RESUMO
Freehand 3D ultrasound (3D-US) is a promising technique for measuring muscle volume but it requires gel pads or water tanks to limit probe compression on the skin which makes it hard to use in clinical applications. Our objectives were to measure the effect of different compressions on muscle volume in order to assess the clinical applicability of a minimal compression method for lower limb muscles. 4 muscles of the lower limb on 15 healthy volunteers were scanned with a new commercial freehand 3D-US setup accessible to clinical experimentators. Each muscle was scanned with 3 levels of compression: standard compression, minimal compression and gel pad (method validated against MRI). Volume was calculated using software segmentation tools. Acquisitions and segmentations were done by the same examiner. There was a significant impact of standard compression on volume measurements, but no difference between minimal compression and gel pad. Standard compression underestimated volume with a mean bias of 16 mL. For minimal compression, 75 % of measured differences were below the predefined clinically acceptable limits of 10 mL. Mean bias for this method was 1.1 mL. In conclusion, standard compression in freehand 3D-US induces a systematic bias in volume calculations. But, with a trained examiner and the necessary precautions to minimize compression, this bias could be abolished and become acceptable in clinical applications. When a high accuracy is required, gel pads could still be important to consider.
Assuntos
Imageamento Tridimensional , Músculo Esquelético , Humanos , Imageamento Tridimensional/métodos , Ultrassonografia/métodos , Músculo Esquelético/diagnóstico por imagem , Software , Imageamento por Ressonância Magnética/métodosRESUMO
INTRODUCTION: Termination of pregnancy for maternal reasons (MTOP) are authorized in France without limit of term when "the continuation of the pregnancy puts in serious danger the health of the woman". The literature on the subject is rare and we wanted to make an inventory in our region. METHODS: Retrospective observational study between 2010 and 2019 at the multidisciplinary center for prenatal diagnosis in Western Normandy. RESULTS: Thirty-one cases of MTOP were included (2.5% of all TOP). At the CHU de Caen, they represented one in 1200 births. Twenty-three percent of MTOP had a psychosocial or psychiatric indication (average term=22 SA) and 29% an obstetric indication due to severe preeclampsia (23 SA). Finally, 48% were linked to a non-obstetric somatic disorder including 46% pre-existing pathologies (average term=11 SA), most often cardiological or nephrological and 54% diagnosed during pregnancy (17 SA) dominated by neoplasias. They were more often (68%) performed in the second trimester. Vaginal births were more frequent (74% against 26% of endouterine aspirations). CONCLUSION: Strict medical contraindications to pregnancy are exceptional. Recourse to the medical termination of pregnancy within the framework of a preexisting pathology must remain rare, by systematizing of the preconception consultation.
Assuntos
Aborto Induzido , Pré-Eclâmpsia , Feminino , Humanos , Gravidez , Segundo Trimestre da Gravidez , Diagnóstico Pré-Natal , Estudos RetrospectivosRESUMO
OBJECTIVE: Compare obstetrician intervention and calling rates during labour and delivery between low-risk and high-risk women and study the influence of parity on these rates. MATERIAL AND METHODS: Descriptive retrospective study conducted on 227 patients in a university maternity unit (level 3 university hospital maternity unit) between 1st and 30th January 2014. The low- and high-risk populations were characterised according to the French National Authority for Health (HAS) and NICE guidelines. The obstetrician intervention criteria were: Caesarean section, instrumental vaginal delivery, artificial delivery/uterus examination and postpartum haemorrhage. The obstetrical team also had to call the obstetrician in case of foetal heart rate abnormalities, scalp blood pH measurement, third and/or fourth degree perineal tears, labour dystocia, or any other severe event occurring during labour or delivery. RESULTS: In univariate analysis, the obstetrician intervention rates were respectively 44.5% and 34.4% in the high- and low-risk groups (P=0.13). The obstetrician calling rates were similar between the two groups. Using logistic regression model including parity, the obstetrician intervention rate became significantly higher in the "high-risk" group (OR 2.044, 95% CI 1.129-3.703, P=0.018). In the low-risk population, the intervention rate was significantly increased for nulliparous women compared with multiparas (47.5% versus 9.7%, P<0.001, OR=8.2, CI 95% 2.2 to 46.9). CONCLUSION: One third of the women defined as low-risk patients appear to need an obstetrician intervention during labour and delivery, with a major influence of parity.
Assuntos
Cesárea/estatística & dados numéricos , Parto Obstétrico/estatística & dados numéricos , Complicações do Trabalho de Parto/epidemiologia , Complicações do Trabalho de Parto/terapia , Paridade/fisiologia , Padrões de Prática Médica/estatística & dados numéricos , Adulto , Parto Obstétrico/métodos , Distocia/epidemiologia , Distocia/terapia , Feminino , França/epidemiologia , Humanos , Recém-Nascido , Obstetrícia/métodos , Obstetrícia/estatística & dados numéricos , Gravidez , Estudos Retrospectivos , Fatores de Risco , Adulto JovemRESUMO
Hospitals have to deal strong with economic constraints and increasing requirements in terms of quality and safety of care. To address these constraints, one solution could be the adoption of approaches from the industry sector. Following the decree of April 6, 2011 on the quality management of the medication use process, some of these approaches, such as risk management, are now part of the everyday work of healthcare professionals. However, other approaches, such as business process improvement, are still poorly developed in the hospital setting. In this general review, we discuss the main approaches of business process improvements that have been used in hospitals by focusing specifically on one of the newest and most currently used: Lean.
Assuntos
Administração Hospitalar/métodos , Gestão da Qualidade Total , Administração Hospitalar/normas , Hospitais , Humanos , Sistemas de Medicação no Hospital/normas , Segurança do PacienteRESUMO
Anorexia nervosa (AN) is a chronic and often severe eating disorder, which could have a serious impact on various life domains. AN may lead to physical, mental, behavioural and socioprofessional impairment. Thus, one could expect a poor quality of life (QoL) in AN patients. QoL is certainly a key factor to provide quantitative measurement of treatment efficacy that will facilitate clinical decision-making and treatment planning. Despite that QoL was rarely prospectively analyzed in AN patients, one could conclude that AN patients showed reduced QoL, as compared to normal controls and other psychiatric-disordered patients. It seems that mental health components of QoL are more impaired than the physical ones in AN patients, who showed a modest impact in the physical domain. Thus, our aim was to analyse the QoL using a new, French, questionnaire, the QUAVIAM (qualité de vie dans l'anorexie mentale). After a bibliography research (including EDE, EDI, SF-36, QOL.ED), the choice of 12 themes, regrouped in six scores, was made by three eating disorder specialists and two recovered patients. For each score, 10 to 15 questions were written by the experts, and then corrections and validation were made by the five experts and 21 patients. After this, we prospectively determined the reproducibility (3 days interval), the specificity, and the sensitivity for short-term change in patients exhibiting an "active" AN (n=54, mean age: 31 ± 9 yrs, mean BMI: 14.1 ± 2.8 kg/m(2), AN duration: 2.6 ± 1.9 yrs), and again after cognitive behavioral therapy (CBT). We also analyzed the QUAVIAM score and subscores in 48 recovering patients and in 56 subjects without eating disorder. The QUAVIAM final version (61 questions) was collected in 76 patients and the 56 healthy controls matched for sex and age. Its reproducibility was 91% (intra-questionnaire) and 94% (inter-questionnaire), its specificity 98% (versus controls; P<0.0001) and its sensitivity 99%. The QUAVIAM global score of the AN patients was more impaired (389 ± 87) than that of the recovering patients (157 ± 82) and the normal controls (89 ± 49; P<0.0001). Each of the six subscores was higher (more altered) in active AN than in recovering AN patients and in normal subjects: the somatic, the psychological, the hedonic, the socioprofessional, the affective and the TCA-related ones (P<0.001 for each comparison). The QUAVIAM global score and its subscores were significantly improved (decreased) by the 3-month CBT: 385 ± 25 before and 189 ± 30 after CBT (P<0.0001). The changes were observed for all the subscales (P<0.0001). The somatic subscore did not decrease less than the other subscores. Thus, the present study permits proposing the QUAVIAM for analysis of physical, mental, behavioural and socioprofessional impairment or improvements in AN patients.
Assuntos
Anorexia Nervosa/psicologia , Anorexia Nervosa/terapia , Terapia Cognitivo-Comportamental , Qualidade de Vida/psicologia , Inquéritos e Questionários , Adulto , Feminino , Seguimentos , França , Humanos , Masculino , Psicometria/estatística & dados numéricos , Valores de Referência , Reprodutibilidade dos Testes , Resultado do Tratamento , Adulto JovemRESUMO
This study aimed to experimentally acquire evolution profiles between depth, bulk density, Free Air Space (FAS), air permeability and thermal conductivity in initial composting materials. The impact of two different moisture content, two particle size and two types of bulking agent on these four parameters was also evaluated. Bulk density and thermal conductivity both increased with depth while FAS and air permeability both decreased with it. Moreover, depth and moisture content had a significant impact on almost all the four physical parameters contrary to particle size and the type of bulking agent.
Assuntos
Esgotos/análise , Esgotos/química , Solo/análise , Solo/química , Água/química , Módulo de Elasticidade , Dureza , Permeabilidade , Estresse Mecânico , Condutividade Térmica , Água/análiseRESUMO
This study analyzed the effect of population aging on organ donation for transplants in 43 countries and on the effectiveness of the donation process by comparing the results between Spain and the United States. The percentage of the population aged 65 or over accounted for 33% of the difference in the donation rates between the countries and for 91% of the variation in the rates after age adjustment. However, the level of aging of the Spanish (16.5%) and American (12.3%) populations failed to account for the percentages of deceased donors 65 or over (28% vs. 10%), due to the different age-specific donation rates, much higher in Spain above 50 years. These differences lead to a higher effectiveness of the process in the United States (3.1 transplanted organs per donor vs. 2.5 in Spain), though at lower rates of transplant per million population (73 vs. 87). We conclude that older populations have a greater donation potential as donation rates are strongly associated with population aging. It should therefore be mandatory to adjust donation rates for age before making comparisons. Additionally, effectiveness decreases with older donors, so age should be considered when establishing standards relating to organ donation and effectiveness of the process.
Assuntos
Envelhecimento/fisiologia , Doadores Vivos/estatística & dados numéricos , Transplante de Órgãos/estatística & dados numéricos , Dinâmica Populacional , Doadores de Tecidos/estatística & dados numéricos , Obtenção de Tecidos e Órgãos/métodos , Adolescente , Adulto , Distribuição por Idade , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Cadáver , Criança , Humanos , Pessoa de Meia-Idade , Transplante de Órgãos/mortalidadeRESUMO
Two chitinases, able to use tetra-N-acetylglucosamine, chitin and chitosan as substrates, were characterized after purification from Carica papaya latex. The complete amino acid sequence of the major form and about 40% of the minor one were determined through proteolytic digestions and mass spectroscopy analysis. Sequencing demonstrated that both papaya chitinases are members of the family 19 of glycosyl hydrolases (GH19). Based on the known 3-D structures of other members of family GH19, it was expected that papaya chitinases would adopt all-alpha structures. However, circular dichroism and infrared spectroscopy indicated, for the papaya chitinases, a content of 15-20% of extended structures besides the expected 40% of alpha helices. Since the fully sequenced papaya chitinase contains a large number of proline residues the possibility that papaya chitinase contains polyproline II stretches was examined in the context of their resistance against proteolytic degradation.
Assuntos
Carica/química , Quitinases/química , Sequência de Aminoácidos , Quitinases/genética , Quitinases/isolamento & purificação , Dicroísmo Circular , Endopeptidases/química , Fluorescência , Hidrolases/química , Modelos Moleculares , Dados de Sequência Molecular , Peptídeo Hidrolases/química , Análise de Sequência de Proteína , Homologia de Sequência de Aminoácidos , Espectrofotometria InfravermelhoRESUMO
A standard sample holder and vial for cryocooled macromolecular crystals has been defined for use with robotic sample changers. This SPINE standard sample holder is a modified version, with added features and specifications, of sample holders in common use. In particular, the SPINE standard meets the precision required for automatic sample exchange and includes a cap that is identified by a two-dimensional datamatrix code as well as an optional vial. At the ESRF, the sample holder standard is in use with the EMBL/ESRF/BM14 robotic sample changer (SC3) which is installed on eight beamlines. The SC3 can hold up to 50 crystals stored in five baskets. A datamatrix reader in the SC3 ensures safe management of the sample flow and facilitates fully automatic screening and characterization of samples. Tools for handling and transporting 50 samples in a dry shipping dewar have been developed. In addition to the SC3, the SPINE sample holder is currently compatible with a number of other robotic sample changers.
Assuntos
Cristalografia/instrumentação , Automação , Cristalografia/normas , Eletrônica , Magnetismo , Padrões de Referência , Robótica , Software , SíncrotronsRESUMO
Bacterial adherence is a complex phenomenon involving specific interactions between receptors, including matricial fibronectin, and bacterial ligands. We show here that fibronectin and outer membrane proteins of Pseudomonas fluorescens were able to inhibit adherence of P. fluorescens to fibronectin-coated wells. We identified at least six fibronectin-binding proteins with molecular masses of 70, 55, 44, 37, 32 and 28 kDa. The presence of native (32 kDa) and heat-modified forms (37 kDa) of OprF was revealed by immuno-analysis and the 44-kDa band was composed of three proteins, their N-terminal sequences showing homologies with Pseudomonas aeruginosa porins (OprD, OprE1 and OprE3).
Assuntos
Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias , Fibronectinas/metabolismo , Porinas/metabolismo , Pseudomonas fluorescens/metabolismo , Aderência Bacteriana , Western Blotting , Porinas/genética , Homologia de Sequência de AminoácidosRESUMO
1-Benzoyl-2-alkyl piperazines are strong inhibitors of Group I and II secreted PLA(2)s. An improvement of their activity was obtained by replacing the amide function by a sulfamide and by introduction of electrodonor substituents on the para position of the benzenesulfonyl moiety. Neither the position on one of the carbon of the piperazine ring nor the absolute configuration of this carbon have an effect on the affinity for one or the other group of PLA(2), but the lipophilicity remains for these series an essential parameter. In addition structure-activity relationships allow new hypothesis on interaction of these piperazine derivatives with the catalytic site of PLA(2)s.
Assuntos
Inibidores Enzimáticos/síntese química , Fosfolipases A/antagonistas & inibidores , Fator de Ativação de Plaquetas/antagonistas & inibidores , Sulfonamidas/síntese química , Sulfonamidas/farmacologia , Animais , Plaquetas/efeitos dos fármacos , Plaquetas/enzimologia , Cálcio/química , Domínio Catalítico/efeitos dos fármacos , Bovinos , Quelantes/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Concentração Inibidora 50 , Conformação Molecular , Pâncreas/efeitos dos fármacos , Pâncreas/enzimologia , Piperazinas/síntese química , Piperazinas/química , Piperazinas/farmacologia , Coelhos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Odorant-binding proteins (OBPs) are soluble, low-molecular-weight proteins secreted in the sensillum lymph surrounding the dendrites of olfactory sensilla from a wide range of insect species. These proteins play a role in the solubilization, transport and/or deactivation of pheromones and odorants. In order to study the relationships between the molecular structure in solution and their ligand-binding properties, we have (13)C/(15)N-double-labeled two divergent honeybee OBPs, called ASP1 and ASP2, in sufficient quantities to permit a full determination of the structure and dynamics using heteronuclear NMR spectroscopy. The recombinant labeled proteins produced by the methylotrophic yeast Pichia pastoris have been secreted into a buffered minimal medium using native insect signal peptide. Mass spectrometry and Edman sequencing showed a native-like processing with a labeling efficiency of secreted proteins greater than 98%. After dialysis, the recombinant proteins were purified to homogeneity by one-step reversed-phase liquid chromatography. The final yield after 4-day shake-flask liquid culture was approximately 60 and 100 mg/L for ASP1 and ASP2, respectively. The inexpensive overproduction of labeled recombinant ASP1 and ASP2 should allow NMR studies of the structures and ligand-binding analysis in order to understand the relationships between structure and biological function of these proteins.
Assuntos
Abelhas/química , Proteínas de Insetos , Ressonância Magnética Nuclear Biomolecular , Pichia/metabolismo , Receptores Odorantes/biossíntese , Animais , Isótopos de Carbono/metabolismo , Proteínas de Transporte/biossíntese , Proteínas de Transporte/química , Proteínas de Transporte/isolamento & purificação , Cromatografia , Clonagem Molecular/métodos , Isótopos de Nitrogênio/metabolismo , Receptores Odorantes/química , Receptores Odorantes/isolamento & purificação , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
In insects, the transport of airborne, hydrophobic odorants and pheromones through the sensillum lymph is generally thought to be accomplished by odorant-binding proteins (OBPs). We report the structural and functional properties of a honeybee OBP called ASP2, heterologously expressed by the yeast Pichia pastoris. ASP2 disulfide bonds were assigned after classic trypsinolysis followed by ion-spray mass spectrometry combined with microsequencing. The pairing [Cys(I)-Cys(III), Cys(II)-Cys(V), Cys(IV)-Cys(VI)] was found to be identical to that of Bombyx mori OBP, suggesting that this pattern occurs commonly throughout the highly divergent insect OBPs. CD measurements revealed that ASP2 is mainly constituted of alpha helices, like other insect OBPs, but different from lipocalin-like vertebrate OBPs. Gel filtration analysis showed that ASP2 is homodimeric at neutral pH, but monomerizes upon acidification or addition of a chaotropic agent. A general volatile-odorant binding assay allowed us to examine the uptake of some odorants and pheromones by ASP2. Recombinant ASP2 bound all tested molecules, except beta-ionone, which could not interact with it at all. The affinity constants of ASP2 for these ligands, determined at neutral pH by isothermal titration calorimetry, are in the micromolar range, as observed for vertebrate OBP. These results suggest that odorants occupy three binding sites per dimer, probably one in the core of each monomer and another whose location and biological role are questionable. At acidic pH, no binding was observed, in correlation with monomerization and a local conformational change supported by CD experiments.
Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteínas de Insetos , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Sequência de Aminoácidos , Animais , Abelhas , Sítios de Ligação , Bombyx , Calorimetria , Cromatografia , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Dimerização , Dissulfetos , Concentração de Íons de Hidrogênio , Ligantes , Espectrometria de Massas , Modelos Químicos , Dados de Sequência Molecular , Feromônios/metabolismo , Pichia/metabolismo , Ligação Proteica , Conformação Proteica , Estrutura Secundária de Proteína , Análise de Sequência de Proteína , Fatores de Tempo , Tripsina/metabolismo , Raios UltravioletaRESUMO
Fibromyxoma of the middle ear (a case report). We report an extremely rare case of fibromyxoma of the middle ear which was first suspected to be a cholesteatoma. Surgery was performed through a postauricular incision and pathologic study of the tumor gave us the final diagnosis. Fibromyxoma is an uncommon benign tumour of the head and neck region which usually arises in the jaw (1). Its local aggressivity and gelatinous consistency explain the difficulties to remove it radically and its frequent recurrences after treatment (2). Surgical resection with a wide excision seems to be the treatment of choice. Some authors advocate the use of Argon or CO2 laser to achieve the treatment. A review of the poor literature about this subject is discussed in this article.
Assuntos
Neoplasias da Orelha , Orelha Média , Fibroma , Colesteatoma da Orelha Média/diagnóstico , Neoplasias da Orelha/patologia , Neoplasias da Orelha/cirurgia , Feminino , Fibroma/patologia , Fibroma/cirurgia , Humanos , Pessoa de Meia-IdadeRESUMO
In insects, the transport of airborne, hydrophobic odorants and pheromones through the sensillum lymph is accomplished by olfactory-binding proteins (CBPs). We report the structural characterization of a honeybee OBP called ASP1 found in workers and drones, previously observed to bind queen pheromone components. A novel method based on ion-spray mass spectrometry analysis of cyanylation-induced cleavage products of partially reduced protein with Tris(2-carboxyethyl)phosphine was needed to determine the recombinant ASP1 disulfide bond pairing. It was observed to be Cys(I)-Cys(III), Cys(II)-Cys(V), Cys(IV)-Cys(VI), similar to those already described for other OBPs from honeybee and Bombyx mori suggesting that this pattern occurs commonly throughout the diverse family of insect OBPs. Circular dichroism revealed that ASP1 is an all-alpha protein in accordance with NMR preliminary data, but unlike lipocalin-like vertebrate OBPs.
Assuntos
Proteínas de Transporte/química , Dissulfetos/química , Proteínas de Insetos/química , Animais , Abelhas , Dicroísmo Circular , Estrutura Secundária de ProteínaRESUMO
Aphrodisin is a soluble glycoprotein of hamster vaginal discharges, which stimulates male copulatory behavior. Natural aphrodisin was purified and its post-translational modifications characterized by MALDI-MS peptide mapping. To evaluate its ability to bind small volatile ligands, the aphrodisiac protein was expressed in the yeast Pichia pastoris as two major isoforms differing in their glycosylation degree, but close in conformation to the natural protein. Dimeric recombinant aphrodisins were equally able to efficiently bind odors (2-isobutyl-3-methoxypyrazine and methyl thiobutyrate) and a pheromone (dimethyl disulfide), suggesting that they could act as pheromone carriers instead of, or in addition to, direct vomeronasal neuron receptor activators.
Assuntos
Feromônios/metabolismo , Proteínas/metabolismo , Atrativos Sexuais/metabolismo , Animais , Cricetinae , Feminino , Masculino , Espectrometria de Massas , Mesocricetus , Odorantes , Feromônios/química , Feromônios/genética , Pichia/genética , Ligação Proteica , Proteínas/química , Proteínas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Atrativos Sexuais/química , Atrativos Sexuais/genética , Vagina/metabolismoRESUMO
Excessive levels of PAF and cells of macrophage lineage appear to play an important role in neuronal cell injury, inflammatory syndrome, and HIV replication in CNS resulting in AIDS dementia complex (ADC). The beneficial effects of PAF receptor antagonists are evident and give rise to expected therapeutic strategies for neurotrauma. Piperazine derivatives bearing a "cache-oreilles" (ear-muff) electronic distribution are able to inhibit in vitro PAF effects and, thus, could be used in pathologies where this mediator is involved. Therefore, their potential anti-HIV activity was investigated, and we find that (i) these PAF antagonists are effectively active in HIV-infected monocyte-derived macrophages (MDM) but there is no correlation between both anti-HIV and anti-PAF activities; (ii) the presence of a carbamate function (compounds 1a-d) is favorable to the antiviral activity; (iii) the lipophilicity of the substituent on the piperazinic cycle seems to be less important for the anti-PAF activity than for the antiviral one. Our leading compound, PMS 601 (compound 1a), presents a dual activity with IC(50) of 8 and 11 microM for anti-PAF and anti-HIV activity, respectively, without cytotoxic events at 1000 microM in MDM. Although its mode of action is not clearly defined, these data suggest that PMS 601, which displays no effect on acellular reverse transcriptase or protease tests, deserves further investigation in the treatment of HIV-1-associated dementia.
Assuntos
Fármacos Anti-HIV/farmacologia , HIV/efeitos dos fármacos , Piperazinas/farmacologia , Fator de Ativação de Plaquetas/antagonistas & inibidores , Glicoproteínas da Membrana de Plaquetas/antagonistas & inibidores , Receptores de Superfície Celular , Receptores Acoplados a Proteínas G , Fármacos Anti-HIV/química , Células Cultivadas , HIV/fisiologia , Humanos , Técnicas In Vitro , Concentração Inibidora 50 , Macrófagos/efeitos dos fármacos , Macrófagos/virologia , Testes de Sensibilidade Microbiana , Piperazinas/síntese química , Piperazinas/química , Piridinas/farmacologia , Relação Estrutura-Atividade , Tiazóis/farmacologia , Replicação Viral/efeitos dos fármacosRESUMO
After characterization of a novel odorant-binding protein (OBP) variant isolated from the rat nasal mucus, the corresponding cDNA was cloned by RT-PCR. Recombinant OBP-1F, the sequence of which is close to that of previously reported rat OBP-1, has been secreted by the yeast Pichia pastoris at a concentration of 80 mg.L-1 in a form identical to the natural protein as shown by MS, N-terminal sequencing and CD. We observed that, in contrast with porcine OBP-1, purified recombinant OBP-1F is a homodimer exhibiting two disulfide bonds (C44-C48 and C63-C155), a pairing close to that of hamster aphrodisin. OBP-1F interacts with fluorescent probe 1-aminoanthracene (1-AMA) with a dissociation constant of 0.6 +/- 0. 3 microM. Fluorescence experiments revealed that 1-AMA was displaced efficiently by molecules including usual solvents such as EtOH and dimethylsulfoxide. Owing to the large OBP-1F amounts expressed, we set up a novel biomimetic assay (volatile-odorant binding assay) to study the uptake of airborne odorants without radiolabelling and attempted to understand the odorant capture by OBP in the nasal mucus under natural conditions. The assay permitted observations on the binding of airborne odorants of different chemical structures and odors (2-isobutyl-3-methoxypyrazine, linalool, isoamyl acetate, 1-octanal, 1-octanol, dimethyl disulfide and methyl thiobutyrate). Uptake of airborne odorants in nearly physiological conditions strengthens the role of OBP as volatile hydrophobic odorant carriers in the mucus of the olfactory epithelium through the aqueous barrier towards the chemo-sensory cells.
Assuntos
Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Sequência de Aminoácidos , Animais , Antracenos/farmacologia , Sequência de Bases , Dicroísmo Circular , Clonagem Molecular , Cricetinae , DNA Complementar/metabolismo , Dimetil Sulfóxido/farmacologia , Dissulfetos , Etanol/farmacologia , Ligantes , Espectrometria de Massas , Dados de Sequência Molecular , Mucosa Olfatória/metabolismo , Pichia/metabolismo , Ligação Proteica , Pirazinas/farmacologia , Ratos , Ratos Endogâmicos F344 , Receptores Odorantes/química , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Solventes/farmacologia , Espectrometria de Fluorescência , Fatores de TempoRESUMO
Our present knowledge of the lutropin (LH/hCG) receptor structure derives from deductions made from its amino acid sequence as established by studying the cDNA. To obtain direct experimental information, luteinizing hormone (LH) receptor expressed in L cells was immunopurified in sufficient amounts to warrant analysis by mass spectrometry and microsequencing. The mature receptor, complexed to human chorionic gonadotropin (hCG), was purified by using monoclonal antibodies recognizing the hormone, whereas the mannose-rich non-hormone-binding precursor was purified by use of antireceptor antibodies. Determination of the N-terminus showed that (2)/(3) of protein molecules started at Thr24 whereas (1)/(3) started at Ala28. All these molecules bound hCG, suggesting that the most N-terminal region of the receptor does not participate in hormone binding. Six N-glycosylation sites have been predicted from the amino acid sequence. One of them (Asn299) was found to be nonglycosylated in both the precursor and the mature protein. The most heavily glycosylated residue was Asn291, followed by Asn195 and Asn99. These three sites accounted for 82% and 97% of carbohydrate moieties in the mature receptor and in the mannose-rich precursor, respectively. The presence of some receptor molecules nonglycosylated at sites 99, 174, and 195 in hormone-receptor complexes dismisses a direct role of these glycosylation sites in hormone binding or in the correct folding of the protein. The mature carbohydrate chains were homogeneous at position 174, 195, and 313 (absence of Golgi mannosidase II activity at positions 174 and 313, absence of GlcNAc tranferases III and IV activity at position 195). Heterologous carbohydrates were present at sites 99 and 291. The latter, which is highly variable in carbohydrate chains, is unlikely to participate in a direct interaction with hormone. Site 313 thus remains as the main candidate for a role in hormone binding.
Assuntos
Precursores de Proteínas/química , Processamento de Proteína Pós-Traducional , Receptores do LH/química , Sequência de Aminoácidos , Animais , Sequência de Carboidratos , Gonadotropina Coriônica/metabolismo , Cromatografia Líquida de Alta Pressão , Glicosilação , Células L , Espectrometria de Massas , Camundongos , Dados de Sequência Molecular , Oligossacarídeos/biossíntese , Compostos Organofosforados , Fragmentos de Peptídeos/química , Ligação Proteica , Precursores de Proteínas/isolamento & purificação , Receptores do LH/isolamento & purificação , Análise de Sequência de ProteínaRESUMO
Polyglutamylation is an original posttranslational modification, discovered on tubulin, consisting in side chains composed of several glutamyl units and leading to a very unusual protein structure. A monoclonal antibody directed against glutamylated tubulin (GT335) was found to react with other proteins present in HeLa cells. After immunopurification on a GT335 affinity column, two prominent proteins of approximately 50 kDa were observed. They were identified by microsequencing and mass spectrometry as NAP-1 and NAP-2, two members of the nucleosome assembly protein family that are implicated in the deposition of core histone complexes onto chromatin. Strikingly, NAP-1 and NAP-2 were found to be substrates of an ATP-dependent glutamylation enzyme co-purifying on the same column. We took advantage of this property to specifically label and purify the polyglutamylated peptides. NAP-1 and NAP-2 are modified in their C-terminal domain by the addition of up to 9 and 10 glutamyl units, respectively. Two putative glutamylation sites were localized for NAP-1 at Glu-356 and Glu-357 and, for NAP-2, at Glu-347 and Glu-348. These results demonstrate for the first time that proteins other than tubulin are polyglutamylated and open new perspectives for studying NAP function.