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1.
Rev Sci Instrum ; 94(9)2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37655988

RESUMO

The Ma_MISS miniaturized spectrometer is integrated within the Drilling System of the ExoMars Rosalind Franklin Rover for Mars exploration. Here we focus on the on ground calibration campaign to obtain radiometric and linearity calibrations of the Ma_MISS instrument, while the first paper dealt with the spectral calibration [De Angelis et al., Rev. Sci. Instrum. 93, 123704 (2022)]. The experimental setup used to carry out radiometric calibration is described, as are the methods used for data processing and key parameter retrieval. In particular, the Spectrometer Transfer Function (Responsivity), Signal-to-Noise Ratio, and detector linearity are determined. In a third paper [De Sanctis et al., Planet. Sci. J. 3, 142 (2022)], validation of the Ma_MISS calibration results through spectral measurements performed on rock and synthetic targets during the radiometric calibration campaign is described.

2.
Cleft Palate Craniofac J ; 60(12): 1591-1599, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-35786009

RESUMO

OBJECTIVE: To investigate the relationship between perception of craniofacial deformity, geometric head features, and 3D head shape analyzed by statistical shape modeling (SSM). PATIENTS: A total of 18 unoperated patients with scaphocephaly (age = 5.2 ± 1.1m)-6 were followed-up after spring-assisted cranioplasty (SAC) (age = 9.6 ± 1.5m)-and 6 controls (age = 6.7 ± 2.5m). MAIN OUTCOME MEASURES: 3D head shapes were retrieved from 3D scans or computed tomography (CTs). Various geometrical features were measured: anterior and posterior prominence, take-off angle, average anterior and posterior lateral and horizontal curvatures, cranial index (CI) (cranial width over length), and turricephaly index (TI) (cranial height over length). SSM and principal component analysis (PCA) described shape variability. All models were 3D printed; the perception of deformity was blindly scored by 9 surgeons and 1 radiologist in terms of frontal bossing (FB), occipital bulleting (OB), biparietal narrowing (BN), low posterior vertex (LPV), and overall head shape (OHS). RESULTS: A moderate correlation was found between FB and anterior prominence (r = 0.56, P < .01) and take-off angle (r = - 0.57, P < .01). OB correlated with average posterior lateral curvature (r = 0.43, P < 0.01) similarly to BPN (r = 0.55, P < .01) and LPV (r = 0.43, P < .01). OHS showed strong correlation with CI (r = - 0.68, P < .01) and TI (r = 0.63, P< .01). SSM Mode 1 correlated with OHS (r = 0.66, p < .01) while Mode 3 correlated with FB (r = - 0.58, P < .01). CONCLUSIONS: Esthetic cranial appearance in craniofacial patients is correlated to specific geometric parameters and could be estimated using automated methods such as SSM.


Assuntos
Craniossinostoses , Anormalidades Maxilomandibulares , Humanos , Pré-Escolar , Criança , Cefalometria/métodos , Craniossinostoses/diagnóstico por imagem , Craniossinostoses/cirurgia , Crânio/cirurgia , Percepção , Estética
3.
Rev Sci Instrum ; 93(12): 123704, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36586927

RESUMO

The Ma_MISS spectrometer is integrated within the drilling system of the Rosalind Franklin ExoMars rover. This paper reports the on-ground calibration campaign performed on the spectrometer. Here, we focus on the spectral calibration of the instrument. The experimental setup used to carry out calibration is described, and the methods used for data processing and key parameters retrieval are explained. In particular, the spectral parameters such as (i) pixel central wavelengths, (ii) spectral response function, (iii) spectral resolution, (iv) sampling, and (v) range are determined. In a follow-up paper, the linearity and radiometric calibrations are described, while in De Sanctis et al. [Planet. Sci. J. 3, 142 (2022)], the validation of spectral measurements performed on synthetic and natural rock targets is presented.

4.
Int J Comput Assist Radiol Surg ; 17(1): 55-64, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34533757

RESUMO

PURPOSE: Sliding genioplasty is used to surgically correct a retruded or misaligned chin: in this procedure, an osteotomy is performed and the bony segment is repositioned. In this study we investigate the effect of surgical parameters (bony segment movement, osteotomy design) on postop soft tissue changes in a patient cohort. METHODS: Seven patients were retrospectively recruited. Cone beam computed tomography data were obtained and soft tissue and bone shape reconstructions were performed. 3D models were created and surgical cuts were replicated according to postop scans. Each model was imported in ANSYS 2019R1 (Ansys Inc, USA) for simulation: the effect of variation in osteotomy plane as well as extent of bony segment movement were assessed by means of design of experiment: surgical parameters were varied in a surgically acceptable range and the soft tissue predictions were evaluated as displacement output of five craniometric landmarks. RESULTS: Simulation results show the overall changes of the lower third of the face are sensitive to changes in horizontal and vertical displacement of the bony segment as well as segment rotation. No significant changes in the soft tissue response were to attribute to the osteotomy design. CONCLUSIONS: Our results are consistent with experimental findings reported in the literature: when planning genioplasty in orthognathic surgery, particular focus on the segment movement (horizontal translation, vertical translation and rotation), rather than on the design of the osteotomy itself, should be considered.


Assuntos
Mentoplastia , Procedimentos Cirúrgicos Ortognáticos , Cefalometria , Humanos , Mandíbula , Estudos Retrospectivos
5.
J Laryngol Otol ; 134(7): 571-576, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32605666

RESUMO

BACKGROUND: An objective evaluation of coronavirus disease 2019 in the first days of infection is almost impossible, as affected individuals are generally in home quarantine, and there is limited accessibility for the operator who should perform the test. To overcome this limitation, a recently validated psychophysical self-administered test was used, which can be performed remotely in the assessment of early-stage coronavirus disease 2019 patients. METHODS: Olfactory and gustatory functions were objectively assessed in 300 patients in the first 7 days from coronavirus disease 2019 symptom onset. RESULTS: Seventy per cent of the patients presented olfactory and/or gustatory disorders. The dysfunctions detected were mainly complete anosmia (47 per cent) or ageusia (38 per cent). A significant correlation was found between taste dysfunction and female gender (odds ratio = 1.936, p = 0.014) and fever (odds ratio = 2.132, p = 0.003). CONCLUSION: The psychophysical evaluation protocol proposed is an effective tool for the fast and objective evaluation of patients in the early stages of coronavirus disease 2019. Chemosensitive disorders have been confirmed to be frequent and early symptoms of the coronavirus infection, and, in a significant number of cases, they are the first or only manifestation of coronavirus disease 2019.


Assuntos
Infecções por Coronavirus/fisiopatologia , Autoavaliação Diagnóstica , Técnicas e Procedimentos Diagnósticos , Transtornos do Olfato/diagnóstico , Pneumonia Viral/fisiopatologia , Distúrbios do Paladar/diagnóstico , Telemedicina , Ácido Acético , Adulto , Betacoronavirus , COVID-19 , Chocolate , Café , Combinação de Medicamentos , Feminino , Sucos de Frutas e Vegetais , Produtos Domésticos , Humanos , Itália , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Antissépticos Bucais , Transtornos do Olfato/fisiopatologia , Pandemias , Extratos Vegetais , SARS-CoV-2 , Autorrelato , Limiar Sensorial , Fatores Sexuais , Sabões , Especiarias , Distúrbios do Paladar/fisiopatologia , Limiar Gustativo , Terpenos , Cremes Dentais , Vinho
6.
J Biol Regul Homeost Agents ; 32(2 Suppl. 1): 179-183, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29460538

RESUMO

Endocarditis is a cardiovascular disease caused by the inflammation of the inner tissues of the heart, the endocardium, usually of the valves. Bacteraemia is essential in the development of endocarditis, and there are some findings that the main pathogens of endocarditis are viridans group streptococci: Streptococcus oralis, Streptococcus sanguinis, and Enterococcus faecalis. There is strong evidence that endocarditis bacteria are present in the tonsillar microbiota, so that tonsillar infection is associated with an increased risk of endocarditis. The aim of this manuscript is to investigate the presence of the main pathogens of endocarditis in tonsillar microbiota of an Afghan population group. A sample of 80 tonsil swabs were analyzed by quantitative real time PCR to detect endocarditis pathogens and an estimation of the total bacterial load. The median bacterial load in PCR reaction was 1.4x106 (interquartile range 4,7x105 - 2,9x106). Three species, S. Oralis, S. Sanguinis, and E. Faecalis were found in large amounts in all specimens. On the other hand, S. Mitis was never detected. The S. Aureus was found in 3 samples with a prevalence of 0.04 (C.I. 0.01-0.10). The S. Mutans was found in 33 samples with a prevalence of 0.41 (C.I. 0.31-0.52). Endocarditis bacteria has been found into the tonsillar microbiota, so there is sufficient evidence to justify that the oral cavity is a reservoir of endocarditis bacteria that can have a significant impact on the cardiovascular function.


Assuntos
Bactérias/isolamento & purificação , Endocardite/microbiologia , Mucosa/microbiologia , Tonsila Palatina/microbiologia , Afeganistão/epidemiologia , Humanos , Staphylococcus aureus/isolamento & purificação
7.
J Biol Regul Homeost Agents ; 32(2 Suppl. 1): 185-190, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29460539

RESUMO

Some studies have evidenced the role of human polyomaviruses in head and neck squamous cell carcinoma. BK, JC and SV40 human polyoma viruses are widely recognized as etiological agents associated with malignancies. The aim of this study was to analyse the prevalence of BK, IC and SV40 in tonsillar microbiota in a group of Afghan volunteers. A sample of the tonsillar microbiota was taken from a single site using a sterile oral swab paper stick. A fixed volume of purified DNA from each sample was tested by quantitative real-time polymerase chain reactions to evaluate the number of human cells and the number of viral genomes in each sample. The cell number was evaluated via the quantification of a single copy genomic sequence, which is located in the HMBS locus. The median analyzed cell number in each reaction was 4343 (interquartile range 2074-8470). SV40 was never detected, while prevalence rate was 0.11 (C.I. 0.06-0.20) for BK and 0.10 (C.I. 0.05-0.19) for JC. Further studies are necessary to clarify whether polyomaviruses can be considered a risk factor of oral, oropharyngeal and laryngeal malignancies.


Assuntos
Tonsila Palatina/microbiologia , Polyomavirus/isolamento & purificação , Afeganistão/epidemiologia , Humanos , Infecções por Polyomavirus/epidemiologia , Infecções por Polyomavirus/microbiologia , Prevalência , Vírus 40 dos Símios/isolamento & purificação
8.
J Biol Regul Homeost Agents ; 32(2 Suppl. 1): 191-196, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29460540

RESUMO

Cancer of the oral cavity is known to have a diverse aetiology that includes infectious agents. Human papilloma virus has been found to be associated with several types of human cancer, inclusive of cervical, vulvar, vaginal, penile, anal, and cancer of tonsil. The aim of this manuscript is to investigate the presence of human papilloma virus in tonsillar microbiota of an Afghan population group. A sample of the tonsillar microbiota was collected by oral swab paper stick from 80 healthy donors. The sample was investigated for the presence of high-risk human papillomavirus types 16, 18, 31 and 45 by real time PCR. Eight samples produced some positive endpoint signals for human papillomaviruses. The human papillomavirus 31 was the unique papillomavirus detected; its calculated prevalence rate was 0.10 (C.I. 0.05-0.19). However, the viral load was always very low, in the order of 10-3 viral genomes per cell. The high prevalence of high-risk human papillomavirus in healthy population suggest a need for further investigation on virus spreading and supports the development of vaccination strategies.


Assuntos
Microbiota , Tonsila Palatina/microbiologia , Polyomavirus/isolamento & purificação , Afeganistão/epidemiologia , Feminino , Humanos , Masculino , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/microbiologia , Polyomavirus/classificação , Polyomavirus/genética , Infecções por Polyomavirus/epidemiologia , Infecções por Polyomavirus/microbiologia , Prevalência
9.
Biomech Model Mechanobiol ; 16(4): 1459-1473, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28357604

RESUMO

The affine transformation hypothesis is usually adopted in order to link the tissue scale with the fibers scale in structural constitutive models of fibrous tissues. Thanks to the recent advances in imaging techniques, such as multiphoton microscopy, the microstructural behavior and kinematics of fibrous tissues can now be monitored at different stretching within the same sample. Therefore, the validity of the affine hypothesis can be investigated. In this paper, the fiber reorientation predicted by the affine assumption is compared to experimental data obtained during mechanical tests on skin and liver capsule coupled with microstructural imaging using multiphoton microscopy. The values of local strains and the collagen fibers orientation measured at increasing loading levels are used to compute a theoretical estimation of the affine reorientation of collagen fibers. The experimentally measured reorientation of collagen fibers during loading could not be successfully reproduced with this simple affine model. It suggests that other phenomena occur in the stretching process of planar fibrous connective tissues, which should be included in structural constitutive modeling approaches.


Assuntos
Colágeno/fisiologia , Modelos Biológicos , Fenômenos Biomecânicos , Humanos , Fígado/citologia , Fígado/metabolismo , Pele/citologia , Pele/metabolismo , Estresse Mecânico
10.
Minerva Cardioangiol ; 59(2): 135-8, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21368733

RESUMO

AIM: Early recurrence of atrial fibrillation (AF) is common after electrical cardioversion (ECV). Accurate prediction of AF recurrence might allow more selective use of ECV and the targeted use of antiarrhtyhmic therapy in those at highest risk of recurrence. METHODS: We have screened consecutive patients attending for cardioversion of AF and recruited those without valvular heart disease, heart failure or permanent pacemakers. All patients underwent echocardiography and measurement of serum BNP levels within 24 hours before ECV. Measurement of BNP was repeated at 1, 7, 30 and 90 days after ECV and an ECG recorded on each occasion. RESULTS: We have screened 24 consecutive patients. Five were excluded. All 19 study subjects were succesfully cardioverted to sinus rhythm. AF recurred in nine cases. Recurrence of AF was associated with AF duration, left atrial size, the presence of hypertension and the BNP level before cardioversion. BNP fell significantly after cardioversion. The BNP level after cardioversion was not associated with AF recurrence. CONCLUSION: Even in persons without valvular heart disease or heart failure, an elevated level of BNP predicts recurrence of AF after ECV. The level to which BNP falls after cardioversion is not predictive of AF recurrence.


Assuntos
Fibrilação Atrial/sangue , Fibrilação Atrial/terapia , Cardioversão Elétrica , Peptídeo Natriurético Encefálico/sangue , Idoso , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Estudos Prospectivos , Recidiva
11.
Free Radic Biol Med ; 50(3): 477-83, 2011 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-21130864

RESUMO

In vivo hyperoxic preconditioning (PC) has been shown to protect against ischemia/reperfusion (I/R) myocardial damage. Mitochondrial permeability transition pore (MPTP) opening is an important event in cardiomyocyte cell death occurring during I/R and therefore a possible target for cardioprotection. We tested the hypothesis that in vivo hyperoxic PC, obtained by mechanical ventilation of animals, could protect heart against I/R injury by inhibiting MPTP opening and cytochrome c release from mitochondria. Mechanically ventilated rats were first exposed to a short period of hyperoxia and isolated hearts were subsequently subjected to I/R in a Langendorff apparatus. Hyperoxic PC significantly improved the functional recovery of hearts on reperfusion, reduced the infarct size, and decreased necrotic damage as shown by the reduced release of lactate dehydrogenase. Mitochondria from hyperoxic PC hearts were less sensitive than mitochondria from reperfused heart to MPTP opening. In addition, hyperoxic PC prevented mitochondrial NAD(+) depletion, an indicator of MPTP opening, and cytochrome c release as well as cardiolipin oxidation/depletion associated with I/R. Together, these results demonstrate that hyperoxic PC protects against heart I/R injury by inhibiting MPTP opening and cytochrome c release. Thus, in vivo hyperoxic PC may represent a useful strategy for the treatment of cardiac I/R injury and could have potential applications in clinical practice.


Assuntos
Citocromos c/metabolismo , Hiperóxia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/metabolismo , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miocárdio/patologia , Animais , Cálcio/metabolismo , Cardiolipinas/metabolismo , Masculino , Poro de Transição de Permeabilidade Mitocondrial , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/metabolismo , NAD/metabolismo , Necrose , Oxigênio/farmacologia , Ratos , Ratos Wistar
12.
Neurochem Int ; 53(5): 126-31, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18657582

RESUMO

Reactive oxygen species (ROS) are considered a key factor in brain aging process. Mitochondrial respiration is an important site of ROS production and hence a potential contributor to brain functional changes with aging. In this study we examined the effect of aging on complex I activity, oxygen consumption, ROS production and phospholipid composition in rat brain mitochondria. The activity of complex I was reduced by 30% in brain mitochondria from 24 months aged rats relative to young animals. These changes in complex I activity were associated with parallel changes in state 3 respiration. H(2)O(2) generation was significantly increased in mitochondria isolated from aged rats. The mitochondrial content of cardiolipin, a phospholipid required for optimal activity of complex I, decreased by 31% as function of aging, while there was a significant increase in the level of peroxidized cardiolipin. The age-related decrease in complex I activity in brain mitochondria could be reversed by exogenously added cardiolipin. This effect of cardiolipin could not be replaced by other phospholipids. It is proposed that aging causes brain mitochondrial complex I dysfunction which can be attributed to ROS-induced cardiolipin oxidation. These findings may prove useful in elucidating the mechanism underlying mitochondrial dysfunction associated with brain aging.


Assuntos
Envelhecimento/metabolismo , Encéfalo/metabolismo , Cardiolipinas/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Técnicas In Vitro , Masculino , Oxirredução , Ratos , Ratos Wistar
13.
J Biomater Sci Polym Ed ; 18(12): 1527-45, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17988518

RESUMO

In this study, a highly porous collagen-based biodegradable scaffold was developed as an alternative to synthetic, non-degradable corneal implants. The developed method involved lyophilization and subsequent stabilization through N-ethyl-N'-[3-dimethylaminopropyl] carbodiimide/N-hydroxy succinimide (EDC/NHS) cross-linking to yield longer lasting, porous scaffolds with a thickness similar to that of native cornea (500 microm). For collagen-based scaffolds, cross-linking is essential; however, it has direct effects on physical characteristics crucial for optimum cell behavior. Hence, the effect of cross-linking was studied by examining the influence of cross-linking on pore size distribution, bulk porosity and average pore size. After seeding the foam with human corneal keratocytes, cell proliferation, cell penetration into the scaffold and ECM production within the scaffold were studied. After a month of culture microscopical and immunohistochemical examinations showed that the foam structure did not undergo any significant loss of integrity, and the human corneal keratocytes populated the scaffold with cells migrating both longitudinally and laterally, and secreted some of the main constituents of the corneal ECM, namely collagen types I, V and VI. The foams had a layer of lower porosity (skin layer) both at the top and the bottom. Foams had an optimal porosity (93.6%), average pore size (67.7 microm), and chemistry for cell attachment and proliferation. They also had a sufficiently rapid degradation rate (73.6+/-1.1% in 4 weeks) and could be produced at a thickness close to that of the natural corneal stroma. Cells were seeded at the top surface of the foams and their numbers there was higher than the rest, basically due to the presence of the skin layer. This is considered to be an advantage when epithelial cells need to be seeded for the construction of hemi or full thickness cornea.


Assuntos
Carbodi-Imidas/química , Colágeno Tipo I/química , Substância Própria , Reagentes de Ligações Cruzadas/química , Próteses e Implantes , Succinimidas/química , Engenharia Tecidual/métodos , Proliferação de Células , Células Cultivadas , Humanos , Imuno-Histoquímica , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência
14.
FASEB J ; 20(2): 269-76, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16449799

RESUMO

Reactive oxygen species (ROS) are considered an important factor in ischemia/reperfusion injury to cardiac myocytes. Mitochondrial respiration, mainly at the level of complex I and III, is an important source of ROS generation and hence a potential contributor of cardiac reperfusion injury. Appropriate antioxidant strategies could be particularly useful to limit this ROS generation and associated mitochondrial dysfunction. Melatonin has been shown to effectively protect against ischemic-reperfusion myocardial damage. The mechanism by which melatonin exerts this cardioprotective effect is not well established. In the present study we examined the effects of melatonin on various parameters of mitochondrial bioenergetics in a Langerdoff isolated perfused rat heart model. After isolation of mitochondria from control, ischemic-reperfused and melatonin-treated ischemic-reperfused rat heart, various bioenergetic parameters were evaluated such as rates of mitochondrial oxygen consumption, complex I and complex III activity, H2O2 production as well as the degree of lipid peroxidation, cardiolipin content, and cardiolipin oxidation. We found that reperfusion significantly altered all these mitochondrial parameters, while melatonin treatment had strong protective effect attenuating these alterations. This effect appears to be due, at least in part, to the preservation, by ROS attack, of the content and integrity of cardiolipin molecules which play a pivotal role in mitochondrial bioenergetics. Protection of mitochondrial dysfunction was associated with an improvement of post-ischemic hemodynamic function of the heart. Melatonin had also strong protective effect against oxidative alterations to complex I and III as well as to cardiolipin in isolated mitochondria.


Assuntos
Cardiolipinas/metabolismo , Coração/efeitos dos fármacos , Melatonina/farmacologia , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/fisiologia , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Animais , Masculino , Mitocôndrias Cardíacas/metabolismo , Consumo de Oxigênio , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo
15.
Biochim Biophys Acta ; 1710(2-3): 78-86, 2005 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-16325647

RESUMO

Reactive oxygen species (ROS) are considered an important factor in ischemia/reperfusion injury to cardiac myocites. Mitochondrial respiration is an important source of ROS generation and hence a potential contributor to cardiac reperfusion injury. Appropriate treatment strategy could be particularly useful to limit this ROS generation and associated mitochondrial dysfunction. In the present study, we examined the effect of lowering the oxygen tension, at the onset of the reperfusion, on various parameters of mitochondrial bioenergetics in rat heart tissue. After isolation of mitochondria from control, ischemic, normoxic and hypoxic reperfused rat heart, various bioenergetic parameters were evaluated such as rates of mitochondrial oxygen consumption, complex I and complex III activity, H2O2 production and in addition, the degree of lipid peroxidation, cardiolipin content and cardiolipin oxidation. We found that normoxic reperfusion significantly altered all these mitochondrial parameters, while hypoxic reperfusion had a protective effect attenuating these alterations. This effect appears to be due, at least in part, to a reduction of mitochondrial ROS generation with subsequent preservation of cardiolipin integrity, protection of mitochondrial function and improvement of post-ischemic hemodynamic function of the heart.


Assuntos
Cardiolipinas/metabolismo , Mitocôndrias Cardíacas/metabolismo , Traumatismo por Reperfusão Miocárdica/metabolismo , Reperfusão Miocárdica , Espécies Reativas de Oxigênio/metabolismo , Animais , Cardiolipinas/fisiologia , Complexo I de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Radicais Livres/metabolismo , Peróxido de Hidrogênio , Peroxidação de Lipídeos , Mitocôndrias Cardíacas/enzimologia , Traumatismo por Reperfusão Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/terapia , Oxirredução , Oxigênio/metabolismo , Consumo de Oxigênio , Ratos
16.
FEBS Lett ; 515(1-3): 114-8, 2002 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-11943205

RESUMO

Potential contamination of animal-derived collagen with pathogens has led to the demand for safe recombinant sources of this complex molecule. In continuation of our previous work [Ruggiero et al. (2000) FEBS Lett. 469, 132-136], here we show that it is possible to produce recombinant hydroxylated homotrimeric collagen in tobacco plants that are co-transformed with a human type I collagen and a chimeric proline-4-hydroxylase (P4H). This is to our knowledge the first time that transient expression in tobacco was used to improve the quality of a recombinant protein produced in plants through co-expression with an animal cell-derived modifying enzyme. We demonstrated the functionality of the new chimeric P4H and thus improved the thermal stability of recombinant collagen I from plants to 37 degrees C.


Assuntos
Agrobacterium tumefaciens/metabolismo , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Aminoácidos/análise , Bioensaio , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Colágeno Tipo I/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Expressão Gênica , Humanos , Hidroxilação , Pepsina A/química , Plantas Geneticamente Modificadas , Pró-Colágeno-Prolina Dioxigenase/genética , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Conformação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Temperatura , Nicotiana/química , Transformação Genética
17.
FEBS Lett ; 509(3): 435-8, 2001 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-11749969

RESUMO

Cytochrome c release from mitochondria is a critical event in the apoptosis induction. Dissociation of cytochrome c from the mitochondrial inner membrane (IMM) is a necessary first step for cytochrome c release. In the present study, the effect of reactive oxygen species (ROS) on the dissociation of cytochrome c from beef-heart submitochondrial particles (SMP) and on the cardiolipin content was investigated. Exposure of SMP to mitochondrial-mediated ROS generation resulted in a large dissociation of cytochrome c from SMP and in a parallel loss of cardiolipin. Both these effects were directly and significantly correlated and also abolished by superoxide dismutase+catalase. These results demonstrate that ROS generation induces the dissociation of cytochrome c from IMM via cardiolipin peroxidation. The data may prove useful in clarifying the molecular mechanism underlying the release of cytochrome c from the mitochondria to the cytosol.


Assuntos
Apoptose , Cardiolipinas/metabolismo , Grupo dos Citocromos c/metabolismo , Peroxidação de Lipídeos , Mitocôndrias/metabolismo , Miocárdio/citologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Catalase/metabolismo , Bovinos , Transporte de Elétrons , Radicais Livres/metabolismo , Miocárdio/metabolismo , Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Tempo
18.
J Biol Chem ; 276(47): 43693-8, 2001 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-11557756

RESUMO

Human unhydroxylated homotrimeric triple-helical collagen I produced in transgenic plants was used as an experimental model to provide insights into the role of hydroxyproline in molecular folding and fibril formation. By using chemically cross-linked molecules, we show here that the absence of hydroxyproline residues does not prevent correct folding of the recombinant collagen although it markedly slows down the propagation rate compared with bovine fully hydroxylated homotrimeric collagen I. Relatively slow cis-trans-isomerization in the absence of hydroxyproline likely represents the rate-limiting factor in the propagation of the unhydroxylated collagen helix. Because of the lack of hydroxylation, recombinant collagen molecules showed increased flexibility as well as a reduced melting temperature compared with native homotrimers and heterotrimers, whereas the distribution of charged amino acids was unchanged. However, unlike with bovine collagen I, the recombinant collagen did not self-assemble into banded fibrils in physiological ionic strength buffer at 20 degrees C. Striated fibrils were only obtained with low ionic strength buffer. We propose that, under physiological ionic strength conditions, the hydroxyl groups in the native molecule retain water more efficiently thus favoring correct fibril formation. The importance of hydroxyproline in collagen self-assembly suggested by others from the crystal structures of collagen model peptides is thus confirmed experimentally on the entire collagen molecule.


Assuntos
Colágeno Tipo I/metabolismo , Hidroxiprolina/fisiologia , Plantas Geneticamente Modificadas/genética , Dobramento de Proteína , Animais , Bovinos , Colágeno Tipo I/biossíntese , Colágeno Tipo I/química , Colágeno Tipo I/genética , Eletroforese em Gel de Poliacrilamida , Conformação Proteica
19.
J Biol Chem ; 276(26): 24352-9, 2001 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-11423559

RESUMO

Although the collagen V heterotrimer is known to be involved in the control of fibril assembly, the role of the homotrimer in fibrillar organization has not yet been examined. Here, the production of substantial amounts of recombinant collagen V homotrimer has allowed a detailed study of its role in homotypic and heterotypic fibril formation. After removal of terminal regions by pepsin digestion, both the collagen V heterotrimer and homotrimer formed thin homotypic fibrils, thus showing that diameter limitation is at least in part an intrinsic property of the collagen V triple helix. When mixed with collagen I, however, various complementary approaches indicated that the collagen V heterotrimer and homotrimer exerted different effects in heterotypic fibril formation. Unlike the heterotrimer, which was buried in the fibril interior, the homotrimer was localized as thin filamentous structures at the surface of wide collagen I fibrils and did not regulate fibril assembly. Its localization at the fibril surface suggests that the homotrimer can act as a molecular linker between collagen fibrils or macromolecules in the extracellular matrix or both. Thus, depending on their respective distribution in tissues, the different collagen V isoforms might fulfill specific biological functions.


Assuntos
Colágeno/química , Colágeno/metabolismo , Animais , Bovinos , Colágeno/ultraestrutura , Imuno-Histoquímica , Cinética , Trombina/química
20.
J Biol Chem ; 276(29): 27051-7, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11358968

RESUMO

The processing of the fibrillar procollagen precursors to mature collagens is an essential requirement for fibril formation. The enzymes involved in these events are known as the procollagen N and C proteinases. The latter, which cleaves the C-propeptides of the fibrillar procollagens I-III, is identical to the previously described bone morphogenetic protein-1 (BMP-1). Surprisingly, unlike the other fibrillar collagens, the processing of the C-propeptide domain of the procollagen V homotrimer was found to be mediated by furin rather than BMP-1. However, the presence of putative BMP-1 cleavage sites in the alpha1(V) C-propeptide sequence prompted us to reconsider the procollagen V C-propeptide cleavage by BMP-1. Using a recombinant system to produce substantial amounts of the proalpha1(V) homotrimer, we have previously shown that the C-propeptide is spontaneously released in the culture medium. The trimeric C-propeptide fragment, resulting from the furin cleavage, still encompassed the predicted BMP-1 cleavage sites. It was purified and tested as a substrate for BMP-1. In parallel, the release of the C-propeptide in the culture medium was inhibited by the addition of a specific furin inhibitor, allowing the re-examination of BMP-1 activity on the intact molecule. We showed that BMP-1 does cleave both substrates at one of the two predicted C-proteinase cleavage sites. Our results favor a role for PCP/BMP-1 in physiological C-terminal processing of procollagen V and imply a general mechanism for fibrillar collagen C-terminal processing.


Assuntos
Proteínas Morfogenéticas Ósseas/fisiologia , Metaloendopeptidases/fisiologia , Pró-Colágeno/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Sequência de Aminoácidos , Proteína Morfogenética Óssea 1 , Linhagem Celular , Meios de Cultura , Humanos , Hidrólise , Pró-Colágeno/química , Proteínas Recombinantes/metabolismo
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