RESUMEN
The refracture rate after major trauma is approximately half (57%) the refracture rate after a minimal trauma injury. Extending Fracture Liaison Service activity to include major trauma patients creates significant additional direct cost, but remains essentially cost neutral if notional savings through refracture risk reduction are taken into account. PURPOSE: To compare the 3-year refracture rate following minimal trauma (MT) and non-minimal trauma (non-MT) injuries and evaluate the cost of extending fracture liaison service (FLS) operations to non-MT presentations. METHODS: Patients aged 50, or above presenting to the John Hunter Hospital with a fracture in calendar year 2018 were identified through the Integrated Patient Management System (IPMS) of the Hunter New England Health Service's (HNEHS), and re-presentation to any HNEHS facility over the following 3 years monitored. The refracture rate of MT and non-MT presentations was compared and analysed using Cox proportional hazards regression models. The cost of including non-MT patients was estimated through the use of a previously conducted micro-costing analysis. The operational fidelity of the FLS to the previous estimate was confirmed by comparing the 3-year refracture rate of MT presentations in the two studies. RESULTS: The 3-year refracture rate following a MT injury was 8% and after non-MT injury 4.5%. Extension of FLS activities to include non-MT patients in 2022 would have cost an additional $198,326 AUD with a notional loss/saving of $ - 26,625/ + 26,913 AUD through refracture risk reduction. No clinically available characteristic at presentation predictive of increased refracture risk was identified. CONCLUSION: The 3-year refracture after a non-MT injury is about half (57%) that of the refracture rate after a MT injury. Extending FLS activity to non-MT patients incurs a significant additional direct cost but remains cost neutral if notional savings gained through reduction in refracture risk are taken into account.
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Análisis Costo-Beneficio , Fracturas Osteoporóticas , Recurrencia , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Fracturas Osteoporóticas/economía , Fracturas Osteoporóticas/prevención & control , Costos de la Atención en Salud/estadística & datos numéricos , Anciano de 80 o más Años , Prestación Integrada de Atención de Salud/economía , Prestación Integrada de Atención de Salud/organización & administración , New England , Prevención Secundaria/economía , Prevención Secundaria/organización & administraciónRESUMEN
SUMMARY: We assessed the ability of a fracture liaison service (FLS) to directly reduce re-fracture risk. Having a FLS is associated with a â¼40% reduction in the 3-year risk of major bone and â¼30% of any bone re-fracture. The number needed to treat to prevent a re-fracture is 20. INTRODUCTION: FLS have been promoted as the most effective interventions for secondary fracture prevention, and while there is evidence of increased rate of investigation and treatment at institutions with a FLS, only a few studies have considered fracture outcomes directly. We therefore sought to evaluate the ability of our FLS to reduce re-fracture risk. METHODS: Historical cohort study of all patients ≥50 years presenting over a 6-month period with a minimal trauma fracture (MTF) to the emergency departments of a tertiary hospital with a FLS, and one without a FLS. Baseline characteristics, mortality and MTFs over a 3-year follow-up were recorded. RESULTS: Five hundred fifteen patients at the FLS hospital and 416 patients at the non-FLS hospital were studied. Over 3 years, 63/515 (12%) patients at the FLS hospital and 70/416 (17%) at the non-FLS hospital had a MTF. All patients were analysed in an intention-to-treat analysis regardless of whether they were seen in the FLS follow-up clinic. Statistical analysis using Cox proportional hazard models in the presence of a competing risk of death from any cause was used. After adjustment for baseline characteristics, there was a â¼30% reduction in rate of any re-fracture at the FLS hospital (hazard ratio (HR) 0.67, confidence interval (CI) 0.47-0.95, p value 0.025) and a â¼40% reduction in major re-fractures (hip, spine, femur, pelvis or humerus) (HR 0.59, CI 0.39-0.90, p value 0.013). CONCLUSIONS: We found a â¼30% reduction in any re-fractures and a â¼40% reduction in major re-fractures at the FLS hospital compared with a similar non-FLS hospital. The number of patients needed to treat to prevent one new fracture over 3 years is 20.
Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Prestación Integrada de Atención de Salud/organización & administración , Fracturas Osteoporóticas/prevención & control , Anciano , Anciano de 80 o más Años , Medicina Basada en la Evidencia/métodos , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Nueva Gales del Sur/epidemiología , Osteoporosis/tratamiento farmacológico , Osteoporosis/epidemiología , Fracturas Osteoporóticas/epidemiología , Recurrencia , Estudios Retrospectivos , Prevención Secundaria/organización & administraciónRESUMEN
OBJECTIVES: To determine the prevalence and correlates of antiphospholipid antibodies (APLA) in systemic sclerosis (SSc). METHODS: Nine hundred and forty SSc patients were tested for APLA using an ELISA assay at recruitment. Clinical manifestations were defined as present, if ever present from SSc diagnosis. Logistic regression analysis was used to determine the associations of APLA. RESULTS: One or more types of APLA were present in 226 (24.0%) patients. Anticardiolipin (ACA) IgG (ACA-IgG) antibodies were associated with right heart catheter-diagnosed pulmonary arterial hypertension (PAH), with higher titres corresponding with a higher likelihood of PAH (moderate titre (20-39 U/ml) ACA-IgG odds ratio [OR] 1.70, 95% CI: 1.01-2.93, p=0.047; high titre (>40 U/ml) ACA-IgG OR 4.60, 95% CI:1.02-20.8, p=0.047). Both ACA-IgM (OR 2.04, 95% CI: 1.4-3.0, p<0.0001) and ACA-IgG (OR 1.84, 95% CI: 1.2-2.8, p=0.005) were associated with interstitial lung disease (ILD). Increasing ACA-IgM and IgG titres were associated with increased likelihood of ILD. ACA-IgG was a marker of coexistent pulmonary hypertension and ILD (ILD-PH) (OR 2.10, 95% CI: 1.1-4.2, p=0.036). We also found an association between ACA-IgG and digital ulcers (OR 1.76, 95% CI: 1.16-2.67, p=0.008) and ACA-IgM and Raynaud's phenomenon (OR 2.39, 95% CI: 1.08-5.27, p=0.031). There was no association between APLA and SSc disease subtype, peak skin score, presence of other autoantibodies, mortality or other disease manifestations. CONCLUSIONS: The association of APLA with PAH, ILD, ILD-PH, Raynaud's phenomenon and digital ulcers suggests that endothelial abnormalities and small vessel thrombosis may be important in the pathogenesis of these disease features.
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Anticuerpos Anticardiolipina/inmunología , Cardiopatías/inmunología , Hipertensión Pulmonar/inmunología , Enfermedades Pulmonares Intersticiales/inmunología , Esclerodermia Sistémica/inmunología , Anciano , Anticuerpos Antifosfolípidos/inmunología , Estudios de Cohortes , Femenino , Dermatosis de la Mano/etiología , Dermatosis de la Mano/inmunología , Cardiopatías/etiología , Humanos , Hipertensión Pulmonar/etiología , Inmunoglobulina G/inmunología , Inmunoglobulina M/inmunología , Modelos Logísticos , Enfermedades Pulmonares Intersticiales/etiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Enfermedad de Raynaud/etiología , Enfermedad de Raynaud/inmunología , Esclerodermia Sistémica/complicaciones , Úlcera Cutánea/etiología , Úlcera Cutánea/inmunologíaRESUMEN
BACKGROUND: To determine the relationship between gastroesophageal reflux disease (GORD) and its treatment and interstitial lung disease in patients with systemic sclerosis (SSc). METHODS: SSc patients from the Australian Scleroderma Cohort Study (ASCS) were included. GORD was defined as self-reported GORD symptoms, therapy with a proton pump inhibitor (PPI) or histamine 2 receptor antagonist (H2RA) and/or the presence of reflux oesophagitis diagnosed endoscopically. The impact of GORD and its treatment on ILD features (including severity and time to ILD development) and survival was evaluated. RESULTS: GORD was a common manifestation affecting 1539/1632 (94%) of SSc patients. GORD affected 450/469 (96%) of those with SSc-ILD cohort. In SSc-ILD, there was no relationship between the presence of GORD or its treatment and time to ILD development or ILD severity. However, GORD treatment was associated with improved survival in those with ILD (p = 0.002). Combination therapy with both a PPI and a H2RA was associated with a greater survival benefit than single agent therapy with PPI alone (HR 0.3 vs 0.5 p < 0.050 respectively). CONCLUSION: GORD is a common SSc disease manifestation. While the presence or treatment of GORD does not influence the development or severity of ILD, aggressive GORD treatment, in particular with a combination of PPI and H2RA, is associated with improved survival in those with SSc-ILD.
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Reflujo Gastroesofágico , Antagonistas de los Receptores H2 de la Histamina , Enfermedades Pulmonares Intersticiales , Inhibidores de la Bomba de Protones , Esclerodermia Sistémica , Humanos , Reflujo Gastroesofágico/tratamiento farmacológico , Reflujo Gastroesofágico/complicaciones , Enfermedades Pulmonares Intersticiales/tratamiento farmacológico , Femenino , Masculino , Persona de Mediana Edad , Esclerodermia Sistémica/complicaciones , Esclerodermia Sistémica/tratamiento farmacológico , Inhibidores de la Bomba de Protones/uso terapéutico , Anciano , Antagonistas de los Receptores H2 de la Histamina/uso terapéutico , Adulto , Estudios de Cohortes , Resultado del Tratamiento , Australia/epidemiologíaRESUMEN
Neurons encode information and communicate via action potentials, which are generated following the summation of synaptic events. It is commonly assumed that action potentials reset the membrane potential completely, allowing another round of synaptic integration to begin. We show here that the conductances underlying the action potential act instead as a variable reset of synaptic integration. The strength of this reset is cell type-specific and depends on the kinetics, location, and timing of the synaptic input. As a consequence, distal synapses, as well as inputs mediated by N-methyl-d-aspartate receptor activation, can contribute disproportionately to synaptic integration during action potential firing.
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Potenciales de Acción , Potenciales Postsinápticos Excitadores , Células de Purkinje/fisiología , Células Piramidales/fisiología , Transmisión Sináptica , Potenciales de Acción/efectos de los fármacos , Animales , Simulación por Computador , Dendritas/efectos de los fármacos , Dendritas/fisiología , Estimulación Eléctrica , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Cinética , Magnesio/farmacología , Modelos Neurológicos , Neocórtex/citología , Neocórtex/fisiología , Técnicas de Placa-Clamp , Ratas , Receptores AMPA/fisiología , Receptores de N-Metil-D-Aspartato/fisiología , Sinapsis/fisiología , Tetrodotoxina/farmacologíaRESUMEN
BACKGROUND: In functional gastrointestinal disorders a lack of objective biomarkers limits evaluation of underlying mechanisms. We aimed to demonstrate the utility of magnetic resonance imaging for this task using psyllium, an effective constipation treatment, in patients and controls. METHODS: Two crossover studies: (i) adults without constipation (controls, n = 9) took three treatments in randomized order for 6 days - maltodextrin (placebo), psyllium 3.5 g t.d.s and 7 g t.d.s., (ii) adults with chronic constipation (patients, n = 20) took placebo and psyllium 7 g t.d.s. for 6 days. MRI was performed fasting and postprandially on day 6. Measurements included small bowel and ascending colon water content, colonic volume, transit time, and MR relaxometry (T1, T2) to assess colonic chyme. Stool water percentage was measured. RESULTS: 7 g psyllium t.d.s. increased fasting colonic volumes in controls from median 372 mL (IQR 284-601) to 578 mL (IQR 510-882), and in patients from median 831 mL (IQR 745-934) to 1104 mL (847-1316), P < .05. Mean postprandial small bowel water was higher in controls and patients after 7 g psyllium t.d.s. vs placebo. Whole gut transit was slower in patients than controls (P < .05). T1 of the descending colon chyme (fasting) was lower in patients (213 ms, 176-420) than controls (440 ms, 352-884, P < .05) on placebo, but increased by 7 g psyllium t.d.s. (590 ms, 446-1338), P < .001. Descending colon T1 correlated with baseline stool water content and stool frequency on treatment. CONCLUSIONS AND INFERENCES: MRI measurements can objectively demonstrate the mode of action of therapy targeting intestinal fluid content in constipation.
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Catárticos/uso terapéutico , Colon/diagnóstico por imagen , Estreñimiento/diagnóstico por imagen , Tránsito Gastrointestinal/efectos de los fármacos , Psyllium/uso terapéutico , Adulto , Colon/efectos de los fármacos , Colon/fisiopatología , Enfermedades Funcionales del Colon/complicaciones , Enfermedades Funcionales del Colon/diagnóstico por imagen , Enfermedades Funcionales del Colon/tratamiento farmacológico , Estreñimiento/tratamiento farmacológico , Estreñimiento/etiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: We have previously reported a non-invasive, semi-automated technique to assess motility of the wall of the ascending colon (AC) using Magnetic Resonance Imaging. This study investigated the feasibility of using a tagged MRI technique to visualize and assess the degree of flow within the human ascending colon in healthy subjects and those suffering from constipation. METHODS: An open-labeled study of 11 subjects with constipation and 11 subjects without bowel disorders was performed. MRI scans were acquired fasted, then 60 and 120 minutes after ingestion of a 500 mL macrogol preparation. The amount of free fluid in the small and large bowel was assessed using a heavily T2-weighted MRI sequence. The internal movement of the contents of the AC was visualized using a cine tagged MRI sequence and assessed by a novel analysis technique. Comparisons were made between fasting and postprandial scans within individuals, and between the constipation and control groups. KEY RESULTS: Macrogol significantly increased the mobile, MR visible water content of the ascending colon at 60 minutes postingestion compared to fasted data (controls P=.001, constipated group P=.0039). The contents of the AC showed increased motion in healthy subjects but not in the constipated group with significant differences between groups at 60 minutes (P<.002) and 120 minutes (P<.003). CONCLUSIONS AND INFERENCES: This study successfully demonstrated the use of a novel MRI tagging technique to visualize and assess the motion of ascending colon contents following a 500 mL macrogol challenge. Significant differences were demonstrated between healthy and constipated subjects.
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Colon/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Adulto , Femenino , Motilidad Gastrointestinal/fisiología , Humanos , Interpretación de Imagen Asistida por Computador/métodos , MasculinoRESUMEN
BACKGROUND: Recently, cine magnetic resonance imaging (MRI) has shown promise for visualizing movement of the colonic wall, although assessment of data has been subjective and observer dependent. This study aimed to develop an objective and semi-automatic imaging metric of ascending colonic wall movement, using image registration techniques. METHODS: Cine balanced turbo field echo MRI images of ascending colonic motility were acquired over 2 min from 23 healthy volunteers (HVs) at baseline and following two different macrogol stimulus drinks (11 HVs drank 1 L and 12 HVs drank 2 L). Motility metrics derived from large scale geometric and small scale pixel movement parameters following image registration were developed using the post ingestion data and compared to observer grading of wall motion. Inter and intra-observer variability in the highest correlating metric was assessed using Bland-Altman analysis calculated from two separate observations on a subset of data. KEY RESULTS: All the metrics tested showed significant correlation with the observer rating scores. Line analysis (LA) produced the highest correlation coefficient of 0.74 (95% CI: 0.55-0.86), p < 0.001 (Spearman Rho). Bland-Altman analysis of the inter- and intra-observer variability for the LA metric, showed almost zero bias and small limits of agreement between observations (-0.039 to 0.052 intra-observer and -0.051 to 0.054 inter-observer, range of measurement 0-0.353). CONCLUSIONS & INFERENCES: The LA index of colonic motility derived from cine MRI registered data provides a quick, accurate and non-invasive method to detect wall motion within the ascending colon following a colonic stimulus in the form of a macrogol drink.
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Colon/fisiología , Motilidad Gastrointestinal/fisiología , Imagen por Resonancia Cinemagnética/métodos , Adulto , Colon/efectos de los fármacos , Femenino , Motilidad Gastrointestinal/efectos de los fármacos , Humanos , Imagenología Tridimensional/métodos , Masculino , Polietilenglicoles/farmacología , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND/OBJECTIVES: Intake of food or fluid distends the stomach and triggers mechanoreceptors and vagal afferents. Wall stretch and tension produces a feeling of fullness. Duodenal infusion studies assessing gastric sensitivity by barostat have shown that the products of fat digestion have a greater effect on the sensation of fullness and also dyspeptic symptoms than carbohydrates. We tested here the hypothesis that fat and carbohydrate have different effects on gastric sensation under physiological conditions using non-invasive magnetic resonance imaging (MRI) to measure gastric volumes. SUBJECTS/METHODS: Thirteen healthy subjects received a rice pudding test meal with added fat or added carbohydrate on two separate occasions and underwent serial postprandial MRI scans for 4.5 h. Fullness was assessed on a 100-mm visual analogue scale. RESULTS: Gastric half emptying time was significantly slower for the high-carbohydrate meal than for the high-fat meal, P=0.0327. Fullness significantly correlated with gastric volumes for both meals; however, the change from baseline in fullness scores was higher for the high-fat meal for any given change in stomach volume (P=0.0147), despite the lower energy content and faster gastric emptying of the high-fat meal. CONCLUSIONS: Total gastric volume correlates positively and linearly with postprandial fullness and ingestion of a high-fat meal increases this sensation compared with high-carbohydrate meal. These findings can be of clinical interest in patients presenting with postprandial dyspepsia whereby manipulating gastric sensitivity by dietary intervention may help to control digestive sensations.
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Grasas de la Dieta/metabolismo , Digestión/fisiología , Dispepsia/psicología , Vaciamiento Gástrico , Periodo Posprandial/fisiología , Sensación , Estómago , Adulto , Dieta , Dispepsia/fisiopatología , Ingestión de Alimentos , Femenino , Humanos , Masculino , Comidas , Percepción , Saciedad , Estómago/fisiología , Estómago/fisiopatología , Adulto JovenRESUMEN
We have raised antibodies against a synthetic dodecapeptide corresponding to the carboxyl terminus of the predicted met gene product. Phosphorylation of 60 kDa and 65 kDa proteins on tyrosine residues was observed when immunoprecipitates of cells containing the activated human met gene were incubated with [gamma-32P]ATP. Phosphoproteins with the same molecular masses could be immunoprecipitated from cells metabolically labelled with [32P]orthophosphate. When considered together, these observations indicate that the activated human met gene encodes 60 kDa and 65 kDa proteins that can catalyse autophosphorylation on tyrosine residues.
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Genes , Proteínas Tirosina Quinasas/genética , Secuencia de Aminoácidos , Animales , Anticuerpos , Línea Celular , Transformación Celular Neoplásica , Ensayo de Inmunoadsorción Enzimática , Humanos , Metilnitronitrosoguanidina/toxicidad , Ratones , Proteínas Tirosina Quinasas/metabolismoRESUMEN
Features of the dendritic morphology of pyramidal neurones of the visual cortex of the rat that are relevant to the development of models of their passive electrical geometry were investigated. The sample of 39 neurones that was used came from layers 2/3 and 5. They had been recorded from and injected intracellularly with horseradish peroxidase (HRP) in vitro as part of a previous study (Larkman and Mason, J. Neurosci 10:1407, 1990). These cells had been reconstructed and measured previously by light microscopy. The relationship between the diameters of parent and daughter dendrites during branching was examined. It was found that most dendrites did not closely obey the "3/2 branch power relationship" required for representation of the dendrites as single equivalent cylinders. Estimates of total neuronal membrane area ranged from 27,100 +/- 7,900 microns2 for layer 2/3 cells to 52,200 +/- 11,800 microns2 for thick layer 5 cells. Dendritic spines contributed approximately half the total membrane area. Both neuronal input resistance and the ratio of membrane time constant to input resistance were correlated with neuronal membrane area as measured anatomically. The relative electrical lengths of the different dendrites of individual neurones were investigated, by using simple transformations to take account of the differences in diameter and spine density between dendritic segments. A novel "morphotonic" transformation is described that represents the purely morphological component of electrotonic length. Morphotonic lengths can be converted into electrotonic lengths by division by a "morphoelectric factor" ([Rm/Ri]1/2). This procedure has the advantage of separating the steps involving anatomical and electrical parameters. These transformations indicated that the dendrites of the apical terminal arbor were much longer electrically than the basal or apical oblique dendrites. In relative electrical terms, most apical oblique trees arose extremely close to the soma, and terminated at similar distances to the basals. These results indicate that the dendrites of these pyramidal cells cannot be represented as single equivalent cylinders. The electrotonic lengths of the dendrites were calculated by using the electrical parameters specific membrane capacitance (Cm), intracellular resistivity (Ri), and specific membrane resistivity (Rm). Conventional values were assumed for Cm (1.0 muFcm-2) and Ri (100 omega cm), but three different Rm values were used for each cell. Two of these were within the conventionally accepted range (10,000-20,000 omega cm2), while the third value was an order of magnitude higher, in line with some recent evidence from modeling and whole-cell recording studies.(ABSTRACT TRUNCATED AT 400 WORDS)
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Dendritas/ultraestructura , Neuronas/ultraestructura , Tractos Piramidales/citología , Corteza Visual/citología , Animales , Membrana Celular/fisiología , Electrofisiología , Peroxidasa de Rábano Silvestre , Ratas , Ratas Wistar , Médula Espinal/fisiología , Médula Espinal/ultraestructura , Sinapsis/fisiología , Corteza Visual/ultraestructuraRESUMEN
Enzyme-linked immunosorbent assays were used to study (i) binding of rabbit antibodies (raised against litter mate liver plasma membrane fraction) to the immunizing membrane fraction, and (ii) binding of human antibodies to liver membrane fractions and to liver-specific lipoprotein (a liver membrane-derived antigen complex). When assays were conducted using the non-ionic detergent Tween 20 as blocking agent, high non-specific binding was encountered. With the low titre rabbit antisera high binding of non-immune test antibody and of second antibody (anti-rabbit IgG) to the immunogen, and also directly to the solid phase, was found. This was abolished by replacement of Tween 20 in the antibody diluent buffers by a non-reactive protein, casein proving to be a more effective blocking agent than either bovine serum albumin or gelatin. With human sera, high binding of human IgG to the solid phase was noted. This too was blocked by casein, but only when the anti-microbial agent Thimerosal was included in the casein buffer, and when Tween 20 in the wash buffer was replaced by casein-Thimerosal so that the solid phase was exposed to casein before incubation with the test serum. The casein buffers described may prove of general value in solid-phase assays where high non-specific binding is encountered.
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Ensayo de Inmunoadsorción Enzimática/métodos , Proteínas de la Membrana , Especificidad de Anticuerpos , Antígenos de Superficie/inmunología , Tampones (Química) , Membrana Celular/inmunología , Hepatitis/inmunología , Hígado/inmunología , Microsomas/inmunología , Proteínas/inmunologíaRESUMEN
Guinea pig antisera raised against human and rabbit liver-specific membrane lipoprotein (LSP) have been used to develop a rapid, reproducible and sensitive solid-phase, enzyme-linked immunosorbent assay (ELISA). The ELISA was used in a series of cross-inhibition experiments to define and quantitate the antigenic specificities of these antisera. The results confirm previous findings that LSP contains both liver-specific and liver non-specific antigens. In addition, it is shown that both human and rabbit LSP contain liver-specific antigens that are species-specific, as well as others that are species cross-reactive. Binding to human LSP was detected by the ELISA with 11 of 13 anti-LSP-positive (by radioimmunoassay) sera from patients with HBsAg-negative chronic active hepatitis. Similar binding was also found with 10 of 11 sera from patients with systemic lupus erythematosus and with 7 of 14 with rheumatoid arthritis --all of which were negative for anti-LSP by radioimmunoassay. It is suggested that immune complexes in these sera might bind to IgG-Fc receptors in LSP and that caution should be exercised in the interpretation of data from ELISA-based studies of anti-LSP in human sera.
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Anticuerpos/análisis , Antígenos de Superficie/análisis , Lipoproteínas/análisis , Hígado/análisis , Proteínas de la Membrana/análisis , Membrana Celular/análisis , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunoglobulina G , Trasplante de Riñón , Lipoproteínas/inmunología , Proteínas de la Membrana/inmunología , MicroquímicaRESUMEN
Our studies of DNA damage and repair in autoimmune disease, lymphomagenesis, and carcinogenesis, require identification of an immunoassay approach that is capable of ultrasensitive detection in a routine human tissue biopsy of several physicochemically diverse antigens, some of which will be present at very low level. Immuno-polymerase chain reaction (immuno-PCR) is a recently described method for ultrasensitive antigen detection that combines the amplification power of PCR with a method similar to a standard antibody capture, enzyme-linked immunosorbent assay (ELISA). As a test of the universality of immuno-PCR, and as an assessment of the suitability of this method for our studies, we used a single immuno-PCR protocol to assay purified forms of the following physicochemically diverse antigens: oligomeric pyruvate dehydrogenase complex (PDC; Mr 8.5 x 10(6)), the promutagenic DNA base adduct O(6)-methylguanosine (Mr 298) and its monomeric repair enzyme, O(6)-methylguanine-DNA methyltransferase (MGMT; Mr 22,000), and a peptide from the N-terminus of MGMT (Mr 2310). We found that all antigens could be ultrasensitively assayed using the single immuno-PCR protocol. Assay limits observed using antigen-specific (primary) antibodies at 1 microg/ml, were in the approximate range of 10(2)-10(9) molecules, with O(6)-methylguanosine being detected most sensitively. Sensitivity of the antigen assay appeared to positively correlate with primary antibody titres determined by ELISA. Furthermore, we observed a substantial increase in detection sensitivity for all antigens by the use of primary antibodies at the higher level of 10 microg/ml. The latter approach permitted antigen assay within the approximate range of 10(0)-10(7) molecules. The combination of higher titre primary antibodies and their use at higher input level, produced an increase of immuno-PCR assay sensitivity of up to four orders of magnitude greater than those previously reported through the use of this assay to measure other antigens. This represents up to a nine order of magnitude increase in immunoassay sensitivity compared to ELISA. Our findings provide compelling evidence that immuno-PCR is indeed a universal ultrasensitive antigen detection method. Using the indicated assay enhancements. immuno-PCR performed as detailed here can offer greatly increased sensitivity for antigen measurement compared to other methods. Thus, our findings suggest that parallel quantitation of several different antigens in very small samples of human tissue will be readily attainable using immuno-PCR.
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Antígenos/química , Antígenos/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Secuencia de Aminoácidos , Animales , Anticuerpos/sangre , Bovinos , Aductos de ADN/inmunología , Acetiltransferasa de Residuos Dihidrolipoil-Lisina , Ensayo de Inmunoadsorción Enzimática/normas , Epítopos/sangre , Humanos , Datos de Secuencia Molecular , O(6)-Metilguanina-ADN Metiltransferasa/inmunología , Péptidos/inmunología , Reacción en Cadena de la Polimerasa/normas , Complejo Piruvato Deshidrogenasa/inmunología , Complejo Piruvato Deshidrogenasa/normas , Sensibilidad y EspecificidadRESUMEN
Endomorphin (EM)-1 and EM-2 are opioid tetrapeptides, reported within the central nervous system, which have very high specificity and affinity for the mu-opioid receptor. We have used newly developed and well-characterised radioimmunoassays (RIAs) in combination with reversed-phase high-performance liquid chromatography (HPLC) to detect EM-1 and EM-2 immunoreactivity (ir) in rat immune tissues. Endomorphins were detectable in extracts of rat spleen (total EM-1-ir/spleen: 440+/-73 pg, mean+/-SEM, a=group of eight rats; EM-2-ir: 150+/-12 pg) and thymus (EM-1-ir: 152+/-18 pg, mean+/-SEM n=8; EM-2-ir: 156+/-28 pg). EM-2-ir was detectable in extracts of human spleen (338+/-196 pg/g tissue, n=3). Multiple peaks of EM-1-ir and EM-2-ir were observed in rat spleen and thymus extracts, and multiple peaks of EM-2-ir were observed in extracts of human spleen, following reversed-phase HPLC and RIAs. This is the first report of endomorphin immunoreactivity in tissues of the rat and human immune systems.
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Sistema Inmunológico/química , Oligopéptidos/análisis , Adulto , Animales , Cromatografía Líquida de Alta Presión , Reacciones Cruzadas , Femenino , Humanos , Sueros Inmunes/inmunología , Masculino , Persona de Mediana Edad , Radioinmunoensayo/métodos , Ratas , Ratas Wistar , Bazo/química , Timo/química , Extractos de Tejidos/químicaRESUMEN
Three colorimetric methods were compared for their suitability for the analysis of sialic acid in human mixed saliva and bovine submaxillary gland mucin. The thiobarbituric acid method was most precise with human saliva, appeared to be subject to the least interference and is therefore the method of choice for these samples. However, it is not possible to use this method for the analysis of bovine mucins. With these samples the resorcinol method was most suitable, being subject to the least interference and relatively precise. The direct Ehrlich method was least precise overall and gave high values with human whole saliva.
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Colorimetría/métodos , Mucinas/análisis , Saliva/análisis , Proteínas y Péptidos Salivales/análisis , Ácidos Siálicos/análisis , Animales , Bovinos , Fucosa/análisis , Glicoproteínas/análisis , Humanos , Hidrólisis , Resorcinoles , TiobarbitúricosRESUMEN
The general solution for the voltage response to a generic impulse current input in a multicylinder somatic shunt cable model for passive neurones has been developed in [1]. In this paper we consider the application of the multicylinder solution to examples previously considered by other authors for the single cylinder case: long and short current input and synaptic input modeled by an alpha-function and a multi-exponential function. Simple expansions appropriate for small and large times are found and efficient means of obtaining these expansions are clearly demonstrated. The dependence of the small and large time solutions upon the dimensionless parameters appearing in the conservation of current condition at the soma is investigated. Relevant limits of these dimensionless parameters which further simplify the small and large time solutions are related back to equivalent dimensional problems of interest to the practitioner. The well-posedness of the dimensionless inverse problem is investigated and a method proposed for the solution of the dimensional inverse problem for the somatic shunt.
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Modelos Neurológicos , Neuronas/fisiología , Animales , Dendritas/fisiología , Estimulación Eléctrica , Electrofisiología , Humanos , Matemática , Sinapsis/fisiologíaRESUMEN
BACKGROUND AND OBJECTIVES: A behavioral science curriculum in family practice residency education encompasses a wide range of topics. Time limitations reduce the number of topics that can be emphasized. This study presents the opinions of practicing family physicians regarding the prioritization of behavioral science topics for residency education. METHODS: We mailed a questionnaire to 633 practicing family physicians. Respondents provided demographic data and rated 28 behavioral science topics according to priority to be given in residency education. RESULTS: A total of 447 questionnaires were returned, for a response rate of 71%. On a 4-point scale, the average ratings of the 28 topics ranged from 3.79 (depression) to 2.40 (enuresis/encopresis). Female physicians and physicians with a behaviorist in their practice provided significantly higher overall average ratings. CONCLUSIONS: Practicing family physicians identify specific behavioral science topics to be given high priority during residency education. The list of prioritized topics may provide a useful guide to help family medicine educators decide which topics to emphasize in the behavioral science curriculum.
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Ciencias de la Conducta/educación , Curriculum/normas , Internado y Residencia , Médicos de Familia/educación , Colorado , Femenino , Humanos , Internado y Residencia/normas , Masculino , Encuestas y CuestionariosRESUMEN
BACKGROUND: Limited information exists about the application of the biopsychosocial model in medical practice. This study expanded our knowledge about the extent to which psychosocial content is included in medical interviews conducted by resident family physicians. METHODS: Interviews of 180 patients conducted by six second-year family practice residents were audiotaped and transcribed. Physician statements were analyzed and coded as social talk, physician-centered statements, patient-centered statements, and discussion of patient affect, family, health promotion, and patient education. RESULTS: The proportion of interviews in which specific physician interactions occurred were physician-centered statements: 100%, patient-centered statements: 66%, dealing with patient affect: 18%, information about family: 61%, initiation of health promotion: 33%, and initiation of patient education: 46%. Discussions of patient opinion/perception, patient affect, family information, and health promotion occurred most commonly during well-care visits and with female patients. CONCLUSIONS: In this sample of residents, providers extended the interview beyond a purely biomedical focus. However, the psychosocial focus often was brief and applied inconsistently across patients.