RESUMEN
PURPOSE: The objective of this study is to evaluate the outcomes of total hip arthroplasty (THA) in patients with radiation-related changes to the bone, and specifically whether there is a difference in outcomes between cemented and uncemented acetabular components. METHODS: A database search was performed to identify available studies reporting adults undergoing THA who have previously had pelvic irradiation. Data were extracted and analysed with respect to the use of cemented versus uncemented acetabular components. Statistical analysis was performed using the Chi-square test for independence. RESULTS: The all-cause revision rate was 24% in the cemented THA group (27/111), compared with 15% of uncemented THAs (22/143) (p = 0.073). Revision for acetabular aseptic loosening occurred in 16% of cases (18/111) in the cemented group and 10% (15/143) in the uncemented group (p = 0.178). Acetabular aseptic loosening was reported in 24% of cemented THAs (27/111) and 14% of uncemented THAs (20/143), which was statistically significant (p = 0.035). Not all of these went on to have revision THA. The Incidence of prosthetic joint infection was similar in both groups. CONCLUSION: Overall outcomes appear to be better for uncemented THAs in post-radiotherapy patients, with a significantly lower rate of aseptic loosening and an appreciable (but not statistically significant) reduction in revision rate. The best outcomes seem to be associated with the use of acetabular reinforcement across both cemented and uncemented groups, but further work is needed to evaluate this.
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Artroplastia de Reemplazo de Cadera/métodos , Articulación de la Cadera/efectos de la radiación , Falla de Prótesis , Reoperación/estadística & datos numéricos , Anciano , Artroplastia de Reemplazo de Cadera/efectos adversos , Prótesis de Cadera/estadística & datos numéricos , Humanos , Incidencia , Pelvis/efectos de la radiación , Complicaciones Posoperatorias , Infecciones Relacionadas con Prótesis/epidemiología , Resultado del TratamientoRESUMEN
Conventional methods of treating ankle fractures in the elderly are associated with high rates of complication. We describe the results of treating these injuries in 48 frail elderly patients with a long calcaneotalotibial nail. The mean age of the group was 82 years (61 to 96) and 41 (85%) were women. All were frail, with multiple medical comorbidities and their mean American Society of Anaesthesiologists score was 3 (3 to 4). None could walk independently before their operation. All the fractures were displaced and unstable; the majority (94%, 45 of 48) were low-energy injuries and 40% (19 of 48) were open. The overall mortality at six months was 35%. Of the surviving patients, 90% returned to their pre-injury level of function. The mean pre- and post-operative Olerud and Molander questionnaire scores were 62 and 57 respectively. Complications included superficial infection (4%, two of 48); deep infection (2%, one of 48); a broken or loose distal locking screw (6%, three of 48); valgus malunion (4%, two of 48); and one below-knee amputation following an unsuccessful vascular operation. There were no cases of nonunion, nail breakage or peri-prosthetic fracture. A calcaneotalotibial nail is an excellent device for treating an unstable fracture of the ankle in the frail elderly patient. It allows the patient to mobilise immediately and minimises the risk of bone or wound problems. A long nail which crosses the isthmus of the tibia avoids the risk of peri-prosthetic fracture associated with shorter devices.
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Fracturas de Tobillo , Traumatismos del Tobillo/cirugía , Clavos Ortopédicos , Fijación Intramedular de Fracturas/métodos , Anciano Frágil , Fracturas Osteoporóticas/cirugía , Anciano , Anciano de 80 o más Años , Traumatismos del Tobillo/diagnóstico por imagen , Traumatismos del Tobillo/mortalidad , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Fijación Intramedular de Fracturas/instrumentación , Fijación Intramedular de Fracturas/mortalidad , Curación de Fractura/fisiología , Evaluación Geriátrica , Humanos , Masculino , Persona de Mediana Edad , Fracturas Osteoporóticas/diagnóstico por imagen , Fracturas Osteoporóticas/mortalidad , Complicaciones Posoperatorias/mortalidad , Complicaciones Posoperatorias/fisiopatología , Complicaciones Posoperatorias/terapia , Radiografía , Estudios Retrospectivos , Medición de Riesgo , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
Local recurrence along the biopsy track is a known complication of percutaneous needle biopsy of malignant musculoskeletal tumours. In order to completely excise the track with the tumour its identification is essential, but this becomes increasingly difficult over time. In an initial prospective study, 22 of 45 patients (48.8%) identified over a three-month period, treated by resection of a musculoskeletal tumour, had an unidentifiable biopsy site at operation, with identification statistically more difficult after 50 days. We therefore introduced the practice of marking the biopsy site with India ink. In all 55 patients undergoing this procedure, the biopsy track was identified pre-operatively (100%); this difference was statistically significant. We recommend this technique as a safe, easy and accurate means of ensuring adequate excision of the biopsy track.
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Biopsia con Aguja/métodos , Neoplasias Óseas/patología , Carbono , Neoplasias de los Músculos/patología , Humanos , Estudios ProspectivosRESUMEN
We describe 22 cases of bizarre parosteal osteochondromatous proliferation, or Nora's lesion. These are surface-based osteocartilaginous lesions typically affecting the hands and feet. All patients were identified from the records of a regional bone tumour unit and were treated between 1985 and 2009. Nine lesions involved the metacarpals, seven the metatarsals, one originated from a sesamoid bone of the foot and five from long bones (radius, ulna, tibia, and femur in two). The mean age of the patients was 31.8 years (6 to 66), with 14 men and eight women. Diagnosis was based on the radiological and histological features. The initial surgical treatment was excision in 21 cases and amputation of a toe in one. The mean follow-up was for 32 months (12 to 162). Recurrence occurred in six patients (27.3%), with a mean time to recurrence of 49 months (10 to 120). Two of the eight patients with complete resection margins developed a recurrence (25.0%), compared with four of 14 with a marginal or incomplete resection (28.6%). Given the potential surgical morbidity inherent in resection, our data suggest that there may be a role for a relatively tissue-conserving approach to the excision of these lesions.
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Neoplasias Óseas/cirugía , Osteocondroma/cirugía , Adolescente , Adulto , Anciano , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/patología , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Osteocondroma/diagnóstico por imagen , Osteocondroma/patología , Radiografía , Recurrencia , Estudios Retrospectivos , Resultado del TratamientoAsunto(s)
Artroplastia de Reemplazo de Cadera/efectos adversos , Artroplastia de Reemplazo de Rodilla/efectos adversos , Guantes Quirúrgicos/microbiología , Cuidados Intraoperatorios/métodos , Infección Hospitalaria/microbiología , Infección Hospitalaria/prevención & control , Medios de Cultivo , Contaminación de Equipos , Bacterias Grampositivas/clasificación , Bacterias Grampositivas/aislamiento & purificación , Humanos , Infección de la Herida Quirúrgica/prevención & control , Factores de TiempoRESUMEN
We report on a 67-year-old lady with multiple sclerosis (MS) who underwent bilateral total knee replacements using a fixed bearing posterior cruciate retaining prosthesis. Having initially achieved a satisfactory result, she developed recurrent dislocations of both knees necessitating bilateral revision surgery. Such complications are not previously described as a sequela of a neurological disease.
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Artroplastia de Reemplazo de Rodilla/efectos adversos , Luxación de la Rodilla/complicaciones , Esclerosis Múltiple/complicaciones , Falla de Prótesis , Anciano , Femenino , Humanos , Luxación de la Rodilla/cirugía , Osteoartritis de la Rodilla/cirugía , ReoperaciónRESUMEN
Diarrhea history questionnaires were administered to 369 U.S. military volunteers before and after deployment to Thailand. Additionally, blood samples obtained from a subset of 221 volunteers 1-3 weeks previously and 3-4 weeks after their deployment were tested by enzyme-linked immunosorbent assay for immunoglobulin A to Campylobacter jejuni. Stool samples from personnel (including volunteers) contracting diarrhea in Thailand were cultured for enteric pathogens. Overall, 35.2% (130 of 369) of questionnaire respondents reported one or more diarrhea episodes during their trip. Volunteers with pretravel anti-C. jejuni reciprocal titers < or = 450 were 1.6 times as likely to have had diarrhea during their stay in Thailand compared with those with pretravel titers > 450 (39.7% versus 25.3%; P = 0.05). The symptomatic seroconversion, or attributable Campylobacter diarrhea attack rate, for the 1-month exercise was 12.7% (28 of 221). The symptomatic seroconversion rate in nonimmune (titer < or = 450) volunteers was 17.1%, whereas that in immune volunteers was only 4.0% (P = 0.002). Campylobacter jejuni or C. coli were recovered from 32.9% (56 of 170) of stool samples cultured and were the most commonly identified enteropathogens. Campylobacter diarrhea was associated with elevated temperatures, fecal red cells, and fecal white blood cells. The results of this study show that Campylobacter continues to represent a significant health threat to Western travelers to Thailand, but many of these travelers have preexisting Campylobacter immunity that protects them from clinically significant Campylobacter enteritis.
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Anticuerpos Antibacterianos/sangre , Infecciones por Campylobacter/prevención & control , Campylobacter jejuni/inmunología , Diarrea/prevención & control , Inmunoglobulina A/sangre , Viaje , Adulto , Diarrea/etiología , Humanos , RiesgoRESUMEN
Studies in preterm animal models have shown that antenatal corticosteroids enhance lung maturation by improving a variety of physiologic variables, including lung volumes. Changes in lung volume of preterm infants treated with a full course of antenatal steroids have not been investigated. We hypothesized that a full course of antenatal steroids would significantly increase functional residual capacity (FRC) in treated vs. untreated preterm infants. The objective of our study was to compare FRC and respiratory mechanics in steroid treated vs. untreated preterm infants. FRC and passive respiratory mechanics were prospectively studied within 36 hr of life in 20 infants (25-34 weeks of gestation) who had received a full course of antenatal steroids and in 20 matched untreated preterm infants. FRC was measured with the nitrogen washout method, and respiratory mechanics with the single-breath occlusion technique. Preterm infants who received steroids (n = 20; mean birth weight = 1,230 g; gestational age = 28.8 weeks) had a significantly higher FRC (29.5 vs. 19.3 mL/kg; P < 0.001) than untreated infants (n = 20; birth weight = 1,202 g; gestational age = 28.5 weeks). Passive respiratory system compliance was also increased in treated vs. untreated infants (P < 0.05). In conclusion, FRC and passive respiratory system compliance were significantly improved in preterm infants (25-34 weeks gestation) treated with a full course of antenatal steroids, compared to matched untreated infants. Although this study was not randomized, it confirms that antenatal steroids have important effects on pulmonary function that may contribute to a decreased risk of respiratory distress syndrome in treated preterm infants.
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Recien Nacido Prematuro , Pulmón/crecimiento & desarrollo , Síndrome de Dificultad Respiratoria del Recién Nacido/tratamiento farmacológico , Mecánica Respiratoria/efectos de los fármacos , Esteroides/farmacología , Femenino , Capacidad Residual Funcional , Humanos , Recién Nacido de Bajo Peso , Recién Nacido , Rendimiento Pulmonar , Masculino , Neonatología , Estudios Prospectivos , Síndrome de Dificultad Respiratoria del Recién Nacido/patología , Mecánica Respiratoria/fisiología , Esteroides/uso terapéutico , Resultado del TratamientoRESUMEN
OBJECTIVE: We sought to compare lung mechanics in infants treated with multiple courses of antenatal corticosteroids with those in matched control infants delivered >7 days from dosing and those of matched untreated infants. STUDY DESIGN: Eighteen infants who received multiple courses of corticosteroids and were delivered within 7 days of dosing were matched with 18 infants who received 1 course of corticosteroids >7 days before delivery (remote) and 18 untreated infants. Respiratory compliance and functional residual capacity were measured within 36 hours. Differences were compared by analysis of variance. RESULTS: Infant demographics were similar. Respiratory compliance was higher in the multiple-course group than in the remote or untreated group (P <.02). Functional residual capacity was higher in the multiple-course group than in the untreated group (P <.05) but similar to that found in the remote group. CONCLUSION: Babies delivered after multiple courses of corticosteroids and within 7 days of dosing demonstrated improved respiratory compliance compared with untreated and remotely treated infants. This suggests that the enzyme system responsible for surfactant production can be repetitively induced despite prior treatment with corticosteroids. The increased functional residual capacity in remotely treated infants may reflect a maturation of lung architecture independent of surfactant production.
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Betametasona/administración & dosificación , Feto/efectos de los fármacos , Glucocorticoides/administración & dosificación , Recién Nacido/fisiología , Pulmón/fisiología , Mecánica Respiratoria , Betametasona/uso terapéutico , Parto Obstétrico , Esquema de Medicación , Capacidad Residual Funcional/efectos de los fármacos , Glucocorticoides/uso terapéutico , Humanos , Rendimiento Pulmonar/efectos de los fármacos , Estudios Prospectivos , Factores de TiempoRESUMEN
PURPOSE: Magnetic resonance imaging (MRI) accurately identifies mesial temporal sclerosis (MTS), but prediction of successful surgical outcome ranges from 62% to 96% in published studies. Prior investigations only used patients who had received anterior temporal lobectomy (ATL), potentially overestimating the predictive value of MRI-identified MTS (MRI-MTS). METHODS: The authors performed an intent-to-treat analysis of 90 consecutive patients assessed for possible ATL, including 13 who did not undergo ATL because of inconclusive intracranial ictal EEG. Four (31%) of these 13 patients had unilateral mesial temporal abnormalities on their MRIs. RESULTS: The positive predictive value of MRI-MTS for seizure cessation decreased from 0.69 to 0.63 after adjustment for these additional false positive results. Four previous studies had revealed a positive predictive value of 0.75 (0.72 after similar adjustment). CONCLUSIONS: The authors conclude that the predictive value of MRI-MTS for outcome from ATL may be overestimated by small retrospective studies of highly selected postoperative patients.
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Encefalopatías/diagnóstico , Epilepsia del Lóbulo Temporal/diagnóstico , Epilepsia del Lóbulo Temporal/cirugía , Imagen por Resonancia Magnética/estadística & datos numéricos , Lóbulo Temporal/patología , Lóbulo Temporal/cirugía , Adolescente , Adulto , Encefalopatías/patología , Niño , Estudios de Cohortes , Electroencefalografía/estadística & datos numéricos , Epilepsia del Lóbulo Temporal/patología , Reacciones Falso Positivas , Femenino , Lateralidad Funcional , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Esclerosis/diagnóstico , Resultado del TratamientoRESUMEN
The cpr5 mutant was identified from a screen for constitutive expression of systemic acquired resistance (SAR). This single recessive mutation also leads to spontaneous expression of chlorotic lesions and reduced trichome development. The cpr5 plants were found to be constitutively resistant to two virulent pathogens, Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2; to have endogenous expression of the pathogenesis-related gene 1 (PR-1); and to have an elevated level of salicylic acid (SA). Lines homozygous for cpr5 and either the SA-degrading bacterial gene nahG or the SA-insensitive mutation npr1 do not express PR-1 or exhibit resistance to P. s. maculicola ES4326. Therefore, we conclude that cpr5 acts upstream of SA in inducing SAR. However, the cpr5 npr1 plants retained heightened resistance to P. parasitica Noco2 and elevated expression of the defensin gene PDF1.2, implying that NPR1-independent resistance signaling also occurs. We conclude that the cpr5 mutation leads to constitutive expression of both an NPR1-dependent and an NPR1-independent SAR pathway. Identification of this mutation indicates that these pathways are connected in early signal transduction steps and that they have overlapping functions in providing resistance.
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Proteínas de Arabidopsis , Arabidopsis/genética , Mutación , Proteínas de Plantas/genética , Arabidopsis/microbiología , Hongos/patogenicidad , Genes Recesivos , Pseudomonas/patogenicidadRESUMEN
Fluorescence microscopy was used to study meiosis in microsporocytes from wild-type Arabidopsis thaliana and a T-DNA-tagged meiotic mutant. Techniques for visualizing chromosomes and beta-tubulin in other plant species were evaluated and modified in order to develop a method for analyzing meiosis in A. thaliana anthers. Like most dicots, A. thaliana microsporocytes undergo simultaneous cytokinesis in which both meiotic divisions are completed prior to cytokinesis. However, two unique events were observed in wild-type A. thaliana that have not been reported in other angiosperms: (1) polarization of the microsporocyte cytoskeleton during prophase I prior to nuclear envelope breakdown, and (2) extensive depolymerization of microtubules just prior to metaphase II. The first observation could have implications regarding a previously uncharacterized mechanism for determining the axis of the metaphase I spindle during microsporogenesis. The second observation is peculiar since microtubules are known to be involved in chromosome alignment in other species; possible explanations will be discussed. A T-DNA-tagged meiotic mutant of A. thaliana (syn1), which had previously been shown to produce abnormal microspores with variable DNA content, was also cytologically characterized. The first observable defect occurs in microsporocytes at telophase I, where some chromosomes are scattered throughout the cytoplasm, usually attached to stray microtubules. Subsequent development stages are affected, leading to complete male sterility. Based on similarities to synaptic mutants that have been described in other species, it is suggested that this mutant is defective in synaptonemal complex formation and/or cohesion between sister chromatids.
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Arabidopsis/genética , ADN Bacteriano/genética , ADN de Plantas/genética , Meiosis/genética , Microscopía Fluorescente , Mutación , Fenotipo , Reproducción/genéticaRESUMEN
Extremely low birth weight infants with chronic lung disease (CLD) have frequent episodes of desaturation (hypoxemia). We quantified oxygenation and episodes of hypoxemia in 55 infants (birth weight < or = 1000 gm) with CLD in the supine versus prone position, for 1-hour time intervals. Oxygen saturation was measured with the Nellcor N-200 pulse oximeter and a computer program. Prone positioning increased oxygen saturation from 92.0% to 94.1% (p < 0.001) and significantly decreased episodes of hypoxemia to oxygen saturation levels of less than 90%, 85%, and 80% (p < 0.001). Our findings support prone positioning for the extremely low birth weight infant with CLD in an intensive care setting.
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Hipoxia/prevención & control , Recién Nacido de muy Bajo Peso/sangre , Enfermedades Pulmonares/complicaciones , Enfermedad Crónica , Estudios Cruzados , Humanos , Hipoxia/sangre , Hipoxia/etiología , Recién Nacido , Enfermedades Pulmonares/sangre , Monitoreo Fisiológico , Oximetría/estadística & datos numéricos , Oxígeno/sangre , Posición Prona , Estudios Prospectivos , Estadísticas no Paramétricas , Posición SupinaRESUMEN
PURPOSE: Magnetic resonance imaging, interictal scalp EEG, and ictal scalp EEG each have been shown to localize the primary epileptic region in most patients with mesial-basal temporal lobe epilepsy (MBTLE), but the association of surgical outcome and pathology with each combination of these test results is not known. METHODS: We reviewed the MRI, interictal scalp EEG, and ictal scalp EEG results of 90 consecutive patients with MBTLE. Twelve patients were excluded from the analysis because inconclusive bitemporal intracranial EEG results precluded anterior temporal lobectomy (ATL); none had concordant MRI and interictal scalp EEG results. We compared all combinations of presurgical MRI, interictal EEG, and ictal EEG results to seizure outcome and tissue pathology in the 78 patients who underwent an ATL. RESULTS: Forty-eight (61%) patients had concordant lateralized MRI and interictal EEG temporal lobe abnormalities, with no discordant ictal EEG results; 77% of these patients were seizure-free after ATL. Concordance of MRI and interictal EEG abnormalities correlated with seizure cessation (p < 0.05), compared to all combinations with discordant or nonlateralizing MRI and interictal EEG results. Mesial temporal sclerosis (MTS) was confirmed pathologically in about 80% of both groups (p = 0.5). Outcome in patients with concordant MRI and ictal EEG with nonlateralizing interictal EEG was significantly worse than combinations with concordant MRI and interictal EEG (p < 0.02). CONCLUSIONS: Compared to other combinations of test results, concordance of MRI and interictal EEG is most closely associated with surgical outcome in MBTLE. However, most selected patients have pathologic confirmation of MTS regardless of test results or outcome. This information may be useful for planning the presurgical evaluation of patients with medically intractable MBTLE.
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Electroencefalografía , Epilepsia del Lóbulo Temporal/diagnóstico , Epilepsia del Lóbulo Temporal/cirugía , Imagen por Resonancia Magnética , Lóbulo Temporal/patología , Lóbulo Temporal/cirugía , Adolescente , Adulto , Encefalopatías/patología , Niño , Estudios de Cohortes , Electrodos Implantados , Epilepsia del Lóbulo Temporal/fisiopatología , Femenino , Lateralidad Funcional/fisiología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Esclerosis/patología , Lóbulo Temporal/fisiopatología , Resultado del TratamientoRESUMEN
Rats were raised from weanling until young adulthood in either an enriched condition (EC) or isolated condition (IC). Following this, the locomotor and rewarding effects of amphetamine were determined using the conditioned place preference (CPP) paradigm. EC rats were more sensitive to the acute locomotor stimulant effect and rewarding effect of amphetamine relative to IC rats. In contrast, EC rats were less sensitive than IC rats to the locomotor sensitization effect obtained across repeated amphetamine injections. To determine the effect of environmental enrichment on alteration of brain dopamine (DA) function induced by amphetamine, the effect of amphetamine on electrically evoked release of DA and dihydroxyphenylacetic acid (DOPAC) was determined in vitro using tissue slices from the nucleus accumbens and striatum of EC and IC rats. No differences between EC and IC rats in release of DA or DOPAC were evident, suggesting that the environmentally induced difference in sensitivity to the behavioral effects of amphetamine involves a neural mechanism extrinsic to the mesolimbic and nigrostriatal terminal field regions.
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Anfetamina/farmacología , Dopamina/metabolismo , Ambiente , Actividad Motora/efectos de los fármacos , Ácido 3,4-Dihidroxifenilacético/metabolismo , Animales , Condicionamiento Operante/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Masculino , Neostriado/efectos de los fármacos , Neostriado/metabolismo , Núcleo Accumbens/efectos de los fármacos , Núcleo Accumbens/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Systemic acquired resistance (SAR) is a nonspecific defense response in plants that is associated with an increase in the endogenous level of salicylic acid (SA) and elevated expression of pathogenesis-related (PR) genes. To identify mutants involved in the regulation of PR genes and the onset of SAR, we transformed Arabidopsis with a reporter gene containing the promoter of a beta-1,3-glucanase-encoding PR gene (BGL2) and the coding region of beta-glucuronidase (GUS). The resulting transgenic line (BGL2-GUS) was mutagenized, and the M2 progeny were scored for constitutive GUS activity. We report the characterization of one mutant, cpr1 (constitutive expressor of PR genes), that was identified in this screen and shown by RNA gel blot analysis also to have elevated expression of the endogenous PR genes BGL2, PR-1, and PR-5. Genetic analyses indicated that the phenotype conferred by cpr1 is caused by a single, recessive nuclear mutation and is suppressed in plants producing a bacterial salicylate hydroxylase, which inactivates SA. Furthermore, biochemical analysis showed that the endogenous level of SA is elevated in the mutant. Finally, the cpr1 plants were found to be resistant to the fungal pathogen Peronospora parasitica NOCO2 and the bacterial pathogen Pseudomonas syringae pv maculicola ES4326, which are virulent in wild-type BGL2-GUS plants. Because the cpr1 mutation is recessive and associated with an elevated endogenous level of SA, we propose that the CPR1 gene product acts upstream of SA as a negative regulator of SAR.
Asunto(s)
Arabidopsis/genética , Mutación , Arabidopsis/enzimología , Arabidopsis/inmunología , Arabidopsis/microbiología , Secuencia de Bases , Genes Recesivos , Genes Reporteros , Oxigenasas de Función Mixta/metabolismo , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos , Oomicetos/fisiología , Fenotipo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Pseudomonas/fisiologíaRESUMEN
Systemic acquired resistance (SAR) is a general defense response in plants that is characterized by the expression of pathogenesis-related (PR) genes. SAR can be induced after a hypersensitive response to an avirulent pathogen or by treatment with either salicylic acid (SA) or 2,6-dichloroisonicotinic acid (INA). To dissect the signal transduction pathway of SAR, we isolated an Arabidopsis mutant that lacks the expression of an SA-, INA-, and pathogen-responsive chimeric reporter gene composed of the 5[prime] untranslated region of an Arabidopsis PR gene, [beta]-1,3-glucanase (BGL2), and the coding region of [beta]-glucuronidase (GUS). This mutant, npr1 (nonexpresser of PR genes), carries a single recessive mutation that abolishes the SAR-responsive expression of other PR genes as well. While SA-, INA-, or avirulent pathogen-induced SAR protects wild-type plants from Pseudomonas syringae infection, the mutant cannot be protected by pretreatment with these inducers. The insensitivity of npr1 to SA, INA, and avirulent pathogens in SAR induction indicates that these inducers share a common signal transduction pathway. Moreover, in npr1, the localized expression of PR genes induced by a virulent Pseudomonas pathogen is disrupted, and the lesion formed is less confined. These results suggest a role for PR genes in preventing the proximal spread of pathogens in addition to their suggested role in SAR.
RESUMEN
This study examined the influence of environmental enrichment on the behavioral response to amphetamine. Beginning at 21 days of age, rats were raised in one of three different environmental conditions: a) an enriched condition (EC), in which animals were caged in groups and provided with novel objects daily; b) a social condition (SC), in which animals were caged in groups without any novel objects; and c) an isolated condition (IC), in which animals were caged individually without any novel objects. At 53 days of age, animals from each environmental condition were assessed for amphetamine-induced changes in locomotor activity and reward using the conditioned place preference (CPP) paradigm. Results from saline-injected control animals indicated that EC animals exhibited less vertical activity than IC animals when exposed to the CPP apparatus. When challenged with amphetamine (0.5 or 2.0 mg/kg), there were no significant differences between SC and IC animals in either locomotor behavior or CPP. However, EC animals exhibited more horizontal and vertical activity following amphetamine than both the SC and IC animals. Similarly, EC animals exhibited a greater magnitude of amphetamine-induced CPP than both the SC and IC animals.
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Anfetamina/farmacología , Condicionamiento Operante/efectos de los fármacos , Ambiente , Actividad Motora/efectos de los fármacos , Recompensa , Aislamiento Social , Animales , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
In two separate experiments, rats were raised in either an enriched condition (EC) or impoverished condition (IC) from 21 to 60 days of age. Experiment 1 assessed amphetamine-stimulated locomotor activity and in vivo dopamine (DA) synthesis and metabolism in the nucleus accumbens (NA) and striatum (Str). In Experiment 2, amphetamine-stimulated DA release in the NA and Str was assessed in vitro. The results showed that EC rats have lower basal levels of locomotor activity than IC rats. However, in the presence of amphetamine, EC rats showed a greater increase in locomotion over IC when compared to their own controls. Concomitant with this behavioral difference, EC rats also showed an enhanced neurochemical response to amphetamine in vivo. That is, relative to IC rats, amphetamine produced a greater synthesis of DA in the Str of EC rats, as well as a greater metabolism of DA in the NA of EC rats. In the in vitro DA release experiment, EC rats had a lower concentration of tissue DA than IC. However, in contrast to the in vivo experiment, there were no significant differences between EC and IC rats in amphetamine-stimulated release of DA in vitro in either the Str or NA. The failure of amphetamine to produce differential neurochemical effects in EC and IC rats in vitro may be because this experiment eliminated either pharmacokinetic effects or neurochemical differences in brain regions outside the NA and Str.