RESUMO
BACKGROUND: The first months of life may represent a vulnerable period in the development of atopic diseases. The objective of this study was to examine the relationship between the month of birth and the development of birch and grass pollen allergy in the Swiss population. METHODS: Data from the Swiss Study on Air Pollution and Lung Diseases in Adults(SAPALDIA) as well as the Swiss Study on Childhood Allergy and Respiratory Symptoms with Respect to Air Pollution and Climate (SCARPOL) were used. A logistic regression was calculated with grass and birch pollen sensitisation (positive skin prick test) or allergy (positive skin prick test and allergic symptoms) as outcome variables and the season of birth as predictor variable. The contribution of the season of birth on pollinosis was further adjusted for well-known risk factors and potential confounding variables. RESULTS: The logistic regression revealed a significant effect of the season of birth on birch pollen sensitisation and an effect of borderline significance on birch pollen allergy, i.e. subjects born in the pollen season (March to April) showed an increased risk of being sensitised/allergic to birch pollen. The results also indicated a tendency towards an increased risk for subjects born in the grass pollen season (May to June) to develop grass pollen allergy. CONCLUSION: Our results support the hypothesis that the first few months of life constitute a sensitive period, during which inhalative exposure to certain allergens may predispose to the subsequent development of atopic respiratory disease.
Assuntos
Parto , Pólen/imunologia , Rinite Alérgica Sazonal/epidemiologia , Rinite Alérgica Sazonal/imunologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Rinite Alérgica Sazonal/diagnóstico , Suíça/epidemiologia , Fatores de TempoRESUMO
Learning and memory formation involve long-term potentiation (LTP) of synaptic strength. A fundamental feature of LTP induction in the brain is the need for coincident pre- and postsynaptic activity. This restricts LTP expression to activated synapses only (homosynaptic LTP) and leads to its input specificity. In the spinal cord, we discovered a fundamentally different form of LTP that is induced by glial cell activation and mediated by diffusible, extracellular messengers, including d-serine and tumor necrosis factor (TNF), and that travel long distances via the cerebrospinal fluid, thereby affecting susceptible synapses at remote sites. The properties of this gliogenic LTP resolve unexplained findings of memory traces in nociceptive pathways and may underlie forms of widespread pain hypersensitivity.
Assuntos
Hiperalgesia/fisiopatologia , Potenciação de Longa Duração/fisiologia , Neuroglia/fisiologia , Nociceptividade/fisiologia , Animais , Líquido Cefalorraquidiano/metabolismo , Hiperalgesia/metabolismo , Masculino , Memória/fisiologia , Plasticidade Neuronal/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores Purinérgicos P2X7/metabolismo , Serina/metabolismo , Transdução de Sinais , Medula Espinal/citologia , Medula Espinal/fisiologia , Sinapses/fisiologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
We report the case of a pneumothorax caused by the improper placement of a nasogastric feeding tube in a tracheostomized patient after bilateral lung transplantation. We discuss the contribution of low-pressure cuffed tracheostomy tubes to the inadvertent respiratory tract misplacement of a nasogastric feeding tube, as well as the problems of nasogastric feeding tube insertion in the sedated patient, why the previously installed closed-tube thoracostomy did not prevent the pneumothorax and possible pitfalls in confirming the proper position of the nasogastric feeding tube. In conclusions, we stress that in high risk patients a nasogastric feeding tube should only be inserted under direct vision and that a subsequent routine X-ray is mandatory for confirming proper positioning.
Assuntos
Intubação Gastrointestinal/efeitos adversos , Transplante de Pulmão , Erros Médicos/efeitos adversos , Pneumotórax/etiologia , Traqueostomia , Humanos , Intubação Gastrointestinal/métodos , Masculino , Pessoa de Meia-Idade , Pneumotórax/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
The primary objective of the study was to determine the impact of the identity of the respondent (parents versus adolescents) on prevalence estimates of asthma symptoms in Swiss adolescents. In addition, factors influencing agreement between parents' and adolescents' responses to the same questions were analysed. One thousand three hundred and seventy-four (78.4%) adolescents, aged 14 years, self-completed a questionnaire at school based on the International Study of Asthma and Allergy in Childhood (ISAAC) core questions on wheezing and asthma. The same questions were incorporated into a questionnaire to be completed by the parents at home. The adolescents' self-reported prevalence rates of current asthma symptoms and "asthma ever" were significantly higher than those obtained from the parental questionnaires. 856 (62.6%) parental questionnaires were filled in by parents without the help of the adolescents, 460 (37.4%) were completed by parents and adolescents and 51 (3.7%) were completed by the adolescents without the parents. Prevalence rates were higher when parents and adolescents completed the questionnaire jointly than when questionnaires were completed by parents alone. The level of agreement between parental and self-completed questionnaires was moderate to low (kappa coefficients 0.22-0.68). Agreement between parental and adolescents reports of asthma symptoms was best when questionnaires were completed jointly by parents and adolescents, when the adolescent was a girl, when a family history of asthma was recorded, when the adolescent was a non-smoker, and when the parental education was high. We conclude that the higher reporting of prevalence rates of current asthma symptoms by adolescents compared to reporting by their parents demonstrates the need to take the respondent to a questionnaire into account when comparisons are made between prevalence studies. The results also suggest that factors related to the family milieu influence symptom reporting.
Assuntos
Asma/epidemiologia , Adolescente , Asma/genética , Tosse/epidemiologia , Escolaridade , Feminino , Humanos , Masculino , Relações Pais-Filho , Pais , Esforço Físico/fisiologia , Prevalência , Reprodutibilidade dos Testes , Sons Respiratórios/genética , Autoavaliação (Psicologia) , Sensibilidade e Especificidade , Fatores Sexuais , Fumar/epidemiologia , Inquéritos e Questionários , Suíça/epidemiologiaRESUMO
The work input of an institutional review board, the satisfaction or dissatisfaction of project applicants with its decisions, as well as the amount of time needed for preparatory and follow-up work for projects submitted to the board were surveyed in a questionnaire. An analysis of the status quo provided proposals for improvement, with the aim of increasing the satisfaction of all parties involved. Questionnaires were returned by 41.4% (101/244) of the specialist doctors surveyed. Of these, 42 were doctors who had submitted projects for review and whose evaluation was used for the study. The proportion of trained "clinical review doctors" was 14.3%. Analysis of work input showed that 13.5 +/- 15.2 hours were invested before submitting a project and 6.3 +/- 9.3 hours in the follow-up. Although the board's work was given a satisfactory grading with a score of 2.8 +/- 1.0, the surveyed satisfaction/importance profile showed marked deficits in many areas, primarily in organization and communication, as well as in the examination and evaluation of projects. The suggestions for improvement above all requested the introduction of a review system employing specialists from outside the institution or from other disciplines, standardization of project submission, optimization of organization and improvement in communication. In summary, the institutional review board plays an important role in clinical research. The acceptance of a review board's work, however, can only be improved when the suggestions for improvement are realized step by step. The results of this evaluation and the proposed solutions can also help other boards improve their work. At any rate, it would be desirable to take a new look in several years' time at how the proposals worked out in this study have been implemented.
Assuntos
Comissão de Ética , Corpo Clínico Hospitalar , Áustria , Hospitais Comunitários , Inquéritos e QuestionáriosRESUMO
Is the increased incidence of allergic diseases a by-product of technologic development? Can this hypothesis be supported by measurable alterations in immunoreactivity? Continuous sero-epidemiologic monitoring since 1983 in children from Grabs prove a statistically significant increase in allergic sensitization, in particular against grass pollen. An etiologic link between the increased prevalence of hay fever and growing volume of motor vehicle traffic is suggested by: 1. the temporal correlation: Prevalence of hay fever has increased simultaneously with the raise of emission of photo-oxidants. High ozone and pollen immissions do also coincide over the course of the day. 2. pathophysiology: Ozone prolongs and intensifies exposure to allergens by reducing bronchociliary clearance and increasing permeability for inhaled antigens. Children from farmers exhibit a lower morbidity for hay fever in spite of a more intense exposure to both photo-oxidants and grass pollen. They show that not only exposure but also adaptive mechanisms may be important in assessing correlations with aerial pollutants.
Assuntos
Poluentes Atmosféricos/efeitos adversos , Hipersensibilidade/etiologia , Imunidade , Criança , Humanos , Hipersensibilidade/imunologia , Conceitos Meteorológicos , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Pólen/imunologia , Rinite Alérgica Sazonal/imunologiaRESUMO
BACKGROUND: Nerve injury leads to Aß-fibre-mediated mechanical allodynia that is in part due to an impaired GABAergic inhibition in the spinal cord dorsal horn. The properties and function of GABAergic neurons in spinal cord lamina III, an area where low-threshold mechanosensitive Aß-fibres terminate are, however, largely unknown. METHODS: We used transgenic mice, which express enhanced green fluorescent protein (EGFP) under control of the promoter GAD67. The morphology and neurochemical characteristics of GABAergic, EGFP-expressing neurons were characterized. We assessed active and passive membrane properties of spinal lamina III GABAergic neurons in naïve animals and animals with a chronic constriction injury (CCI) of the sciatic nerve. RESULTS: EGFP-expressing neurons in lamina III were predominantly islet cells (47%), whereas non-EGFP-expressing neurons were largely inverted stalked cells (40%). EGFP-expressing neurons accounted for about 25% of GABAergic neurons in lamina III. Forty-four percent co-expressed glycine, 10% neuronal nitric oxide synthase and 3% co-expressed parvalbumin. We found costaining with protein kinase CßII in 42% of EGFP-expressing neurons but no expression of protein kinase Cγ. Membrane properties and excitability of EGFP-and non-EGFP-expressing neurons from naïve and neuropathic animals were indistinguishable. The most frequent firing pattern was tonic firing (naïve: 35%, neuropathic: 37%) followed by gap firing (naïve: 33%, neuropathic: 25%). Delayed, initial burst and single-spike firing patterns made up the remainder in both groups. CONCLUSION: A change in membrane excitability or discharge pattern of this group of lamina III GABAergic neurons is unlikely the cause for mechanical allodynia in animals with CCI.
Assuntos
Neurônios GABAérgicos/metabolismo , Hiperalgesia/fisiopatologia , Neuralgia/metabolismo , Doenças do Sistema Nervoso Periférico/metabolismo , Medula Espinal/metabolismo , Medula Espinal/fisiopatologia , Potenciais de Ação/fisiologia , Animais , Hiperalgesia/metabolismo , Camundongos , Camundongos Transgênicos , Neuralgia/fisiopatologia , Doenças do Sistema Nervoso Periférico/fisiopatologiaAssuntos
Fosfoenolpiruvato , Fosfotransferases , Aminoácidos/análise , Sítios de Ligação , Eletroforese em Gel de Poliacrilamida , Histidina , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Fosfoenolpiruvato/farmacologia , Fosfoproteínas , Fosfotransferases/metabolismo , Ligação Proteica , Conformação Proteica , Staphylococcus/enzimologiaAssuntos
Doenças Transmissíveis/epidemiologia , Adolescente , Criança , Humanos , Imunização , Sarampo/epidemiologia , Sarampo/prevenção & controle , Caxumba/epidemiologia , Caxumba/prevenção & controle , Rubéola (Sarampo Alemão)/epidemiologia , Rubéola (Sarampo Alemão)/prevenção & controle , População Rural , SuíçaRESUMO
BACKGROUND: Changing occurrence rates of asthma, allergic rhinitis and atopic dermatitis are of public health concern and require surveillance. Changes in prevalence rates of these atopic diseases were monitored during 10 years and their trend with time was determined taking into account the influence of personal and environmental risk factors. METHODS: Four cross-sectional surveys in 5-7-year old children were performed in seven different communities in Switzerland between 1992 and 2001. Prevalence of respiratory and allergic symptoms and of affecting risk factors including parental environmental concern were assessed using a standardized parental questionnaire. RESULTS: A total of 988 (74.1%), 1778 (79.0%), 1406 (82.6%) and 1274 (78.9%) children participated, respectively, in the 1992, 1995, 1998 and 2001 surveys. Prevalence rates of asthma and hay fever symptoms remained quite stable over time (wheeze/past year: 8.8%, 7.8%, 6.4% and 7.4%, sneezing attack during pollen season: 5.0%, 5.6%, 5.4% and 4.6%). Rates of reported atopic dermatitis symptoms (specific skin rash/past year: 4.6%, 6.5%,7.4% and 7.6%) showed an increase over time, but those of diagnosis of eczema did not show a clear pattern (18.4%, 15.7%, 14.0% and 15.2%). Stratified analysis by parental environmental concern and by parental atopy showed similar trends. Rates of atopic dermatitis symptoms showed significant increase in girls but stayed stable in boys. CONCLUSION: Results of these four consecutive surveys suggest that the increase in prevalence of asthma and hay fever in 5-7-year old children living in Switzerland may have ceased. However, symptoms of atopic dermatitis may still be on the rise, especially among girls.
Assuntos
Asma/epidemiologia , Dermatite Atópica/epidemiologia , Rinite Alérgica Sazonal/epidemiologia , Criança , Pré-Escolar , Comorbidade , Estudos Transversais , Feminino , Inquéritos Epidemiológicos , Humanos , Masculino , Prevalência , Fatores de Risco , Fatores Sexuais , Inquéritos e Questionários , Suíça/epidemiologia , Fatores de TempoRESUMO
Thanks to enormous progress in industrial medicine, life expectancy of workers in dust-polluted (dust-burdened) jobs has massively improved; however, farmers, gained too little interest of industrial medicine so far and thus show one of the highest mortality rates from pulmonary diseases. Today the farmer's exposure to dust and respective allergens is often extremely high; however, the composition of the inhaled dust varies extremely, depending on the type of work. Particularly organic dusts are inhaled that are known as common and frequent allergy inducers in the normal population. In spite of the increased exposure to the common airborne allergens, children of farmers rarely develop allergies, obviously due to an increased tolerance to common allergens. The high mortality rate from pulmonary diseases, including asthma, in farmers seems therefore less a question of profession-specific allergens than of decompensated adaptation phenomena. Thus an optimized dust prevention seems important. Dermatologic diseases: Farmers are exposed to many irritative and potentially sensitizing contact allergens including those from natural sources (plants) and diverse fungicides, pesticides as well as chemicals used in mechanical professions. The risk of phototoxic and photoallergic reactions is increased by profession-related exposure to sun. This also concerns related reactions to medical drugs. The best preventive measure for contact sensitization is an optimized skin protection, particularly of the hands.
Assuntos
Doenças dos Trabalhadores Agrícolas/etiologia , Hipersensibilidade/etiologia , Pneumoconiose/etiologia , Doenças dos Trabalhadores Agrícolas/prevenção & controle , Alérgenos , Criança , Dermatite de Contato/etiologia , Poeira/efeitos adversos , Exposição Ambiental , Humanos , Estilo de Vida , Transtornos de Fotossensibilidade/etiologiaRESUMO
8 subjects with costovertebral dysplasia in 4 interrelated families are described. The cases occurred from 1949 to 1978 and all showed the analogous generalized malformation of the vertebrae and ribs. One child with concomitant chromosomal anomaly (Down's syndrome) died at the age of 7 days. Follow-up in the 7 cases shows no decrease in life expectancy or any other malformation, and in particular non bronchopneumonial complications. Case reports and comparisons of the prevalence of neural tube defects in this isolated population and in Switzerland rule out increased risk of neural tube defects for costovertebral dysplasia. The pedigree of kindred over 8 generations is consistent with autosomal recessive inheritance. As the cause of the malformation a possible receptor defect of the mesodermal sclerotomes is discussed.
Assuntos
Anormalidades Múltiplas/genética , Costelas/anormalidades , Coluna Vertebral/anormalidades , Anormalidades Múltiplas/diagnóstico por imagem , Anormalidades Múltiplas/etiologia , Adulto , Criança , Diagnóstico Diferencial , Feminino , Genes Recessivos , Humanos , Recém-Nascido , Masculino , Linhagem , Radiografia , Costelas/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , SuíçaRESUMO
During the period 1988-1992 deaths from lung diseases were more frequent among the farming population according to Swiss mortality data. The age-standardized proportional mortality rate (PMR) is 127 for all the lung diseases (ICD-8 460-519), 140 for bronchitis and asthma (ICD-8 490-493), 137 for asthma alone (ICD-8 493) and 841 for pneumoconiosis due to organic dust (ICD-8 516.1 + .2). Stock-farmers showed a mortality pattern for chronic obstructive pulmonary disease opposite to that of vegetable farmers and wine-growers. This increased mortality among farmers is paradoxical in the light of the more frequent tolerance for aeroallergens among the children of farmers, the conservative style of housing and living as well as received ideas about working in natural and therefore healthy air. Insufficient knowledge of the multifactorial risks of natural pathogenic organic substances and of dangerous work are just as important for the pathogenesis of these diseases and deaths as the changed social and cultural values with the consequences on insurance policy. These factors affect optimal prophylaxis (limitation of air pollution, safety measures, job change and measures in order to achieve adequate social security).
Assuntos
Doenças dos Trabalhadores Agrícolas/mortalidade , Doenças Respiratórias/mortalidade , Adulto , Idoso , Poluentes Ocupacionais do Ar/toxicidade , Asma/mortalidade , Bronquite/mortalidade , Feminino , Humanos , Pneumopatias Obstrutivas/mortalidade , Masculino , Pessoa de Meia-Idade , Pneumoconiose/mortalidade , Hipersensibilidade Respiratória/mortalidade , Fatores de Risco , Suíça/epidemiologiaRESUMO
Because of their increased environmental resistance faecal streptococci are a good indicator of a contamination dating back a long time. Under the new Federal German Drinking Water Regulations, examination of faecal streptococci is not mandatory. On the basis of 190 samples of water from natural springs it was shown that, if the water was examined only in respect of E. coli and coliform bacteria there were no objections in 22% of water that was faecally contaminated, so that such water escaped detection. Hence, it is advisable to perform the faecal streptococci test in water that is frequently or potentially infected with bacteria.
Assuntos
Enterococcus faecalis/isolamento & purificação , Microbiologia da Água , Abastecimento de Água/normas , Contagem de Colônia Microbiana , Fezes/microbiologia , HumanosRESUMO
10 children aged 15 years, who presented with anti-mumps antibodies of < 3 PEI (Paul Ehrlich Institute) despite documented mumps vaccination in the past, were boosted with Triviraten Berna (Rubini mumps strain) and the antibody response was assessed after 7, 28 and 90 days. All 5 children boosted with the same vaccine (Rubini mumps strain) had a titer rise as early as day 7 persisting for 3 months. The 4 children primed with the Jeryl Lynn mumps strain showed a primary immune response, i.e. a rise of the antibody titer after 28 days only, which did not persist well. The child originally primed with the Urabe mumps strain did not show any significant immune response on day 28, which means a negative result. Children apparently susceptible to mumps cannot be differentiated from immune children by measurement of antibody titers. Reexposure to the homologous vaccine virus elicited a persisting immune response: however, revaccination with a heterologous vaccine virus elicited an immune response directed against different antigenic epitopes, followed by limited persistence of circulating antibodies. The efficacy of a second dose of mumps vaccine was demonstrated in 9/10 children. Only by using a two-dose immunization schedule is it possible to effectively avoid the occasionally serious complications of this viral infection, as has been achieved in Finland.
Assuntos
Imunização Secundária , Vacina contra Caxumba , Caxumba/prevenção & controle , Adolescente , Anticorpos Antivirais/isolamento & purificação , Epitopos , Humanos , Vírus da Caxumba/imunologia , Fatores de TempoRESUMO
50 trampers in India and Sri Lanka were studied in a semistructured interview by a questionnaire for socio-demographic data, for their medical and psychiatric history and their drug-experience. The MPI (Eysenck) and SSS (Zuckermann) were applied as tests for describing personality. Most of the trampers are around 25 years, stem from medium economical strata, have an education of high school or university. Nearly all of them are experienced drug-users (mainly hashish), most of them for long time without increase of intake and without bodily or mental or social deterioration. In the MPI the score for extraversion and neuroticism is within the (English) norm rage. Female probands showed a higher score of neuroticism than males. The total score in the SSS was significantly higher than in the standard population, mainly due to significantly elevated scores in the scale for disinhibition and boredom susceptibility.
Assuntos
Transtornos da Personalidade/psicologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Migrantes/psicologia , Adulto , Feminino , Humanos , Índia , MMPI , Masculino , Fatores Socioeconômicos , Sri Lanka , ViagemRESUMO
In 1982, one of us reported a cluster of eight individuals affected by spondylocostal dysostosis (SD, MIM 277300) in four nuclear families indigenous to a village from eastern Switzerland. We tested the hypothesis that the molecular basis for this cluster was segregation of a single mutation in the DLL3 gene, recently linked to SD. Marker haplotypes around the DLL3 locus contradicted this hypothesis as three different haplotypes were seen in affected individuals, but sequence analysis showed that three unreported DLL3 mutations were segregating: a duplication of 17 bp in exon 8 (c.1285-1301dup), a single-nucleotide deletion in exon 5 (c.615delC), and a R238X nonsense mutation in exon 6. Contrary to our initial assumption of a single allele segregating in this small community, three different pathogenic alleles were observed, with a putative founder mutation occurring at the homozygous state but also compounding with, and thus revealing, two other independent mutations. As all three mutations predict truncation of the DLL3 protein and loss of the membrane-attaching domain, the results confirm that autosomal recessive spondylocostal dysostosis represents the null phenotype of DLL3, with remarkable phenotypic consistency across families.
Assuntos
Disostoses/genética , Proteínas de Membrana/genética , Feminino , Efeito Fundador , Genes Recessivos , Ligação Genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Mutação , Linhagem , Estrutura Terciária de Proteína , Radiografia , Costelas/anormalidades , Costelas/diagnóstico por imagem , Análise de Sequência de DNA , Coluna Vertebral/anormalidades , Coluna Vertebral/diagnóstico por imagemRESUMO
UNLABELLED: Laparoscopy is a surgical technique for a growing variety of abdominal operations. In patients undergoing this procedure, arterial blood oxygenation and hemodynamics are frequently depressed. This study evaluated the effect of different levels of positive end-expiratory pressure (PEEP) during intraperitoneal CO(2) insufflation on the lung's ventilation-perfusion distribution in a porcine model. We studied 13 anesthetized pigs with an intraperitoneal pressure of 15 cm H(2)O applied at either incremental values of PEEP (5-20 cm H(2)O, increments of 5 cm H(2)O) or a constant PEEP of 5 cm H(2)O. The effects of CO(2) pneumoperitoneum on inert gas exchange and hemodynamics were examined with the multiple inert gas elimination technique. During pneumoperitoneum, gas exchange was most augmented by 15 and 20 cm H(2)O of PEEP. Although the differences in hemodynamics between the individual settings were insignificant, 10 cm H(2)O of PEEP provided the smallest impairment of hemodynamics. We conclude that PEEP of 15 H(2)O during pneumoperitoneum resulted in a modest hemodynamic depression but significant gas exchange augmentation in our experiment. IMPLICATIONS: Anesthetized pigs, with a pneumoperitoneum of 15 cm H(2)O, were treated either with incremental values of positive end-expiratory pressure (5-20 cm H(2)O, increments of 5 cm H(2)O) or with a constant positive end-expiratory pressure of 5 cm H(2)O. Fifteen and 20 cm H(2)O resulted in significantly improved pulmonary gas exchange compared with 5 cm H(2)O.
Assuntos
Pneumoperitônio Artificial/métodos , Respiração com Pressão Positiva , Animais , Gasometria , Dióxido de Carbono/sangue , Oxigênio/sangue , Circulação Pulmonar , Troca Gasosa Pulmonar , Respiração Artificial , Testes de Função Respiratória , Suínos , Fatores de TempoRESUMO
The phosphocarrier protein HPr has been investigated by proton nuclear magnetic resonance (NMR) at 270 MHz in order to evaluate structural properties of the whole molecule and its active site. The titration behaviour of the three tyrosines of the HPr protein was analysed by monitoring the chemical shifts of the aromatic proton resonances of these residues as a function of pH. It was found that the HPr protein contains a lot of slowly exchanging NH backbone protons which suggested a relatively rigid secondary structure of the protein molecule itself although it contains no disulfide bridges. The HPr protein shows a sharp reversible denaturation behaviour at alkaline pH values. Between pH 10.8 and 11.1 two C-2 proton resonance peaks for the single histidine residue could be observed together with abrupt changes in the aromatic and aliphatic absorption region of the HPr protein which are due to chemical exchange processes. The NMR spectrum of the HPr protein is only changed a little upon raising the temperature from 14 degrees C to 70 degrees C. At 76 degrees C all resonances in the spectrum broaden and almost disappear. This process is irreversible.
Assuntos
Proteínas de Transporte , Fosfatos/metabolismo , Fosfoproteínas , Fosfotransferases , Staphylococcus aureus/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Análise de Fourier , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Fosfoenolpiruvato/farmacologia , Fosfoproteínas/metabolismo , Fosfotransferases/metabolismo , Conformação Proteica , Desnaturação Proteica , Tirosina/análiseRESUMO
A formalism based on the theory of Markov processes and suitable for the analysis of multiple internal motions in macromolecules is presented. Computer calculations of specific motional models for (13)C nuclear magnetic resonance (NMR) relaxation, treated as special cases of the proposed formalism, demonstrate the potential of this approach for discriminating between different motional models on the basis of NMR relaxation data.