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1.
Nat Commun ; 12(1): 6217, 2021 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-34728617

RESUMEN

Natural sounds, and bird song in particular, play a key role in building and maintaining our connection with nature, but widespread declines in bird populations mean that the acoustic properties of natural soundscapes may be changing. Using data-driven reconstructions of soundscapes in lieu of historical recordings, here we quantify changes in soundscape characteristics at more than 200,000 sites across North America and Europe. We integrate citizen science bird monitoring data with recordings of individual species to reveal a pervasive loss of acoustic diversity and intensity of soundscapes across both continents over the past 25 years, driven by changes in species richness and abundance. These results suggest that one of the fundamental pathways through which humans engage with nature is in chronic decline, with potentially widespread implications for human health and well-being.


Asunto(s)
Acústica , Aves/fisiología , Vocalización Animal/fisiología , Animales , Biodiversidad , Aves/clasificación , Conservación de los Recursos Naturales , Europa (Continente) , Humanos , América del Norte , Dinámica Poblacional , Estaciones del Año , Sonido , Vocalización Animal/clasificación
2.
Phys Rev Lett ; 126(24): 242301, 2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34213947

RESUMEN

Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150-350 MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma's final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities.

3.
Spine J ; 21(8): 1332-1339, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33831545

RESUMEN

BACKGROUND CONTEXT: Spine patients have a higher rate of depression then the general population which may be caused in part by levels of pain and disability from their spinal disease. PURPOSE: Determination whether improvements in health-related quality of life (HRQOL) resulting from successful spine surgery leads to improvements in mental health. STUDY DESIGN/SETTING: The Canadian Spine Outcome Research Network prospective surgical outcome registry. OUTCOME MEASURES: Change between preoperative and postoperative SF12 Mental Component Score (MCS). Secondary outcomes include European Quality of Life (EuroQoL) Healthstate, SF-12 Physical Component Score (PCS), Oswestry Disability Index (ODI), Patient Health Questionaire-9 (PHQ9), and pain scales. METHODS: The Canadian Spine Outcome Research Network registry was queried for all patients receiving surgery for degenerative thoracolumbar spine disease. Exclusion criteria were trauma, tumor, infection, and previous spine surgery. SF12 Mental Component Scores (MCS) were compared between those with and without significant improvement in postoperative disability (ODI) and secondary measures. Multivariate analysis examined factors predictive of MCS improvement. RESULTS: Eighteen hospitals contributed 3222 eligible patients. Worse ODI, EuroQoL, PCS, back pain and leg pain correlated with worse MCS at all time points. Overall, patients had an improvement in MCS that occurred within 3 months of surgery and was still present 24 months after surgery. Patients exceeding Minimally Clinically Important Differences in ODI had the greatest improvements in MCS. Major depression prevalence decreased up to 48% following surgery, depending on spine diagnosis. CONCLUSIONS: Large scale, real world, registry data suggests that successful surgery for degenerative lumbar disease is associated with reduction in the prevalence of major depression regardless of the specific underlaying diagnosis. Worse baseline MCS was associated with worse baseline HRQOL and improved postoperatively with coincident improvement in disability, emphasizing that mental wellness is not a static state but may improve with well-planned spine surgery.


Asunto(s)
Salud Mental , Calidad de Vida , Canadá , Evaluación de la Discapacidad , Humanos , Vértebras Lumbares , Estudios Prospectivos , Resultado del Tratamiento
5.
Spinal Cord ; 55(6): 618-623, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28418395

RESUMEN

STUDY DESIGN: Retrospective analysis of a prospective registry and surgeon survey. OBJECTIVES: To identify surgeon opinion on ideal practice regarding the timing of decompression/stabilization for spinal cord injury and actual practice. Discrepancies in surgical timing and barriers to ideal timing of surgery were explored. SETTING: Canada. METHODS: Patients from the Rick Hansen Spinal Cord Registry (RHSCIR, 2004-2014) were reviewed to determine actual timing of surgical management. Following data collection, a survey was distributed to Canadian surgeons, asking for perceived to be the optimal and actual timings of surgery. Discrepancies between actual data and surgeon survey responses were then compared using χ2 tests and logistic regression. RESULTS: The majority of injury patterns identified in the registry were treated operatively. ASIA Impairment Scale (AIS) C/D injuries were treated surgically less frequently in the RHSCIR data and surgeon survey (odds ratio (OR)= 0.39 and 0.26). Significant disparities between what surgeons identified as ideal, actual current practice and RHSCIR data were demonstrated. A great majority of surgeons (93.0%) believed surgery under 24 h was ideal for cervical AIS A/B injuries and 91.0% for thoracic AIS A/B/C/D injuries. Definitive surgical management within 24 h was actually accomplished in 39.0% of cervical and 45.0% of thoracic cases. CONCLUSION: Ideal surgical timing for traumatic spinal cord injury (tSCI) within 24 h of injury was identified, but not accomplished. Discrepancies between the opinions on the optimal and actual timing of surgery in tSCI patients suggest the need for strategies for knowledge translation and reduction of administrative barriers to early surgery.


Asunto(s)
Procedimientos Neuroquirúrgicos , Traumatismos de la Médula Espinal/epidemiología , Traumatismos de la Médula Espinal/cirugía , Tiempo de Tratamiento , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Canadá/epidemiología , Vértebras Cervicales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neurocirujanos , Estudios Prospectivos , Sistema de Registros , Estudios Retrospectivos , Encuestas y Cuestionarios , Vértebras Torácicas , Adulto Joven
6.
Phys Rev Lett ; 115(13): 132301, 2015 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-26451547

RESUMEN

We investigate the consequences of a nonzero bulk viscosity coefficient on the transverse momentum spectra, azimuthal momentum anisotropy, and multiplicity of charged hadrons produced in heavy ion collisions at LHC energies. The agreement between a realistic 3D hybrid simulation and the experimentally measured data considerably improves with the addition of a bulk viscosity coefficient for strongly interacting matter. This paves the way for an eventual quantitative determination of several QCD transport coefficients from the experimental heavy ion and hadron-nucleus collision programs.

7.
Eur J Pain ; 18(8): 1103-11, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24449521

RESUMEN

BACKGROUND: A 50% reduction in pain intensity difference (50%PID) between baseline and follow-up evaluation is commonly accepted as adequate pain relief in emergency departments (EDs). However, 50%PID seems to be problematic with the 11-point numerical rating scale (NRS) since even baseline values are more divisible by 2 (50% reduction) than odd baseline values. This study evaluated the impact of this bias and integrated time between baseline and follow-up measurements, hypothesizing that the slope of relative pain intensity difference (SRPID) is a more accurate gauge of pain relief that can decrease bias and incorporate the time component of pain relief. METHODS: A post-hoc analysis of real-time data on an adult population from an urban ED identified 3199 consecutive patients who received an analgesic, had baseline NRS > 3 and a follow-up NRS within 2 h. Primary outcome was the percentage of patients with pain relieved from the 50%PID and the 50%SRPID criteria. RESULTS: Results showed that with 50%PID, even pain intensity levels on baseline NRS comprised a higher percentage of patients [60.7%; 95% confidence interval (CI): 58.8-63.0] with pain relief compared to odd pain intensity levels (51.7%; 95% CI: 48.8-54.6; p < 0.001), underestimating pain-relieved patients by 9% [95% CI: 0.05-0.13; effect size (ES) = 0.09]. The percentage of pain-relieved subjects with the 50%SRPID criteria was not affected by baseline NRS values (59.7% for whole sample; 95% CI: 58.0-61.4; ES = 0.02). CONCLUSIONS: The 50%PID method with an 11-point NRS for assessing adequate pain relief is significantly biased for specific baseline pain intensity level. In the particular context of ED acute pain, the SRPID seems less biased.


Asunto(s)
Dolor Agudo/diagnóstico , Analgésicos/uso terapéutico , Dimensión del Dolor/métodos , Dolor Agudo/tratamiento farmacológico , Adulto , Anciano , Servicio de Urgencia en Hospital , Femenino , Humanos , Masculino , Persona de Mediana Edad , Manejo del Dolor , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
8.
Transl Psychiatry ; 4: e347, 2014 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-24448209

RESUMEN

Sleep is critical for normal brain function and mental health. However, the molecular mechanisms mediating the impact of sleep loss on both cognition and the sleep electroencephalogram remain mostly unknown. Acute sleep loss impacts brain gene expression broadly. These data contributed to current hypotheses regarding the role for sleep in metabolism, synaptic plasticity and neuroprotection. These changes in gene expression likely underlie increased sleep intensity following sleep deprivation (SD). Here we tested the hypothesis that epigenetic mechanisms coordinate the gene expression response driven by SD. We found that SD altered the cortical genome-wide distribution of two major epigenetic marks: DNA methylation and hydroxymethylation. DNA methylation differences were enriched in gene pathways involved in neuritogenesis and synaptic plasticity, whereas large changes (>4000 sites) in hydroxymethylation where observed in genes linked to cytoskeleton, signaling and neurotransmission, which closely matches SD-dependent changes in the transcriptome. Moreover, this epigenetic remodeling applied to elements previously linked to sleep need (for example, Arc and Egr1) and synaptic partners of Neuroligin-1 (Nlgn1; for example, Dlg4, Nrxn1 and Nlgn3), which we recently identified as a regulator of sleep intensity following SD. We show here that Nlgn1 mutant mice display an enhanced slow-wave slope during non-rapid eye movement sleep following SD but this mutation does not affect SD-dependent changes in gene expression, suggesting that the Nlgn pathway acts downstream to mechanisms triggering gene expression changes in SD. These data reveal that acute SD reprograms the epigenetic landscape, providing a unique molecular route by which sleep can impact brain function and health.


Asunto(s)
Corteza Cerebral/metabolismo , Metilación de ADN/fisiología , Genoma/genética , Plasticidad Neuronal/genética , Privación de Sueño/metabolismo , Transcriptoma/genética , Animales , Moléculas de Adhesión Celular Neuronal/genética , Corteza Cerebral/fisiopatología , Metilación de ADN/genética , Electroencefalografía , Epigénesis Genética/genética , Epigénesis Genética/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Privación de Sueño/fisiopatología , Fases del Sueño/genética , Fases del Sueño/fisiología
9.
Rev Mal Respir ; 23(3 Pt 1): 265-8, 2006 Jun.
Artículo en Francés | MEDLINE | ID: mdl-16788527

RESUMEN

INTRODUCTION: Isolated splenic metastases from a bronchial carcinoma, without other visceral metastatic involvement, are exceptionally uncommon. CASE REPORT: The authors report the finding of an isolated splenic metastasis 21 months after a left pneumonectomy for an undifferentiated large cell carcinoma, initially staged pT3N1M0. The splenic metastasis presented as a major deterioration in general health and sharp pains in the left hypochondrium. Splenectomy confirmed the metastatic nature of the splenic tumour and relieved the severe abdominal pains. Two years after the splenectomy and with out adjuvant treatment the patient remains in complete remission. CONCLUSION: Splenectomy for a metastasis from a bronchial carcinoma should avoid the later complications of this type of metastasis: severe abdominal pain, splenic rupture and compression of neighbouring vessels. If the bronchial carcinoma is controlled locally and the splenic metastasis is isolated, splenectomy offers, perhaps, a further chance of prolonged survival.


Asunto(s)
Carcinoma de Células Grandes/patología , Neoplasias Pulmonares/patología , Neoplasias del Bazo/secundario , Anciano , Humanos , Masculino , Esplenectomía , Neoplasias del Bazo/diagnóstico , Neoplasias del Bazo/cirugía
10.
Neurology ; 62(1): 46-50, 2004 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-14718696

RESUMEN

OBJECTIVE: To measure the effect of age on Multiple Sleep Latency Test (MSLT)characteristics, sleep latency, and number of sleep-onset REM periods (SOREMP) in two large populations of narcoleptic patients with similar genetic backgrounds. METHODS: Clinical and polygraphic information on the severity of the condition was obtained on 236 well-defined narcolepsy-cataplexy-human leukocyte antigen DR2-positive patients from Montpellier (France) and on 147 similar patients from Montreal (Canada). RESULTS: The results show a progressive decrease in the number of SOREMP with age and a progressive increase in the mean sleep latency on the MSLT as a function of age. This finding is also related to the severity of cataplexy as assessed from the clinical history with a progressive decrease in the frequency of cataplexy attacks with age. These results may reflect the progressive increase in sleep latency seen in normal aging and suggest that clinical improvement might be due to changes in the neural mechanisms responsible for SOREMP, which may weaken with age. CONCLUSIONS: The progressive decrease in the number of SOREMP and increase in the mean sleep latency on the MSLT as a function of age suggest that the current criteria used for diagnosis may be too stringent in older patients. The major influence of age on MSLT results should therefore be taken into account when diagnosing a narcoleptic patient.


Asunto(s)
Técnicas de Diagnóstico Neurológico/estadística & datos numéricos , Narcolepsia/diagnóstico , Adolescente , Adulto , Distribución por Edad , Factores de Edad , Edad de Inicio , Anciano , Canadá/epidemiología , Niño , Preescolar , Estudios de Cohortes , Comorbilidad , Femenino , Francia/epidemiología , Antígeno HLA-DR2/sangre , Alucinaciones/diagnóstico , Alucinaciones/epidemiología , Alucinaciones/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Narcolepsia/epidemiología , Narcolepsia/fisiopatología , Polisomnografía , Índice de Severidad de la Enfermedad , Distribución por Sexo , Factores Sexuales , Parálisis del Sueño/diagnóstico , Parálisis del Sueño/epidemiología , Parálisis del Sueño/fisiopatología , Factores de Tiempo
11.
Rev Neurol (Paris) ; 159(8-9): 786-9, 2003 Sep.
Artículo en Francés | MEDLINE | ID: mdl-13679722

RESUMEN

The objective of this study was to analyse stabilized gait disorders in newly diagnozed Parkinson patients using an accelerometric device, which had been previously validated for human locomotion analysis (Auvinet et al., 1999), and to compare Parkinson's gait variables with those obtained in a matched normal population (same gender, age, height and weight). The patient group included 22 subjects (women: 9, men: 13; age: 69+/-9 y; height: 164+/-9 cm; weight: 71+/-15 kg) with motor score from 4 to 59 (mean: 23.5+/-3.0). Gait analysis system included two accelerometers held over the middle of the low back by means of a semi-elastic belt, cranio-caudal and side to side accelerations were recorded at a frequency of 50 Hz. Subjects were asked to walk at their own speed along a straight 40 meter long corridor. A 20 second period of stabilized walking was used to calculate stride frequency, step symmetry, stride regularity and cranio-caudal activity (related to hypokinesia). The walking speed was measured with an electronic stop watch. Parkinson's gait was characterized by a reduction of walking velocity (p<0.0001) which was explained by reduction of stride frequency (p<0.001) and step length (p<0.001), but mainly we noticed a reduction of walking regularity (p<0.0001) and of the cranio-caudal activity (p<0.0001). These two last variables were strongly correlated to the motor score ((r=-0.59 (p<0.01); r=-0.65 (p<0.003), respectively)). In conclusion regularity and cranio-caudal activity appeared as the most interesting variables to characterize stabilized Parkinson's gait.


Asunto(s)
Equipo para Diagnóstico , Trastornos Neurológicos de la Marcha/etiología , Trastornos Neurológicos de la Marcha/fisiopatología , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/fisiopatología , Anciano , Anciano de 80 o más Años , Femenino , Lateralidad Funcional/fisiología , Marcha/fisiología , Humanos , Masculino , Persona de Mediana Edad
13.
Brain Cogn ; 48(2-3): 625-31, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12030519

RESUMEN

The present study examined the similarities between the diurnal time courses in the waking EEG activity and the psychomotor performance. The aim was to verify if some ongoing changes in the excitability of the cortical nerve cells across the daytime could facilitate the sensorimotor processing. EEG recordings and performance results for the Four Choice Reaction Time Test (FCRTT) were obtained every two hours, from morning to late evening period, in 8 young normal subjects (21.3 +/- 0.5 years). ANOVAs were used to verify the presence of diurnal variations in the two measures. Nonparametric correlations were obtained to test the similarity between the changes across the day in the two measures. Three EEG frequency bands (delta, sigma, and beta1) and the reaction time measures varied across the daytime. The changes in the sigma (12.00-13.75 Hz) and the beta1 (14.00-19.75 Hz) bands were similar to the diurnal variations in the reaction time measures. It is suggested that the changes in the sigma and the beta1 bands may facilitate the processing of the sensorimotor treatment.


Asunto(s)
Ritmo Circadiano/fisiología , Electroencefalografía , Desempeño Psicomotor/fisiología , Vigilia/fisiología , Adulto , Electromiografía , Femenino , Humanos , Masculino , Tiempo de Reacción
14.
Br J Pharmacol ; 135(2): 462-8, 2002 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11815382

RESUMEN

In the present study, pharmacological properties of a bradykinin B(2) receptor amplified either from guinea-pig ileum or lung and homologous to the previously reported sequence except two amino-acid changes L(124)-->P and N(227)-->Y in the receptor protein were characterized. Tritiated bradykinin ([(3)H]-BK) specifically bound to the cloned guinea-pig B(2) bradykinin receptor stably expressed in Chinese hamster ovary cells (CHO-K1) with a K(D) value of 0.29+/-0.07 nM. In competition experiments, bradykinin (BK) affinity constant value was 0.21+/-0.05 nM while the two specific kinin B(1) ligands, des-Arg(9)-bradykinin (DBK) and des-Arg(9)-Leu(8)-bradykinin (DLBK) were unable to compete with [(3)H]-BK. As the specific peptide antagonist D-Arg-[Hyp(3),Thi(5),D-Tic(7),Oic(8)]-bradykinin (HOE140), (E)-3-(6-acetamido-3-pyridil)-N-[-N-[2,4-dichloro-3-[(2-methyl-8-quinolinyl)oxymethyl]phenyl]-N-methylaminocarbonylmethyl]acrylamide (FR173657) and 1-[[3-[2,4-dimethylquinolin-8-yl)oxymethyl] - 2,4 - dichloro - phenyl]sulfonyl] - 2(S) - [[4-[4-(aminoiminomethyl)-phenylcarbonyl]piperazin-1-yl]carbonyl]pyrrolidine (LF16-0335C) exhibited a high affinity for this receptor with K(i) values of 7.34+/-2.45 nM and 8.54+/-1.55 nM respectively. BK and kallidin (KD) increased inositol phosphates (IPs) levels with EC(50) values of 0.44+/-0.12 nM and 6.88+/-0.28 nM, respectively. Neither DLBK nor DBK (0.01 nM to 10 microM) stimulated or inhibited IPs turnover and as expected HOE140 did not raise IPs production. HOE140 (0.1 microM) and LF 16-0335c (1 microM) right shifted the BK response curve with pK(B) values of 9.2+/-0.4 and 8.4+/-0.3, respectively. The results indicate that this cloned guinea-pig receptor displayed typical pharmacological properties of a bradykinin B(2) receptor and support the existence of a single B(2) receptor in this species.


Asunto(s)
Células CHO/efectos de los fármacos , Células CHO/metabolismo , Receptores de Bradiquinina/fisiología , Animales , Bradiquinina/farmacología , Bradiquinina/fisiología , Clonación Molecular , Cricetinae , Relación Dosis-Respuesta a Droga , Cobayas , Íleon/efectos de los fármacos , Íleon/metabolismo , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Receptor de Bradiquinina B2 , Receptores de Bradiquinina/genética
15.
J Biol Rhythms ; 16(5): 502-11, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11669423

RESUMEN

Light exposure was measured in 30 permanent night nurses to determine if specific light/dark profiles could be associated with a better circadian adaptation. Circadian adaptation was defined as a significant shift in the timing of the episode of melatonin secretion into the daytime. Light exposure was continuously recorded with ambulatory wrist monitors for 56 h, including 3 consecutive nights of work. Participants were then admitted to the laboratory for 24 h where urine was collected every 2 h under dim light for the determination of 6-sulphatoxymelatonin concentration. Cosinor analysis was used to estimate the phase position of the episode of melatonin secretion. Five participants showed a circadian adaptation by phase delay ("delayed participants") and 3 participants showed a circadian adaptation by phase advance ("advanced participants"). The other 22 participants had a timing of melatonin secretion typical of day-oriented people ("nonshifters"). There was no significant difference between the 3 groups for total light exposure or for bright light exposure in the morning when traveling home. However, the 24-h profiles of light exposure were very distinctive. The timing of the main sleep episode was associated with the timing of light exposure. Delayed participants, however, slept in darker bedrooms, and this had a major impact on their profile of light/dark exposure. Delayed and advanced participants scored as evening and morning types, respectively, on a morningness-eveningness scale. This observation suggests that circadian phase prior to night work may contribute to the initial step toward circadian adaptation, later reinforced by specific patterns of light exposure.


Asunto(s)
Ritmo Circadiano/fisiología , Melatonina/análogos & derivados , Melatonina/metabolismo , Adaptación Fisiológica , Adulto , Femenino , Humanos , Luz , Masculino , Melatonina/orina , Persona de Mediana Edad , Sueño/fisiología
16.
Microbes Infect ; 3(9): 729-38, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11489421

RESUMEN

A number of recent reports have described the isolation and characterization of Brucella strains from a wide variety of marine mammals such as seals, porpoises, dolphins and a minke whale. These strains were identified as brucellae by conventional typing tests. However, their overall characteristics were not assimilable to those of any of the six currently recognized Brucella species and it was suggested that they comprise a new nomen species to be called Brucella maris. In the present study we analysed DNA polymorphism at the omp2 locus of 33 marine mammal Brucella strains isolated from seals, dolphins, porpoises and an otter. The omp2 locus contains two gene copies (named omp2a and omp2b) coding for porin proteins and has been found particularly useful for molecular typing and identification of Brucella at the species, biovar, or strain level. PCR-restriction fragment length polymorphism (RFLP) and DNA sequencing showed that strains isolated from dolphins and porpoises carry two omp2b gene copies instead of one omp2a and one omp2b gene copy or two similar omp2a gene copies reported in the currently recognized species. This observation was also recently made for a minke whale Brucella isolate. The otter and all seal isolates except one were shown to carry one omp2a and one omp2b gene copy as encountered in isolates from terrestrial mammals. By PCR-RFLP of the omp2b gene, a specific marker was detected grouping the marine mammal Brucella isolates. Although marine mammal Brucella isolates may represent a separate group from terrestrial mammal isolates based on omp2b sequence constructed phylogenetic trees, the divergence found between their omp2b and also between their omp2a nucleotide sequences indicates that they form a more heterogeneous group than isolates from terrestrial mammals. Therefore, grouping the marine mammal Brucella isolates into one species Brucella maris seems inappropriate unless the currently recognized Brucella species are grouped. With respect to the current classification of brucellae according to the preferential host, brucellae isolated from such diverse marine mammal species as seals and dolphins could actually comprise more than one species, and at least two new species, B. pinnipediae and B. cetaceae, could be compatible with the classical criteria of host preferentialism and DNA polymorphism at their omp2 locus.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa/genética , Brucella/clasificación , Delfines/microbiología , Nutrias/microbiología , Marsopas/microbiología , Phocidae/microbiología , Animales , Brucella/genética , Brucella/aislamiento & purificación , Brucelosis/microbiología , Brucelosis/veterinaria , ADN Bacteriano/análisis , ADN Bacteriano/genética , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Polimorfismo Genético/genética , Polimorfismo de Longitud del Fragmento de Restricción , Agua de Mar , Análisis de Secuencia de ADN
17.
J Biol Chem ; 276(44): 41100-11, 2001 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-11495910

RESUMEN

A prototypic study of the molecular mechanisms of activation or inactivation of peptide hormone G protein-coupled receptors was carried out on the human B2 bradykinin receptor. A detailed pharmacological analysis of receptor mutants possessing either increased constitutive activity or impaired activation or ligand recognition allowed us to propose key residues participating in intramolecular interaction networks stabilizing receptor inactive or active conformations: Asn(113) and Tyr(115) (TM III), Trp(256) and Phe(259) (TM VI), Tyr(295) (TM VII) which are homologous of the rhodopsin residues Gly(120), Glu(122), Trp(265), Tyr(268), and Lys(296), respectively. An essential experimental finding was the spatial proximity between Asn(113), which is the cornerstone of inactive conformations, and Trp(256) which plays a subtle role in controlling the balance between active and inactive conformations. Molecular modeling and mutagenesis data showed that Trp(256) and Tyr(295) constitute, together with Gln(288), receptor contact points with original nonpeptidic ligands. It provided an explanation for the ligand inverse agonist behavior on the WT receptor, with underlying restricted motions of TMs III, VI, and VII, and its agonist behavior on the Ala(113) and Phe(256) constitutively activated mutants. These data on the B2 receptor emphasize that conformational equilibria are controlled in a coordinated fashion by key residues which are located at strategic positions for several G protein-coupled receptors. They are discussed in comparison with the recently determined rhodopsin crystallographic structure.


Asunto(s)
Receptores de Bradiquinina/química , Rodopsina/química , Secuencia de Aminoácidos , Asparagina/química , Asparagina/metabolismo , Humanos , Ligandos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Conformación Proteica , Receptor de Bradiquinina B2 , Receptores de Bradiquinina/metabolismo , Homología de Secuencia de Aminoácido , Triptófano/química , Triptófano/metabolismo
18.
J Bacteriol ; 183(16): 4839-47, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11466287

RESUMEN

Omp2a and Omp2b are highly homologous porins present in the outer membrane of the bacteria from the genus Brucella, a facultative intracellular pathogen. The genes coding for these proteins are closely linked in the Brucella genome and oriented in opposite directions. In this work, we present the cloning, purification, and characterization of four Omp2b size variants found in various Brucella species, and we compare their antigenic and functional properties to the Omp2a and Omp2b porins of Brucella melitensis reference strain 16M. The variation of the Omp2a and Omp2b porin sequences among the various strains of the genus Brucella seems to result mostly from multiple gene conversions between the two highly homologous genes. As shown in this study, this phenomenon has led to the creation of natural Omp2a and Omp2b chimeric proteins in Omp2b porin size variants. The comparison by liposome swelling assay of the porins sugar permeability suggested a possible functional differences between Omp2a and Omp2b, with Omp2a showing a more efficient pore in sugar diffusion. The sequence variability in the Omp2b size variants was located in the predicted external loops of the porin. Several epitopes recognized by anti-Omp2b monoclonal antibodies were mapped by comparison of the Omp2b size variants antigenicity, and two of them were located in the most exposed surface loops. However, since variations are mostly driven by simple exchanges of conserved motifs between the two genes (except for an Omp2b version from an atypical strain of Brucella suis biovar 3), the porin variability does not result in major antigenic variability of the Brucella surface that could help the bacteria during the reinfection of a host. Porin variation in Brucella seems to result mainly in porin conductivity modifications.


Asunto(s)
Proteínas Bacterianas , Brucella/genética , Variación Genética , Porinas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Brucella melitensis/genética , Mapeo Cromosómico , Dicroismo Circular , Clonación Molecular , Datos de Secuencia Molecular , Plásmidos , Porinas/química , Conformación Proteica , Alineación de Secuencia , Análisis de Secuencia de Proteína , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie
19.
J Dairy Sci ; 83(11): 2393-409, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11104256

RESUMEN

A three-layer feedforward neural network was successfully used to model and predict the pH of cheese curd at various stages during the cheese-making process. An extended database, containing more than 1800 vats over 3 yr of production of Cheddar cheese with eight different starters, from a large cheese plant was used for model development and parameter estimation. Neural network models were developed with inputs selected among 33 quantitative and qualitative process variables for final pH of cheese, pH at cutting, and acidity at whey drawing-off and at pressing. In all cases, very high correlation coefficients, ranging from 0.853 to 0.926, were obtained with the validation data. A sensitivity analysis of neural network models allowed the relative importance of each input process variable to be identified. The sensitivity analysis in conjunction with a priori knowledge permitted a significant reduction in the size of the model input vector. A neural network model using only nine input process variables was able to predict the final pH of cheese with the same accuracy as for the complete model with 33 original input variables. This significant decrease in the size of neural networks is important for applications of process control in cheese manufacturing.


Asunto(s)
Queso , Manipulación de Alimentos/métodos , Redes Neurales de la Computación , Biotecnología/métodos , Concentración de Iones de Hidrógeno
20.
Br J Surg ; 87(10): 1366-74, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11044163

RESUMEN

BACKGROUND: The best way to manage generalized peritonitis complicating sigmoid diverticulitis is controversial. This randomized clinical trial involved a comparison of primary resection and suture, drainage with proximal colostomy followed by secondary resection. METHODS: From January 1989 to December 1996, 105 patients of mean(s.d.) age 66(14) (range 32-91) years were randomized to undergo primary or secondary resection. The main endpoint was occurrence of generalized or localized postoperative peritonitis. The Mannheim Peritonitis Index score was calculated for each patient to check for comparability of groups. RESULTS: Postoperative peritonitis occurred less often after primary than secondary resection whether considering the first procedure only (one of 55 patients versus ten of 48; P < 0.01) or all procedures (one of 55 versus 12 of 48; P < 0.001). Likewise, early reoperation was performed less often following primary resection than secondary resection (two of 55 versus nine of 48 (P < 0.02) and two versus 11 (P < 0.01)), leading to a shorter median first hospital stay for patients having primary resection (15 days) than for those undergoing secondary resection (24 days) (P < 0.05). The mortality rate did not differ significantly with regard to operative policy (primary resection 24 per cent versus secondary resection 19 per cent) or type of peritonitis (faeculent 27 per cent versus purulent 19 per cent). No patient died following a second or third procedure. CONCLUSION: Primary resection is superior to secondary resection in the treatment of generalized peritonitis complicating sigmoid diverticulitis because of significantly less postoperative peritonitis, fewer reoperations and shorter hospital stay.


Asunto(s)
Diverticulitis del Colon/cirugía , Peritonitis/etiología , Complicaciones Posoperatorias/etiología , Enfermedades del Sigmoide/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Diverticulitis del Colon/complicaciones , Humanos , Persona de Mediana Edad , Cuidados Posoperatorios/métodos , Reoperación , Factores de Riesgo , Enfermedades del Sigmoide/complicaciones , Análisis de Supervivencia , Resultado del Tratamiento
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