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1.
BJA Open ; 2: 100011, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37588269

RESUMO

Airway stents are primarily inserted for the management of airway obstruction associated with an inoperable malignancy and are rarely indicated in benign disease. We outline the complications associated with tracheal stents and describe the use of veno-venous extracorporeal membrane oxygenation (V-V ECMO) to facilitate open tracheal surgery in an apnoeic patient who had an uncovered metallic tracheal stent left in place for an inappropriately long period. Computerised tomography imaging of the neck and thorax provided information for operative planning and described of the stent in addition to the extensive granulation tissue at the distal end of the stent. Veno-venous extracorporeal membrane oxygenation was used to facilitate open tracheal surgery, removal of the tracheal stent and formation of a surgical tracheostomy. Prolonged use of an uncovered metallic airway stent in younger patients with benign disease may lead to the stent being difficult to remove. There may be an accumulation of granulation tissue with the risk of airway obstruction.

3.
Forensic Chem ; 192020.
Artigo em Inglês | MEDLINE | ID: mdl-33458452

RESUMO

This manuscript outlines a straight-forward procedure for generating a map of similarity between spectra of a set. When applied to a reference set of spectra for Type I fentanyl analogs (molecules differing from fentanyl by a single modification), the map illuminates clustering that is applicable to automated structure assignment of unidentified molecules. An open-source software implementation that generates mass spectral similarity mappings of unknowns against a library of Type I fentanyl analog spectra is available at http://github.com/asm3-nist/FentanylClassifier.

5.
J Ir Dent Assoc ; 62(1): 55-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27169268

RESUMO

STATEMENT OF THE PROBLEM: Concerns were expressed that postoperative written instructions following endodontic treatment are not available in the Dublin Dental University Hospital. MATERIALS AND METHODS: Data was collected in three phases: retrospective analysis of clinical notes for evidence of the delivery of postoperative instructions; a randomly distributed questionnaire to patients undergoing root canal treatment prior to the introduction of a written postoperative advice sheet; and, another survey following introduction of the advice sheet. RESULTS: Some 56% of patients' charts documented that postoperative advice was given. Analysis of phase two revealed that patients were not consistently informed of any key postoperative messages. In phase 3 analysis, the proposed benchmarks were met in four out of six categories. CONCLUSIONS: Postoperative advice after root canal treatment in the DDUH is both poorly recorded and inconsistently delivered. A combination of oral postoperative instructions and written postoperative advice provided the most effective delivery of patient information.


Assuntos
Auditoria Odontológica , Folhetos , Educação de Pacientes como Assunto/métodos , Cuidados Pós-Operatórios , Tratamento do Canal Radicular , Adolescente , Adulto , Idoso , Benchmarking , Comunicação , Estudos Controlados Antes e Depois , Registros Odontológicos , Restauração Dentária Permanente , Restauração Dentária Temporária , Edema/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/etiologia , Complicações Pós-Operatórias , Estudos Prospectivos , Estudos Retrospectivos , Redação , Adulto Jovem
6.
Eur J Dent Educ ; 20(1): 9-13, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25409761

RESUMO

AIM: To assess and evaluate the confidence of the undergraduate dental team in Irish dental schools regarding their training in the field of special care dentistry (SCD). METHOD: A questionnaire was distributed amongst the undergraduate dental teams within Cork University Dental School and Hospital (CUDSH) and Dublin Dental University Hospital (DDUH). The data were analysed to assess for differences between the median responses of the various groups. RESULTS: A total of 139 students participated in the study; 82 from DDUH (59 dental science students, seven dental hygiene students and 16 dental nursing students) and 57 from CUDSH (43 dental science students and 14 dental hygiene students). Twenty-two per cent (n = 30) of respondents agreed that their training had been sufficient in providing treatment or assistance for patients requiring SCD. Seventy-five per cent agreed that more emphasis should be placed on clinical training in SCD (n = 76). Thirty-one per cent of students anticipated a high level of confidence in treating patients requiring SCD upon graduation (n = 43), with dental science students feeling the least prepared amongst the dental team. CONCLUSION: Confidence levels of the undergraduate dental team were low with regard to SCD. The existing hands-on clinical training in SCD was deemed insufficient by the respondents. Students believed more emphasis should be placed on SCD training in the undergraduate curriculum.


Assuntos
Educação em Odontologia/métodos , Higiene Bucal/educação , Especialidades Odontológicas/educação , Adulto , Currículo , Feminino , Humanos , Irlanda , Masculino , Equipe de Assistência ao Paciente , Faculdades de Odontologia , Inquéritos e Questionários
7.
Curr Mol Med ; 14(5): 690-702, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24894172

RESUMO

Frequent outbreaks caused by influenza viruses pose considerable public health threats worldwide. Virus-inflicted alveolar damage represents a major contributor of acute lung injury in influenza. We have previously demonstrated that hepatocyte growth factor (HGF) produced by macrophages enhances alveolar epithelial proliferation during influenza infection. Here, we investigated the therapeutic efficacy of recombinant human HGF (rhHGF) and an antiviral agent (oseltamivir) alone or in combination to treat influenza viral pneumonia in macrophage-depleted BALB/c mice. Combination therapy of infected mice significantly reduced lung pathology and mortality compared to other animal groups that received either treatment alone. Combination treatment with rhHGF induced alveolar type II (AT2) epithelial hyperplasia more prominently in the distal airways, evident by increased cells with double-positive staining for surfactant protein-C and proliferating cell nuclear antigen within the alveolar epithelial lining. Similarly, rhHGF supplementation also induced stem cell antigen-1 (SCA-1) transcriptional expression at 5 days post-infection (dpi), but mRNA levels of both SCA-1 and its receptor c-KIT were decreased by 10 dpi. Microarray and pathway analyses indicated that rhHGF administration may act by accelerating tissue repair and suppressing inflammatory processes to minimize damage by infection and to restore lung function by earlier repair. These results reveal that transient administration of rhHGF may confer synergistic effects in enhancing pulmonary repair by promoting AT2 cell proliferation. Thus, the combination of rhHGF and oseltamivir may represent a promising therapeutic option against influenza pneumonia to improve existing antiviral treatment regimens.


Assuntos
Antivirais/uso terapêutico , Fator de Crescimento de Hepatócito/uso terapêutico , Influenza Humana/tratamento farmacológico , Oseltamivir/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Animais , Quimioterapia Combinada , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C
8.
J Dent Res ; 91(7 Suppl): 79S-84S, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22699673

RESUMO

This double-blind, randomized, clinical trial investigated the effectiveness and underlying mechanism of neural inhibition of pulsed Nd:YAG laser induction of pulpal analgesia compared with 5% EMLA anesthetic cream. Forty-four paired premolars from 44 orthodontic patients requiring bilateral premolar extraction from either dental arch were randomly assigned to the 'Laser plus Sham-EMLA' or 'EMLA plus Sham-Laser' treatment group. Analgesia was tested by an Electric Pulp Tester (EPT) and the cutting of a standardized cavity, which was terminated when participants reported sensitivity, and Visual Analogue Scale (VAS) and numbness were recorded. Statistical analyses were done by paired t test, McNemar's test, and a chi-squared test (p < 0.05). Sixty-eight percent of laser- and 59% of EMLA-treated teeth had completed cavities with statistically significant EPT increases above baseline. No significant within-patient differences were found for either group. No laser-treated participants reported numbness. The trial confirmed that the pulsed Nd:YAG laser effectively induced pulpal analgesia, by suppression of intradental nerve responses to electrical and mechanical stimuli. Such a laser provides an alternative for dental pain management (ANZ-Clinical Trial Registry: N12611001099910).


Assuntos
Anestesia Dentária/métodos , Anestesia Local/métodos , Polpa Dentária/efeitos da radiação , Lasers de Estado Sólido/uso terapêutico , Terapia com Luz de Baixa Intensidade/métodos , Adolescente , Anestésicos Combinados/administração & dosagem , Anestésicos Locais/administração & dosagem , Dente Pré-Molar/inervação , Dente Pré-Molar/efeitos da radiação , Preparo da Cavidade Dentária/instrumentação , Polpa Dentária/inervação , Teste da Polpa Dentária/instrumentação , Método Duplo-Cego , Feminino , Humanos , Lidocaína/administração & dosagem , Combinação Lidocaína e Prilocaína , Masculino , Inibição Neural , Medição da Dor , Limiar da Dor/fisiologia , Prilocaína/administração & dosagem , Transmissão Sináptica/efeitos da radiação , Extração Dentária
9.
J Dent ; 40(6): 500-5, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22390980

RESUMO

OBJECTIVES: To assess the cuspal deflection and cervical microleakage of standardised Class II cavities incrementally filled with a dimethacrylate RBC or bulk-fill flowable RBC bases. METHODS: Twenty-four sound upper premolar teeth with Class II cavities were allocated to three groups (n=8). Restoration of the teeth involved the placement of an RBC (GrandioSO) in eight oblique increments (Group A) or Groups B and C were restored to within 2 mm of the palatal cusp in a single increment with bulk-fill flowable RBC bases (SDR and x-tra base) before the two occlusal cavity increments were placed with GrandioSO. Buccal and palatal cusp deflections were recorded postirradiation using a twin channel deflection measuring gauge. Following restoration, the teeth were thermocycled, immersed in 0.2% basic fuchsin dye for 24h, sectioned and examined for cervical microleakage. RESULTS: The mean total cuspal deflection for the oblique incremental restoration technique was 11.26 (2.56) µm (Group A) and 4.63 (1.19) µm (Group B) and 4.73 (0.99) µm (Group C) for the bulk-fill flowable RBC bases. A significant increase in the mean total cuspal deflection for the incrementally filled GrandioSO compared with the SDR (P=0.007) and x-tra base (P=0.005) restored teeth was evident. No significant difference in the cervical microleakage scores was recorded between groups AC (P>0.05). CONCLUSIONS: The bulk-fill flowable RBC bases significantly reduced cuspal deflection compared with a conventional RBC restored in an oblique incremental filling technique with no associated change in cervical microleakage recorded.


Assuntos
Dente Pré-Molar/fisiologia , Resinas Compostas/química , Infiltração Dentária/classificação , Materiais Dentários/química , Restauração Dentária Permanente/métodos , Coroa do Dente/fisiologia , Corantes , Lâmpadas de Polimerização Dentária/classificação , Preparo da Cavidade Dentária/classificação , Restauração Dentária Permanente/classificação , Adesivos Dentinários/química , Humanos , Teste de Materiais , Metacrilatos/química , Corantes de Rosanilina , Estresse Mecânico , Temperatura , Fatores de Tempo
11.
Genes Immun ; 9(4): 316-27, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18401353

RESUMO

Interleukin-10 (IL-10) is intensely studied, yet little is known about the mechanisms that control IL-10 expression. We identified striking similarities between IL-10 and interferon-gamma (IFN-gamma) regulation in mouse natural killer (NK) cells. Like IFN-gamma, IL-10 expression is induced by IL-2 and IL-12 and IL-2+IL-12 stimulation is synergistic. Unlike IFN-gamma, neither IL-18 nor Ly-49D cross-linking induced IL-10 expression however. Additionally, the IL-12 homologs IL-23 and IL-27 also do not regulate NK cell-specific IL-10. We determined that a small population of NK cells accounts for IL-10 production. The induction of IL-10 by IL-2+IL-12 treatment in NK cells appears to be biphasic, with an initial burst of expression which diminishes by 12 h but spikes again at 18 h. We determined that much like IFN-gamma, Stat4 is largely required for IL-12-induced IL-10. Conversely, we observed normal induction of IL-10 in T-bet-deficient NK cells. We identified a Stat4-binding element in the fourth intron of the Il10 gene, which is completely conserved between mouse and human. This intronic Stat4 motif is within a conserved noncoding sequence, which is also a target for cytokine-induced histone acetylation. These findings highlight tissue- and receptor-specific IL-10 regulatory mechanisms, which may be part of an early feedback loop.


Assuntos
Interleucina-10/biossíntese , Células Matadoras Naturais/imunologia , Fator de Transcrição STAT4/metabolismo , Proteínas com Domínio T/fisiologia , Animais , Técnicas de Cultura de Células , Células Cultivadas , Sinergismo Farmacológico , Interferon gama/metabolismo , Interleucina-10/genética , Interleucina-12/farmacologia , Interleucina-2/farmacologia , Células Matadoras Naturais/metabolismo , Cinética , Camundongos , Camundongos Endogâmicos C57BL , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Fator de Transcrição STAT4/química , Fator de Transcrição STAT4/genética , Baço/citologia , Estimulação Química , Fatores de Tempo
12.
Cell Death Differ ; 13(11): 1968-81, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16543941

RESUMO

Aplidin is an antitumor agent in phase II clinical trials that induces apoptosis through the sustained activation of Jun N-terminal kinase (JNK). We report that Aplidin alters glutathione homeostasis increasing the ratio of oxidized to reduced forms (GSSG/GSH). Aplidin generates reactive oxygen species and disrupts the mitochondrial membrane potential. Exogenous GSH inhibits these effects and also JNK activation and cell death. We found two mechanisms by which Aplidin activates JNK: rapid activation of Rac1 small GTPase and downregulation of MKP-1 phosphatase. Rac1 activation was diminished by GSH and enhanced by L-buthionine (SR)-sulfoximine, which inhibits GSH synthesis. Downregulation of Rac1 by transfection of small interfering RNA (siRNA) duplexes or the use of a specific Rac1 inhibitor decreased Aplidin-induced JNK activation and cytotoxicity. Our results show that Aplidin induces apoptosis by increasing the GSSG/GSH ratio, a necessary step for induction of oxidative stress and sustained JNK activation through Rac1 activation and MKP-1 downregulation.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Proteínas de Ciclo Celular/genética , Depsipeptídeos/farmacologia , Dissulfeto de Glutationa/metabolismo , Proteínas Imediatamente Precoces/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fosfoproteínas Fosfatases/genética , Proteínas Tirosina Fosfatases/genética , Proteínas rac1 de Ligação ao GTP/metabolismo , Animais , Antineoplásicos/farmacologia , Neoplasias da Mama/enzimologia , Neoplasias da Mama/metabolismo , Cálcio/metabolismo , Cobre/metabolismo , Regulação para Baixo/efeitos dos fármacos , Fosfatase 1 de Especificidade Dupla , Ativação Enzimática/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Células HeLa , Homeostase/efeitos dos fármacos , Humanos , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Membranas Mitocondriais/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Peptídeos Cíclicos , Proteína Fosfatase 1 , Espécies Reativas de Oxigênio/metabolismo
13.
J Indian Med Assoc ; 104(12): 689-91, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17474287

RESUMO

The incidence and prevalence of non-communicable diseases such as diabetes mellitus, hypertension, cardiovascular disease and cancer are on the rise. The awareness about chronic kidney disease and its burden on the society is highlighted in the last decade in developed countries. However, this is not the case in India, where studies have shown the prevalence of terminal kidney disease is 785 people per million population. Chronic kidney disease is insidious in onset, slowly progressive, often asymptomatic, irreversible and resulting from fibrosis and scaring in the kidneys. Intervention at an early stage has shown to slow the progression and hence reduces cardiovascular morbidity and mortality. Hence, early detection programmes in susceptible individuals including those with diabetes mellitus, hypertension and family history of kidney disease will have major impact on the health of the population.


Assuntos
Surtos de Doenças/prevenção & controle , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/prevenção & controle , Programas de Rastreamento , Progressão da Doença , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Incidência , Índia/epidemiologia , Falência Renal Crônica/diagnóstico , Prevalência , Fatores de Tempo
14.
Rev Sci Tech ; 24(3): 909-20, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16642761

RESUMO

Analysis of retrospective quantitative sheep pox epidemiological data from the Government Animal Husbandry Department, Karnataka, India, covering 24 years revealed significant information on sheep pox. The state has a dense sheep population including some valuable breeds. Data revealed the endemicity of the disease: there were a considerable number of outbreaks and attacks, high mortality and case fatality rates and low immunisation coverage. None of the years studied were free from infection. Temporally, the disease was most prevalent between November and May. Spatially, the disease was recorded in 19 out of 27 districts; in some of these districts sheep pox was highly endemic, in some it was endemic at low levels and in the remaining districts outbreaks occurred sporadically. Environmental factors influenced disease occurrence. Vaccine production met only one tenth of the requirement, and its peak utilisation was in the dry season.


Assuntos
Capripoxvirus , Infecções por Poxviridae/veterinária , Doenças dos Ovinos/epidemiologia , Vacinas Virais/administração & dosagem , Animais , Cruzamento , Clima , Surtos de Doenças/veterinária , Feminino , Índia/epidemiologia , Masculino , Infecções por Poxviridae/epidemiologia , Infecções por Poxviridae/mortalidade , Estudos Retrospectivos , Estações do Ano , Ovinos
15.
Trop Anim Health Prod ; 36(4): 307-20, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15241965

RESUMO

A classical live attenuated sheep pox vaccine was prepared using the Ranipet strain of sheep pox virus (SPV) at the 50th passage in a secondary lamb testicular cell system. The TCID50 and RD50 were 10(9.63)/ml and 10(9.51)/ml. respectively. The SID50 of SPV challenge virus was 10(5)/ml. The vaccine was found to have no adverse effects in laboratory animals, and was safe and effective in SPV seronegative lambs. In the field, 660 sheep were vaccinated with an immunizing dose containing 1 x 10(2) TCID50. Randomly selected vaccinated sheep mounted good cell-mediated immunity and humoral responses as measured by glucose utilization test and serum neutralization test, respectively, for the study period of 6 months.


Assuntos
Capripoxvirus/imunologia , Infecções por Poxviridae/prevenção & controle , Infecções por Poxviridae/veterinária , Doenças dos Ovinos/prevenção & controle , Doenças dos Ovinos/virologia , Vacinas Virais/imunologia , Vacinas Virais/uso terapêutico , Animais , Temperatura Corporal , Feminino , Glucose/metabolismo , Cobaias , Imunização/métodos , Imunização/veterinária , Masculino , Camundongos , Testes de Neutralização/veterinária , Infecções por Poxviridae/imunologia , Infecções por Poxviridae/virologia , Ovinos , Doenças dos Ovinos/imunologia , Vacinas Atenuadas/efeitos adversos , Vacinas Atenuadas/imunologia , Vacinas Atenuadas/uso terapêutico , Vacinas Virais/efeitos adversos
16.
Aust Dent J ; 47(1): 68-71, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12035962

RESUMO

Displacement of root fragments into adjacent anatomical areas is an uncommon complication of the removal of teeth. This paper describes the management of a mandibular third molar root fragment that was forced into the antero-inferior aspect of the pterygomandibular space. The importance of tomographical radiographs in the visualization of the displaced root is also discussed.


Assuntos
Corpos Estranhos , Músculos Pterigoides , Raiz Dentária , Adulto , Feminino , Corpos Estranhos/etiologia , Corpos Estranhos/cirurgia , Humanos , Mandíbula/diagnóstico por imagem , Dente Serotino/cirurgia , Tomografia Computadorizada por Raios X , Extração Dentária/efeitos adversos
17.
Eur J Immunol ; 31(9): 2690-701, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11536167

RESUMO

Glycosylation of mammalian proteins is known to influence their intracellular trafficking, half life, and susceptibility to enzymatic degradation. Rare instances of natural T cell epitopes dependent upon glycosylation for recognition have been described. We report here on human CD4(+) T lymphocyte cultures and clones from two melanoma patients that recognize the melanoma-associated Ag tyrosinase in the context of HLA-DR4 and -DR8. These T cells recognize tyrosinase, normally a heavily glycosylated molecule, when expressed constitutively in melanoma cells or in COS-7 transfectants pulsed as lysates onto autologous APC. However, these T cells fail to recognize tyrosinase expressed in bacteria, nor do they react with overlapping peptides covering full-length tyrosinase, suggesting a critical role for glycosylation in the processing and / or composition of the stimulatory epitopes. The requirement for glycosylation was demonstrated by the failure of tyrosinase-specific CD4(+) T cells to recognize tyrosinase synthesized in the presence of glycosylation inhibitors, or deglycosylated enzymatically. Site-directed mutagenesis of each of seven potential N-glycosylation sites showed that four sites were required to generate forms of tyrosinase that could be recognized by individual T cell clones. These data indicate that certain carbohydrate moieties are required for processing the tyrosinase peptides recognized by CD4(+) T cells. Post-translational modifications of human tumor-associated proteins such as tyrosinase could be a critical factor for the development of antitumor immune responses.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Carboidratos/fisiologia , Antígenos de Histocompatibilidade Classe II/imunologia , Melanoma/imunologia , Monofenol Mono-Oxigenase/química , Monofenol Mono-Oxigenase/imunologia , Animais , Antígenos de Neoplasias/química , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Células COS , Linhagem Celular , Células Clonais , Epitopos de Linfócito T/química , Epitopos de Linfócito T/imunologia , Glicoproteínas/biossíntese , Glicosilação , Humanos , Monofenol Mono-Oxigenase/genética , Mutagênese Sítio-Dirigida , Células Tumorais Cultivadas
18.
J Biomol Struct Dyn ; 19(1): 47-57, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11565851

RESUMO

Calcium plays a key role in cellular signal transduction. Calmodulin, a protein binding four calcium ions, is found in all eukaryotic cells and is believed to activate such processes. The calcium binding loop found in this protein, the canonical EF-hand, is also found in a large number of other proteins such as troponins, parvalbumins, calbindins etc. Earlier analysis of the amino acid sequences of these proteins with a view of understanding evolution of protein families and signaling mechanisms have provided extensive evidence for a characteristic double gene duplication event in this family of proteins. These analyses have been extended here to the three dimensional structures and the biophysical properties of the sequence segments of calmodulin EF-hands. The clear evolutionary history that shows up in sequences is not reflected as clearly in the conformation of individual EF-hands, which may be a consequence of the much higher conservation pressure on the structure. Some evidence for the proposed gene duplication is implicit in the apo-holo structural transitions of the EF-hands. The profile of amino acid properties that might be significant for calcium binding, however, clearly reflects the gene duplication. These profiles might also provide insightful information on the calcium affinity of the EF-hand motifs and the nature of amino acid residues that constitute them.


Assuntos
Calmodulina/química , Sequência de Aminoácidos , Animais , Sítios de Ligação , Cálcio/metabolismo , Calmodulina/genética , Calmodulina/metabolismo , Simulação por Computador , Sequência Conservada , Evolução Molecular , Duplicação Gênica , Modelos Moleculares , Paramecium tetraurellia , Conformação Proteica , Estrutura Secundária de Proteína , Xenopus laevis
19.
J Am Soc Mass Spectrom ; 12(12): 1296-301, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11766756

RESUMO

The modulation of calcium binding by the EF-hand motifs present in a calmodulin (CAM) homologue, a calcium binding protein (CaBP) from Entamoeba histolytica by three external parameters-pH, ligand coordinator EGTA, and fragmentor voltage was investigated by mass spectrometry. Calcium binding follows expected patterns at highly acidic and alkaline pH with the preponderance of the apo and the completely saturated forms, respectively. Surprisingly, additional nonspecific binding is observed near neutral pH. Studies on EGTA chelation and effects of fragmentor voltage showed cooperativity in calcium removal in at least one of the domains. Similar studies on a smaller construct containing the two high affinity carboxy terminal sites revealed interesting differences and provided an estimate of the specificity and tolerance of the EF-hand motifs to calcium binding and removal.


Assuntos
Proteínas de Ligação ao Cálcio/química , Cálcio/química , Calmodulina/química , Proteínas de Ligação ao Cálcio/biossíntese , Calmodulina/biossíntese , Clonagem Molecular , Ácido Egtázico , Concentração de Íons de Hidrogênio , Metais/química , Estrutura Quaternária de Proteína , Espectrometria de Massas por Ionização por Electrospray
20.
FEBS Lett ; 461(1-2): 19-24, 1999 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-10561489

RESUMO

The thermodynamics of interaction of two model peptides melittin and mastoparan with bovine brain calmodulin (CAM) and a smaller CAM analogue, a calcium binding protein from Entamoeba histolytica (CaBP) in 10 mM MOPS buffer (pH 7.0) was examined using isothermal titration calorimetry (ITC). These data show that CAM binds to both the peptides and the enthalpy of binding is endothermic for melittin and exothermic for mastoparan at 25 degrees C. CaBP binds to the longer peptide melittin, but does not bind to mastoparan, the binding enthalpy being endothermic in nature. Concurrently, we also observe a larger increase in alpha-helicity upon the binding of melittin to CAM when compared to CaBP. The role of hydrophobic interactions in the binding process has also been examined using 8-anilino-1-naphthalene-sulphonic acid (ANS) binding monitored by ITC. These results have been employed to rationalize the energetic consequences of the binding reaction.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Calmodulina/análogos & derivados , Calmodulina/metabolismo , Peptídeos/metabolismo , Sequência de Aminoácidos , Naftalenossulfonato de Anilina/metabolismo , Animais , Calorimetria , Dicroísmo Circular , Entamoeba histolytica/metabolismo , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Peptídeos e Proteínas de Sinalização Intercelular , Meliteno/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Ligação Proteica , Estrutura Secundária de Proteína , Proteínas Recombinantes , Homologia de Sequência de Aminoácidos , Termodinâmica , Venenos de Vespas/metabolismo
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