RESUMEN
A combination of stomach contents, nitrogen stable-isotope and tissue C:N values are presented to demonstrate feeding activity of Atlantic bluefin tuna Thunnus thynnus on the Gulf of Mexico (GOMEX) spawning grounds. Diets include teleosts, cephalopods, crustaceans and a pelagic tunicate (Pyrosoma atlanticum). Results reveal the need to classify the GOMEX as a T. thynnus feeding ground.
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Dieta , Conducta Alimentaria , Atún/fisiología , Animales , Contenido Digestivo , Golfo de México , Isótopos de Nitrógeno/análisisRESUMEN
BACKGROUND: Age at onset modifies prognosis in multiple sclerosis (MS) and may also exert an effect on the characteristics of disease ignition. Understanding how age influences presentation informs disease management and may allow differentiation of distinct clinical sub-groups. OBJECTIVES: To determine the nature of age-specific presentations of relapsing-remitting MS (RRMS) with respect to onset symptoms, gender ratios and index event outcomes. METHODS: In a prospective, population-based sample of 1424 patients in South-East Wales we examined associations between age at onset, clinical features and outcome of the onset event, making specific comparisons between paediatric, adolescent and late-onset MS. RESULTS: Age at onset varied significantly between sexes (Male 31.2, Female 29.3, p = 0.002), 0.7% had paediatric onset, 2.7% adolescent onset and 2.8% late-onset MS (>50 years). Optic neuritis was common in younger patients and declined after age 30. Lower limb motor, facial sensory, sexual and sphincteric symptoms rose with age independent of sex and disease course. F:M ratios were highest <16 years of age and declined with increasing age, with a male excess in those over 50. Probability of complete recovery from index event declined with age from 87.4% in the youngest group to 68% in the eldest (p = 0.009). CONCLUSIONS: Age at disease onset in RRMS exerts a significant effect on gender ratios and presenting phenotype, and allows identification of specific clinical sub-groups. In addition, ability to recover from initial relapse declines with age, suggesting accumulation of disability in MS is an age-dependent response to relapse.
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Progresión de la Enfermedad , Esclerosis Múltiple Recurrente-Remitente/epidemiología , Adolescente , Adulto , Edad de Inicio , Niño , Femenino , Humanos , Masculino , Fenotipo , Recuperación de la Función , Adulto JovenRESUMEN
BACKGROUND: There is increasing evidence of significant and dynamic systemic activation and upregulation of complement in multiple sclerosis (MS), which may contribute to disease pathogenesis. OBJECTIVE: We aimed to investigate the pathological role of complement in MS and the potential role for complement profiling as a biomarker of MS disease state. METHODS: Key components of the classical, alternative and terminal pathways of complement were measured in plasma and cerebrospinal fluid (CSF) of patients with MS in different clinical phases of disease and in matched controls. RESULTS: Increased plasma levels of C3 (p<0.003), C4 (p<0.001), C4a (p<0.001), C1 inhibitor (p<0.001), and factor H (p<0.001), and reduced levels of C9 (p<0.001) were observed in MS patients compared with controls. Combined profiling of these analytes produced a statistical model with a predictive value of 97% for MS and 73% for clinical relapse when combined with selected demographic data. CSF-plasma correlations suggested that source of synthesis of these components was both systemic and central. CONCLUSION: These data provide further evidence of alterations in both local and systemic expression and activation of complement in MS and suggest that complement profiling may be informative as a biomarker of MS disease, although further work is needed to determine its use in distinguishing MS from its differential.
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Proteínas del Sistema Complemento/análisis , Esclerosis Múltiple/sangre , Esclerosis Múltiple/líquido cefalorraquídeo , Adulto , Biomarcadores/sangre , Biomarcadores/líquido cefalorraquídeo , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/inmunologíaRESUMEN
BACKGROUND AND PURPOSE: Neuromyeltis optica (NMO) is a neuroinflammatory disorder considered rare in Caucasian populations. However, accurate population-based epidemiological data for NMO and NMO spectrum disorder (NMO-SD) from Western populations employing validated diagnostic criteria remain limited. We sought therefore to estimate the prevalence and clinical features of NMO in a north European Caucasian population in South East Wales. METHODS: Patients were identified by a comprehensive, multistage ascertainment strategy employing a regional neuroinflammatory disease register, hospital diagnostic databases personal physician referrals and regional requests for anti-aquaporin-4 antibodies (anti-AQP4). RESULTS: Fourteen Caucasian patients (11 patients with NMO and three with NMO-SD) were identified in a population of 712,572 (19.6/million; 95% CIs: 12.2-29.7). There was an excess of females (female:male 12:2), 11/14 were anti-AQP4 positive and 5/14 had disease onset under the age of 20 years. CONCLUSION: This study suggests that NMO and related spectrum disorders are at least as frequent in Northern European populations as in non-Caucasian populations and that the demographic profile of prevalent patients differs from clinic-based cohorts.
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Neuromielitis Óptica/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos/sangre , Acuaporina 4/inmunología , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neuromielitis Óptica/diagnóstico , Neuromielitis Óptica/inmunología , Neuromielitis Óptica/metabolismo , Prevalencia , Gales/epidemiología , Adulto JovenRESUMEN
BACKGROUND: In March 2020, the United Kingdom Multiple Sclerosis Register (UKMSR) established an electronic case return form, designed collaboratively by MS neurologists, to record data about COVID-19 infections in people with MS (pwMS). OBJECTIVES: Examine how hospital admission and mortality are affected by disability, age and disease modifying treatments (DMTs) in people with Multiple Sclerosis with COVID-19. METHODS: Anonymised data were submitted by clinical teams. Regression models were tested for predictors of hospitalisation and mortality outcomes. Separate analyzes compared the first and second 'waves' of the pandemic. RESULTS: Univariable analysis found hospitalisation and mortality were associated with increasing age, male gender, comorbidities, severe disability, and progressive MS; severe disability showed the highest magnitude of association. Being on a DMT was associated with a small, lower risk. Multivariable analysis found only age and male gender were significant. Post hoc analysis demonstrated that factors were significant for hospitalisation but not mortality. In the second wave, hospitalisation and mortality were lower. Separate models of the first and second wave using age and gender found they had a more important role in the second wave. CONCLUSIONS: Features associated with poor outcome in COVID-19 are similar to other populations and being on a DMT was not found to be associated with adverse outcomes, consistent with smaller studies. Once in hospital, no factors were predictive of mortality. Reassuringly, mortality appears lower in the second wave.
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COVID-19 , Esclerosis Múltiple , Humanos , Masculino , Esclerosis Múltiple/epidemiología , Esclerosis Múltiple/terapia , Pandemias , Medición de Resultados Informados por el Paciente , SARS-CoV-2RESUMEN
Patient-derived historical data are widely employed to make fundamental management decisions in multiple sclerosis, although the validity of the information provided is unclear. The objectives of this study were to determine validity of patient-derived historical data and to describe the utility of a locally relevant, patient-administered questionnaire designed to ascertain current disability and other important disease milestones. A well-described cohort of 99 patients was identified for whom comparable, detailed, prospective longitudinal clinician-derived data were available. Patient-derived data were collected by completion of a standardized questionnaire or telephone interview for comparison. Reliability analysis for current Expanded Disability Status Scale (EDSS) demonstrated an intraclass correlation coefficient of 0.79 between questionnaire and clinician-derived data in 79 patients, with complete agreement in 75.9%. Intraclass correlation coefficient for year of disease onset, diagnosis and onset of secondary progression was 0.86, 0.91 and 0.78, respectively. Time to EDSS >4.0, 6.0 and 8.0 all had an intraclass correlation coefficient of >0.9. Less robust agreement was observed for current disease course (Kappa coefficient 0.71), initial relapse rate (intraclass correlation coefficient 0.37) and clinical features at disease onset (Kappa 0.25). We conclude that self-reported questionnaires can provide reliable current and retrospective data on time-to-disability milestones with high levels of correlation observed for some additional elements, supporting the use of selected components of patient-derived data in clinical practice and for epidemiological studies.
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Evaluación de la Discapacidad , Esclerosis Múltiple Crónica Progresiva/diagnóstico , Esclerosis Múltiple Recurrente-Remitente/diagnóstico , Encuestas y Cuestionarios , Edad de Inicio , Algoritmos , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple Crónica Progresiva/epidemiología , Esclerosis Múltiple Recurrente-Remitente/epidemiología , Oportunidad Relativa , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Índice de Severidad de la Enfermedad , Factores de Tiempo , Gales/epidemiologíaRESUMEN
BACKGROUND: Sero-epidemiological studies have demonstrated the association between multiple sclerosis (MS) and prior Epstein-Barr virus (EBV) infection. It has been hypothesized that intermittent peripheral EBV reactivation may drive continuing central inflammation. Recent investigation has shown significant differences in median serum levels of anti-EBV nuclear antigen-1 (EBNA-1) IgG between disease subgroups and positive correlation with disease activity reflected by number of Gd-enhancing lesions and T2 lesion volume. These important data have led to hopes that anti-EBNA-1 IgG may be useful as an easily accessible and effective biomarker of disease activity. METHODS: We examined the applicability of these findings in routine clinical practice, assessing a well-characterized cohort of 100 subjects (25 primary progressive, 25 stable relapsing remitting, 25 active relapsing remitting seen in acute relapse and 25 controls) for serum anti-EBNA-1 IgG using both the Liaison quantitative chemiluminescent assay and Biotest ELISA. RESULTS: We were unable to show a difference in quantitative analysis of serum anti-EBNA-1 IgG levels between disease subgroups and no correlation with phenotypic characteristics including age at onset (r = -0.17, P = 0.16), disease duration (r = 0.03, P = 0.78), EDSS (r = 0.03, P = 0.78) or MSSS (r = 0.02, P = 0.9). In addition, there was only moderate correlation between the two test methods used (intraclass correlation coefficient 0.67; 0.56-0.78) suggesting potential problems with test interpretation. CONCLUSIONS: We have been unable to determine a clinical value for serum anti-EBNA-1 IgG levels in MS or to confirm reported association with disease course and clinical disease activity.
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Antígenos Nucleares del Virus de Epstein-Barr/inmunología , Inmunoglobulina G/sangre , Esclerosis Múltiple/diagnóstico , Esclerosis Múltiple/inmunología , Adulto , Anciano , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Biomarcadores/metabolismo , Evaluación de la Discapacidad , Progresión de la Enfermedad , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/sangre , Esclerosis Múltiple/clasificaciónRESUMEN
The plant embryonic cuticle is a hydrophobic barrier deposited de novo by the embryo during seed development. At germination, it protects the seedling from water loss and is, thus, critical for survival. Embryonic cuticle formation is controlled by a signaling pathway involving the ABNORMAL LEAF SHAPE1 subtilase and the two GASSHO receptor-like kinases. We show that a sulfated peptide, TWISTED SEED1 (TWS1), acts as a GASSHO ligand. Cuticle surveillance depends on the action of the subtilase, which, unlike the TWS1 precursor and the GASSHO receptors, is not produced in the embryo but in the neighboring endosperm. Subtilase-mediated processing of the embryo-derived TWS1 precursor releases the active peptide, triggering GASSHO-dependent cuticle reinforcement in the embryo. Thus, a bidirectional molecular dialogue between embryo and endosperm safeguards cuticle integrity before germination.
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Endospermo/fisiología , Germinación , Semillas/fisiología , Secuencia de Aminoácidos , Endospermo/citología , Endospermo/metabolismo , Ligandos , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Proteínas Quinasas/química , Proteínas Quinasas/metabolismo , Semillas/citología , Semillas/metabolismo , Serina Endopeptidasas/química , Serina Endopeptidasas/metabolismo , Transducción de Señal , Nicotiana/crecimiento & desarrollo , Nicotiana/metabolismoRESUMEN
Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system with a poorly defined and complex immunopathogenesis. Although initiated by reactive T cells, persistent inflammation is evident throughout the disease course. A contribution from complement has long been suspected, based on the results of pathological and functional studies which have demonstrated complement activation products in MS brain and biological fluids. However, the extent and nature of complement activation and its contribution to disease phenotype and long-term outcome remain unclear. Furthermore, functional polymorphisms in components and regulators of the complement system which cause dysregulation, and are known to contribute to other autoimmune inflammatory disorders, have not been investigated to date in MS in any detail. In this paper we review evidence from pathological, animal model and human functional and genetic studies, implicating activation of complement in MS. We also evaluate the potential of complement components and regulators and their polymorphic variants as biomarkers of disease, and suggest appropriate directions for future research.
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Proteínas del Sistema Complemento/inmunología , Esclerosis Múltiple/inmunología , Animales , Biomarcadores/análisis , Activación de Complemento/inmunología , Proteínas del Sistema Complemento/análisis , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/inmunología , Predisposición Genética a la Enfermedad , Humanos , Esclerosis Múltiple/diagnóstico , Esclerosis Múltiple/genética , Neuromielitis Óptica/inmunologíaRESUMEN
BACKGROUND AND AIMS: Epidemiological studies of multiple sclerosis suggest a trend of increasing disease prevalence in susceptible populations. The reasons for this are unclear and may be the results of methodological differences between studies, incomplete ascertainment or advances in technologies that allow the increased identification of early or mild disease. In addition, direct comparison of cross sectional prevalence estimates performed in different epochs in ethnically and geographically distinct populations may be inappropriate. METHODS: Using detailed phenotypic information and standardised methodology, a geographically defined Welsh population was resurveyed after a significant interval, establishing contemporary prevalence rates and examining demographic and clinical data to determine causes of changing disease frequency. RESULTS: Disease prevalence increased 45% from 101 to 146 per 100,000 population over 20 years. The greatest increase was observed in women between the ages of 45 and 54 years. No significant increase in disease frequency was observed in the male population overall, or within specific age groups. There was no demographic evidence for a pattern of earlier age at onset or diagnosis to explain increased disease frequency or decrease in mean age of the prevalent population. In addition, we failed to identify a pattern of recognition of patients with less severe disability. Although there was a modest 13% increase of 2.2 years in mean disease duration, and eight new previously prevalent patients were identified, the main cause of rising disease frequency was related to a 2.8-fold increase in disease incidence for women over 23 years from 2.65 to 7.30/100,000/year increasing the sex ratio of incident patients from 1.8 to 4.3 (women:men). CONCLUSION: Recent change in disease incidence and prevalence in this population is likely to be the result of environmental factors that have been operative in the past few decades in women alone and infers avoidable risk factors. Modelling of current overall incidence suggests a further increase in prevalence to 260 per 100 000 population within the next 20-40 years. Further studies are needed in order to identify recent changes in sex specific environment and lifestyle that confer susceptibility.
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Esclerosis Múltiple/epidemiología , Adolescente , Adulto , Factores de Edad , Edad de Inicio , Anciano , Niño , Preescolar , Estudios de Cohortes , Recolección de Datos , Bases de Datos Factuales , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Factores Sexuales , Gales/epidemiología , Adulto JovenRESUMEN
The recently described leptodactylid frog Rheobatrachus silus of Queensland, Australia, exhibits a unique form of parental care. The female carries embryos and young in the stomach, propulsively ejecting the juveniles.
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Anuros/fisiología , Animales , Anuros/embriología , Anuros/crecimiento & desarrollo , Conducta Animal , Larva/fisiología , Estómago/anatomía & histología , Estómago/fisiologíaRESUMEN
Size and age estimates at sexual maturity were determined for 162 male and 273 female little skates Leucoraja erinacea collected from the western Gulf of Maine. Maturity ogives suggest that 50% maturity in females occurs at age 9.5 years and 480 mm total length (LT), whereas 50% maturity in males occurs at a slightly younger age of 7.7 years and smaller size of 460 mm LT. Age estimates were made from 389 L. erinacea ranging in size from 93 to 570 mm LT. The index of average per cent error and age-bias plots indicated that the ageing methods were precise and non-biased. Additionally, annual periodicity of band formation was validated with oxytetracycline in eight individuals (three males and five females) ranging in age from 3 to 12 years. In conclusion, results from this study indicate that L. erinacea exhibits characteristics that make other elasmobranch populations highly susceptible to overexploitation.
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Tamaño Corporal/fisiología , Maduración Sexual/fisiología , Rajidae/fisiología , Animales , Océano Atlántico , Femenino , Hormonas Esteroides Gonadales/sangre , Maine , Masculino , Rajidae/sangre , Rajidae/crecimiento & desarrollo , Columna Vertebral/crecimiento & desarrolloRESUMEN
BACKGROUND: In patients with multiple sclerosis (MS), the natural history of the disease is of considerable importance to predict and understand long-term outcome and inform choices made by patients and clinicians. This information should ideally be derived from data that reflects the entire disease course. METHODS: In this study, morbidity data from a prevalent cohort established in 1985 have been re-examined after an interval of 20 years to assess factors that may be important in determining outcome. RESULTS: Of 379 patients who fulfilled criteria for definite or probable MS in the original population-based cohort, 221 (58.3%) had died, 149 (39.3%) were alive and 9 (2.4%) were untraceable. Mean Expanded Disability Status Scale (EDSS) score in 1985 was 5.15 (SD 2.7, range 0-9.5) and 8.01 (SD 2.6, range 0-10) in those alive in 2005. Mean worsening of EDSS scores in surviving patients was +3.02 EDSS points, but 14.0% had worsened by <1 EDSS point over 20 years. 61.4% of patients with EDSS 3.5-5.5 and 82.2% of those with an EDSS of
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Evaluación de la Discapacidad , Esclerosis Múltiple/diagnóstico , Esclerosis Múltiple/epidemiología , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Vigilancia de la Población/métodos , Estudios Prospectivos , Índice de Severidad de la EnfermedadRESUMEN
Small GTPases have diverse roles in animals and yeast, including signal transduction, regulation of secretion, organisation of the cytoskeleton, and control of cell division. Similar GTPases have also been found in bacteria, such as the Escherichia coli GTPase ERA, which is involved in regulating metabolism and cell division [1,2]. Many small GTPases have been cloned from plants but their functional analysis has largely been limited to complementation of mutations in corresponding yeast genes, and antisense experiments which have implicated these proteins in processes such as root nodulation [3,4]. No mutations in plant GTPases have been reported, and thus their true importance in plant growth and development is unknown. Here we report the isolation of a gene from Antirrhinum majus encoding a protein from an entirely novel class of eukaryotic GTPases showing strongest similarity to the prokaryotic protein ERA. We have named this gene ERG (for ERA-related GTPase). The ERG gene is expressed in dividing or metabolically active cells. We generated a deletion allele of ERG by site-selected transposon mutagenesis and have shown that seeds containing embryos and endosperm homozygous for this deletion arrest soon after fertilisation. We conclude that ERG has a crucial role in plant growth and development, possibly by influencing mitochondrial division.
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GTP Fosfohidrolasas/genética , Genes de Plantas , Proteínas de Plantas/genética , Plantas/genética , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Secuencia de Bases , Escherichia coli/enzimología , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Plantas/embriología , Semillas/embriología , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Especificidad de la EspecieRESUMEN
OBJECTIVES: The purpose of the work was to establish the level and source of salivary fluoride, whether it could interact with tooth mineral and whether it was able to effect calcium re-acquisition and remineralisation. METHODS: Fluoride in saliva and in solution was measured by electrode, calcium by complexometric titration and phosphate colourimetrically-to measure salivary fluoride, its uptake by mineral and the effects of such low levels on calcium and phosphate levels in solution in contact with suspensions of mineral hydroxyapatite. RESULTS: Fluoride levels in saliva were low but could interact with hydroxyapatite. Such levels caused apatite crystallite growth and preferential acquisition of calcium by calcium-deficient apatite. CONCLUSIONS: Salivary fluoride contents rose with increasing water fluoride levels. It was acquired by hydroxyapatite mineral. Topical fluoride was stored on oral tissues. Even these low fluoride contents could cause mineral crystallite growth with preferential calcium uptake. On a mineral area basis these effects were caused by quite low fluoride uptakes. These findings do not support reliance upon large fluoride uptakes by tooth enamel as evidence for commensurate caries reductions.
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Cariostáticos/farmacocinética , Caries Dental/metabolismo , Durapatita/metabolismo , Fluoruros/farmacocinética , Saliva/química , Calcio/metabolismo , Cristalización , Esmalte Dental/metabolismo , Humanos , Fosfatos/metabolismo , Remineralización DentalRESUMEN
European green lizards (Lacerta viridis) and spiny-tailed agamids (Agama caudospinosum) were obtained from areas endemic for human leishmaniasis. Serum antibody titres against Leishmania agamae, a reptilian leishmanial species, in normal lizards and lizards injected with Leishmania agamae promastigotes were measured by 5 immunological methods commonly used in the serodiagnosis of the human and mammalian leishmaniasis viz. immobilisation test (IMM), direct agglutination (DA), complement-fixation test (CFT), indirect haemagglutination (IHA) and enzyme-linked immunosorbent assay (ELISA). Correlation coefficients (r) were determined for comparisons between each method and linear regression equations calculated to convert antibody titres by one method to those by another. In each lizard species, the IMM test gave the lowest values while the highest were obtained with ELISA. The highest mean titre obtained by ELISA was between 2 and 10 times that obtained by the other methods for both control and immune sera. The methods of preparing the leishmanial antigen extracts affected the IHA and ELISA titres, while the source of complement was critical in obtaining good CFT values. Correlations ranging from 3% to 77% were found for the control animals but higher values ranging from 65% to 96% were obtained with the immunised lizards. Overall, the best correlation was with IHA and ELISA (r greater than 0.82) and with ELISA values for different antigen preparations compared with each other for both control (r greater than 0.67) and immune (r greater than 0.90) sera. ELISA thus appears the most sensitive method for detection and quantitation of anti-flagellate antibodies in normal lizard serum and for the determination of titres in immune serum. ELISA is the most applicable technique for screening reptiles and other lower vertebrates for anti-parasite immunoglobulins, and for screening potential carriers or reservoirs of infective flagellates in epidemiological studies aimed at disease control, especially in areas where human infections are prevalent.
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Anticuerpos/análisis , Técnicas Inmunológicas , Leishmania/inmunología , Lagartos/inmunología , Pruebas de Aglutinación , Animales , Formación de Anticuerpos , Antígenos de Protozoos/inmunología , Movimiento Celular , Pruebas de Fijación del Complemento , Ensayo de Inmunoadsorción Enzimática , Pruebas de Hemaglutinación , Leishmania/fisiología , ConejosRESUMEN
The International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A 'plain' preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel line the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that. The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.
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Estándares de Referencia , Tromboplastina/normas , Organización Mundial de la Salud , Estabilidad de Medicamentos , Humanos , Tiempo de ProtrombinaRESUMEN
Blood samples from 12 normal subjects and 46 patients on oral anticoagulants were divided so that each was anticoagulated with four concentrations of trisodium citrate solution in the range 0.09-0.15 M, 9 vol blood being added to 1 vol citrate solution in each case. Citrated blood haematocrit and plasma prothrombin time was measured on each subsample; 0.025 M CaCl2-solution was used for recalcification throughout. Three laboratories participated, each using a different prothrombin-time technique.
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Citratos/farmacología , Tiempo de Protrombina , Anticoagulantes , Hematócrito , HumanosRESUMEN
Four different heparin preparations--sodium and calcium salts of the same batch of heparin (mean molecular weight 15,000), low molecular weight sodium heparin (mean m.w. 9,000) and high molecular weight sodium heparin (mean m.w. 22,000) were injected subcutaneously on different days each into 6 healthy young volunteers in a randomized trial. Plasma heparin levels were measured using the anti-Xa assay at 1 hour, 3-4 hours and 6-7 hours after the injection. The highest anti-Xa potentiating effect was obtained after the injection of the low molecular weight sodium heparin (mean 0.381 i.u./ml) at 3-4 hours after the injection. With sodium heparin (m.w. 15,000) the highest values (0.135 i.u./ml) were found at 1 hour. Significantly lower anti-Xa potentiating effect was obtained 1 hour after the injection of calcium heparin and in particular after the injection of high molecular weight heparin (mean values 0.072 i. u./ml and 0.043 i. u./ml respectively). Both these preparations showed an increase from 1 hour after injection to 3-4 hours after injection (mean values 0.082 i. u./ml and 0.057 i. u./ml at 3-4 hours after injection). These results indicate that the salt and the molecular weight of the preparation may strongly influence the degree of anticoagulation achieved after subcutaneous injection.
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Heparina/farmacología , Calcio , Factor X/antagonistas & inhibidores , Heparina/administración & dosificación , Heparina/sangre , Humanos , Inyecciones Subcutáneas , Masculino , Peso Molecular , Potasio , Sodio , Factores de TiempoRESUMEN
Freshwater chlamydomonad algae possess flagella surface isoagglutinins of a glycoprotein nature which are involved in gamete recognition and consequent cell fusion. Alternatively, such molecules may have a receptor role in certain Chlamydomonas species. In some freshwater volvocaines, lectin-like substances act as inducers of sexuality. At the moment it is speculative whether these materials can serve as naturally-occurring antibodies to protect algae from environmental antigens.