to the epithelioid-mixed cell type (P=0.030). No statistically significant relation emerged between CXCR4 expression, largest tumor diameter (LTD) and extracellular matrix patterns as evaluated through histological patterns stained with periodic acid-Schiff (PAS). Events occurred in 2 out of 18 patients (11.1%) with negative tumors (2 deaths), in 3 out of 19 patients (15.8%) with <50% of positive tumor cells (2 deaths and 1 occurrence of metastases) and in 1 out of 7 patients (14.3%) with >50% of positive tumor cells (1 occurrence of metastases). The cell type (P=0.0457) but not CXCR4 showed prognostic value at univariate analysis. CONCLUSION: This study shows that CXCR4 is commonly expressed in uveal melanoma and correlates with cell type a well-established prognostic factor.


Assuntos
Biomarcadores Tumorais/análise , Melanoma/diagnóstico , Receptores CXCR4/análise , Neoplasias Uveais/diagnóstico , Feminino , Humanos , Imuno-Histoquímica , Masculino , Melanoma/patologia , Prognóstico , Neoplasias Uveais/patologia
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