RESUMEN
OBJECTIVE: To determine the relationships of red blood cell (RBC) transfusion and enteral feeding to changes in intestinal permeability (IP) measured by the relative intestinal uptake of lactulose (La) and rhamnose (Rh) in preterm infantsâ<33 wk gestation. DESIGN/METHODS: Infants 240-326wk gestation received La/Rh solution enterally on study days 1, 8 and 15.Urinary La/Rh ratio was measured by HPLC. Hematocrit preceding transfusion, total RBC transfusion volume, volume/kg, and feeding status during each study interval (birth-d1; d1-d8, and d8-d15) were determined. RESULTS: Of the seventeen (40.5%) subjects who received≥1 transfusion during the study period, 12 (70.6%) infants wereâ<28 wk gestation and 5 (29.4%) infants were≥28 wk gestation, pâ<â0.0001. Lower pre-transfusion hematocrit was observed in intervals preceding high IP (La/Rhâ>â0.05) than in intervals preceding low IP (La/Rh≤0.05) measurements (33 vs 35.8, pâ=â0.1051). RBC transfusions occurred more frequently in intervals preceding high IP than in intervals preceding low IP (26.8%; vs 8.3%, pâ=â0.0275) with 5-fold higher total RBC volume and volume/kg in intervals preceding any time point with high IP. RBC transfusion during an interval was associated with a three-fold increased risk of high IP (aOR 2.7; 95% C.I 0.564-12.814; pâ=â0.2143). Exclusive breast milk exposure and post-menstrual age reduced the risk for high IP following RBC transfusion. CONCLUSIONS: Both RBC transfusion number and volume was associated with subsequent high IP measurements in preterm infantsâ<33 weeks gestation and potentially may contribute to impairment of the preterm intestinal barrier.
Asunto(s)
Nutrición Enteral/métodos , Transfusión de Eritrocitos , Recien Nacido Prematuro/fisiología , Absorción Intestinal/fisiología , Mucosa Intestinal/fisiología , Lactosa/metabolismo , Ramnosa/metabolismo , Nutrición Enteral/efectos adversos , Femenino , Edad Gestacional , Hematócrito , Humanos , Fórmulas Infantiles , Fenómenos Fisiológicos Nutricionales del Lactante/fisiología , Recién Nacido , Masculino , Leche Humana , Estudios RetrospectivosRESUMEN
BACKGROUND: Despite widespread implementation, limited data exists relating morbidity or adverse outcomes to Car Seat Tolerance Screen (CSTS) result in preterm and low birth weight (LBW) neonates. The objective of this study was to determine longer term post-discharge outcomes of infants who failed a CSTS. METHODS: We performed a case control study evaluating outcomes of infants born over one year who failed vs. passed an initial CSTS, utilizing both retrospective medical record review and parental survey data 2-3 years after discharge. Subjects were matched one case of failed CSTS to two controls who passed CSTS based on sex, gestational age, and BW. We performed bivariate analysis of clinical and demographic risk factors comparing those who passed vs. failed CSTS. RESULTS: We identified 19 subjects who failed and matched to 37 controls. Cases were significantly more likely to be diagnosed with obstructive sleep apnea (p = 0.027), asthma (p = 0.016), and be treated with albuterol (p = 0.008). We did not find differences in frequency of urgent care visits or hospital admissions between the groups. Although more of the cases were noted to have developmental delays, the difference was not statistically significant. CONCLUSION: This is the first study to evaluate longer term post-discharge outcomes of subjects having undergone CSTS. Subjects who failed CSTS had significantly increased incidence of respiratory diagnoses such as OSA and asthma than matched controls by 2-3 years after discharge. Larger studies are necessary to further evaluate these findings, but this does provide data that CSTS may be useful in identifying at risk neonates.
Asunto(s)
Apnea/etiología , Bradicardia/etiología , Sistemas de Retención Infantil , Equipo Infantil , Enfermedades del Prematuro/fisiopatología , Alta del Paciente , Posición Supina/fisiología , Apnea/fisiopatología , Bradicardia/fisiopatología , Estudios de Casos y Controles , Sistemas de Retención Infantil/efectos adversos , Contraindicaciones , Femenino , Estudios de Seguimiento , Edad Gestacional , Humanos , Equipo Infantil/efectos adversos , Recién Nacido de Bajo Peso , Recién Nacido , Recien Nacido Prematuro , Masculino , Evaluación en Enfermería , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Estados UnidosRESUMEN
OBJECTIVE: The excipients benzyl alcohol, propylene glycol and ethanol are present in medications used in the neonatal intensive care unit. Exposure to high levels can have adverse effects in a neonatal population. The objective was to quantify excipient exposure in very low birth weight (VLBW) neonates and identify risk factors associated with greater exposure. STUDY DESIGN: A retrospective record review of VLBW infants admitted over 1 year. Excipient exposures were calculated and multivariable regression analyses identified risk factors for increasing exposure. RESULTS: In total, 98% of subjects were exposed to at least one excipient. A total of 5 to 9% received doses higher than recommended for adults. Necrotizing enterocolitis, seizure, bronchopulmonary dysplasia and longer stay predicted higher excipient exposure. CONCLUSION: The excipients examined are in medications commonly prescribed for VLBW neonates, and cumulative doses may exceed recommended exposures for adults. Although safety profiles have not been established, judicious use of medication containing these excipients is warranted for this population.
Asunto(s)
Alcohol Bencilo/farmacología , Etanol/farmacología , Excipientes/farmacología , Recién Nacido de muy Bajo Peso , Propilenglicol/farmacología , Baltimore , Alcohol Bencilo/efectos adversos , Exposición a Riesgos Ambientales , Etanol/efectos adversos , Excipientes/administración & dosificación , Femenino , Humanos , Recién Nacido , Enfermedades del Prematuro/inducido químicamente , Unidades de Cuidado Intensivo Neonatal , Tiempo de Internación , Modelos Logísticos , Masculino , Análisis Multivariante , Propilenglicol/efectos adversos , Estudios Retrospectivos , Medición de Riesgo , Factores de RiesgoRESUMEN
OBJECTIVE: To determine sensitivity, specificity, predictive value of routine fecal occult blood (FOB) testing on the identification of Bell's Stage II or III necrotizing enterocolitis (NEC) in very low birth weight (VLBW) infants. METHODS: Retrospective medical record review of VLBW infants from 2012- 2013 evaluating FOB results and clinical and demographic risk factors. We determined predictive values of positive FOB testing within 48 hours of definite NEC diagnosis. We performed logistic regression analyses for predictors of NEC and for predictors of having positive FOB during NICU admission. RESULTS: The incidence of NEC in our cohort of 203 infants was 3.9% (nâ=â8). None had positive FOB results within 48 hours of diagnosis, and only 12.5% had any positive FOB within 7 days. Sensitivity of positive FOB for predicting definite NECâ=â0%, specificityâ=â34.4%, and positive predictive valueâ=â0%. A majority of VLBWs (67.0%) hadâ>âone positive FOB result during their NICU course. On logistic regression, intrauterine growth restricted (IUGR) infants had significantly higher odds of both developing NEC and of having positive FOB. Positive FOB was not a significant predictor of NEC. Those with lower birth gestational ages had higher odds of positive FOB. CONCLUSIONS: Positive FOB testing occurred in a majority of VLBW infants, with higher odds in the more preterm and IUGR. However, the sensitivity, specificity, and predictive value of routine FOB testing for identifying NEC were all very poor. Our data demonstrates that this test offers no advantages in the early diagnosis of NEC.
Asunto(s)
Enterocolitis Necrotizante/diagnóstico , Enfermedades del Prematuro/diagnóstico , Peso al Nacer , Enterocolitis Necrotizante/sangre , Enterocolitis Necrotizante/fisiopatología , Femenino , Edad Gestacional , Humanos , Incidencia , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/sangre , Recién Nacido de muy Bajo Peso , Unidades de Cuidado Intensivo Neonatal , Masculino , Sangre Oculta , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Estudios Retrospectivos , Factores de Riesgo , Sensibilidad y Especificidad , Estados UnidosRESUMEN
OBJECTIVE: Bone marrow transplantation with total body irradiation (BMT/TBI) has adverse effects on growth, growth hormone status and adiposity. We investigated the GH-IGF-I axis in relation to adiposity. DESIGN: Cross-sectional case control study. PATIENTS: BMT/TBI survivors (n = 22) and short stature control participants (n = 19), all GH-naïve or off GH treatment >3 months. MEASUREMENTS: Auxology, DEXA scans and GH-IGF-I axis investigation: (i) 12-h overnight GH profiles; (ii) insulin tolerance test (ITT); and (iii) IGF-I generation test. ANALYSIS: auto-deconvolution of GH profile data and comparison of quantitative parameters using ANOVA. RESULTS: Eighty-two percent of BMT/TBI survivors had growth hormone deficiency (GHD) using ITT. GH profile area-under-the-curve (GH-AUC) was reduced in BMT/TBI survivors vs short stature control participants [geometric mean (range) 209 (21-825) vs 428 (64-1400) mcg/l/12 h, respectively, P = 0·007]. GHD was more marked in those who had additional cranial irradiation (CRT) [ITT peak 1·4 (0·2-3·0) vs TBI only 4·1 (1·1-14·8) mcg/l, P = 0·036]. GHD was more marked at the end of growth in BMT/TBI survivors vs short stature control participants (GH-AUC 551 (64-2474) vs 1369 (192-4197) mcg/l/12 h, respectively, P = 0·011) and more prevalent (9/11 vs 1/9, respectively, P = 0·005). GH profile data were consistent with ITT results in 80% of participants. IGF-I generation tests were normal. BMT/TBI survivors still demonstrated lower GH levels after adjustment for adiposity (fat-adjusted mean difference for GH-AUC 90·9 mcg/l/12 h, P = 0·025). CONCLUSIONS: GHD was more prevalent in BMT/TBI survivors than expected for the CRT dose in TBI, worsened with time and persisted into adulthood. GHD could not be explained by adiposity. There was no evidence of GH neurosecretory dysfunction or resistance after BMT/TBI.
Asunto(s)
Adiposidad/fisiología , Trasplante de Médula Ósea , Hormona de Crecimiento Humana/sangre , Irradiación Corporal Total/efectos adversos , Adolescente , Adulto , Estudios de Casos y Controles , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
The infant car seat challenge (ICSC), or period of observation in a car safety seat before discharge to monitor for episodes of apnea, bradycardia and desaturation, is one of the most common tests performed on preterm neonates in the United States. However, the utility of the ICSC to identify infants at risk for adverse cardiopulmonary events in the car seat remains unclear. Minimal evidence exists to guide clinicians in performance of this test including appropriate inclusion criteria and failure criteria. In this article, the origins of the ICSC are discussed as well as potential etiologies of desaturations and bradycardia in the car seat position. Current literature on implementation, inclusion and failure criteria, incidence of failure and data on the meaning of a 'passed' vs 'failed' ICSC are discussed. Emphasis is made on minimizing time in car seats and seated devices given concern over the risk of desaturations.
Asunto(s)
Apnea/etiología , Bradicardia/etiología , Sistemas de Retención Infantil/normas , Postura , Diseño de Equipo , Humanos , Lactante , Recién Nacido , Monitoreo Fisiológico , Factores de Riesgo , Estados UnidosRESUMEN
OBJECTIVE: To evaluate how a single infant car-seat challenge (ICSC) predicts subsequent respiratory physiology in premature infants. STUDY DESIGN: Prospective observational study of infants born at <37 weeks gestational age. Subjects underwent three ICSCs and we evaluated clinical characteristics, pass rate, and predictive value of a single ICSC pass. RESULT: Completed three ICSCs on 60 subjects. Seven failed initial ICSC (11.7%). Those who failed had lower birth weights. Of the 53 that initially passed, 47 passed two subsequent tests (89%). Those who passed an initial test and failed a subsequent test had lower weights at each ICSC. CONCLUSION: Our results indicate that passing an ICSC is highly predictive of passing subsequent ICSCs. Lower weights at birth and at the time of ICSC were associated with increased risk of failure. We recommend including low birth weight as an inclusion criterion for ICSCs.
Asunto(s)
Sistemas de Retención Infantil/efectos adversos , Recien Nacido Prematuro/fisiología , Pruebas de Función Respiratoria , Apnea/etiología , Peso Corporal , Edad Gestacional , Humanos , Lactante , Recién Nacido de Bajo Peso , Estudios Prospectivos , Reproducibilidad de los ResultadosRESUMEN
Genetic vaccines are engineered to produce immunogens de novo in the cells of the host for stimulation of a protective immune response. In some of these systems, antigens engineered for rapid degradation have produced an enhanced cellular immune response by more efficient entry into pathways for processing and presentation of MHC class I peptides. VEE replicon particles (VRP), single cycle vaccine vectors derived from Venezuelan equine encephalitis virus (VEE), are examined here for the effect of an increased rate of immunogen degradation on VRP vaccine efficacy. VRP expressing the matrix capsid (MA/CA) portion of SIV Gag were altered to promote rapid degradation of MA/CA by various linkages to co-translated ubiquitin or by destabilizing mutations and were used to immunize BALB/c mice for quantitation of anti-MA/CA cellular and humoral immune responses. Rapid degradation by the N-end rule correlated with a dampened immune response relative to unmodified MA/CA when the VRP carried a glycoprotein spike from an attenuated strain of VEE. In contrast, statistically equivalent numbers of IFNgamma(+)T-cells resulted when VRP expressing unstable MA/CA were packaged with the wild-type VEE glycoproteins. These results suggest that the cell types targeted in vivo by VRP carrying mutant or wild type glycoprotein spikes are functionally different, and are consistent with previous findings suggesting that wild-type VEE glycoproteins preferentially target professional antigen presenting cells that use peptides generated from the degraded antigen for direct presentation on MHC.
Asunto(s)
Antígenos Virales/metabolismo , Virus de la Encefalitis Equina Venezolana/genética , Glicoproteínas/inmunología , Replicón/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/sangre , Especificidad de Anticuerpos , Antígenos Virales/genética , Antígenos Virales/inmunología , Proteínas de la Cápside/genética , Proteínas de la Cápside/inmunología , Proteínas de la Cápside/metabolismo , Línea Celular , Cricetinae , Virus de la Encefalitis Equina Venezolana/fisiología , Productos del Gen gag/química , Vectores Genéticos , Glicoproteínas/genética , Inmunización , Interferón gamma/biosíntesis , Ratones , Ratones Endogámicos BALB C , Replicón/genética , Linfocitos T/inmunología , Factores de Tiempo , Ubiquitina/genética , Ubiquitina/metabolismo , Proteínas de la Matriz Viral/genética , Proteínas de la Matriz Viral/inmunología , Proteínas de la Matriz Viral/metabolismo , Vacunas Virales/administración & dosificación , Virión/inmunología , Virión/metabolismoRESUMEN
The vaccine strategies available for control of emerging encephalitides range in a continuum from traditional approaches to those utilizing new technologies. In this report, we explore the use of live attenuated vaccines where the attenuating mutations have been selected in a rational way to improve attenuation without sacrificing effectiveness. A strategy for paired lethal and resuscitating mutations is presented that will greatly reduce the possibility of reversion to virulence. Finally, we describe an example of a vaccine vector system that could be rapidly adapted for use against these virus diseases as they emerge.
Asunto(s)
Encefalitis Viral/inmunología , Vacunas Virales/uso terapéutico , Animales , Diseño de Fármacos , Humanos , Mutación Puntual , Vacunación/tendencias , Vacunas Atenuadas , Vacunas Virales/genética , Replicación ViralRESUMEN
The course of Venezuelan equine encephalitis (VEE) disease in immunodeficient and immunologically normal mice was compared to define the role of the immune system in this disease process. Immunocompetent mice infected with VEE exhibited a biphasic illness characterized by an early self-limiting lymphoid phase and a fatal CNS phase. The lymphoid phase of the illness was characterized by extensive viral replication within spleen, thymus, Peyer's patches, and lymph nodes, was accompanied by a high-titered serum viremia, and resolved with the production of VEE-specific IgM class antibody at 72 h postinfection (p.i.). Immunocompetent animals survived an average of 6.8 +/- 1.2 days before succumbing to fulminant encephalitis. In contrast, SCID mice infected with VEE showed a persistent replication of virus throughout all organs tested beginning at 24 h p.i. VEE-infected SCID mice exhibited a severe spongiform encephalopathy with 100% mortality and an average survival time of 8.9 +/- 0.9 days. These studies indicated that the characteristic organ tropism of VEE in the mouse is due in large part to an early anti-viral state, the establishment of which is dependent upon the presence of an intact immune system. Finally, the CNS pathology in a VEE-infected mouse had a significant immunologic component. However, in contrast to other neurovirulent alphaviruses, VEE was directly cytopathic for the cells of the CNS, even in the absence of an immune response.
Asunto(s)
Virus de la Encefalitis Equina Venezolana , Encefalomielitis Equina Venezolana/inmunología , Animales , Anticuerpos Antivirales/sangre , Encéfalo/patología , Encéfalo/virología , Modelos Animales de Enfermedad , Encefalomielitis Equina Venezolana/patología , Encefalomielitis Equina Venezolana/virología , Femenino , Inmunoglobulina M/sangre , Ganglios Linfáticos/virología , Ratones , Ratones Endogámicos BALB C , Ratones SCID , Necrosis , Neuronas/patología , Ganglios Linfáticos Agregados/virología , Bazo/patología , Bazo/virología , Timo/virología , Factores de Tiempo , ViremiaRESUMEN
Venezuelan equine encephalitis virus (VEE) is an important equine and human pathogen of the Americas. In the adult mouse model, cDNA-derived, virulent V3000 inoculated subcutaneously (s.c.) causes high-titer peripheral replication followed by neuroinvasion and lethal encephalitis. A single change (G to A) at nucleotide 3 (nt 3) of the 5' untranslated region (UTR) of the V3000 genome resulted in a virus (V3043) that was avirulent in mice. The mechanism of attenuation by the V3043 mutation was studied in vivo and in vitro. Kinetic studies of virus spread in adult mice following s.c. inoculation showed that V3043 replication was reduced in peripheral organs compared to that of V3000, titers in serum also were lower, and V3043 was cleared more rapidly from the periphery than V3000. Because clearance of V3043 from serum began 1 to 2 days prior to clearance of V3000, we examined the involvement of alpha/beta interferon (IFN-alpha/beta) activity in VEE pathogenesis. In IFN-alpha/betaR(-/-) mice, the course of the wild-type disease was extremely rapid, with all animals dying within 48 h (average survival time of 30 h compared to 7.7 days in the wild-type mice). The mutant V3043 was as virulent as the wild type (100% mortality, average survival time of 30 h). Virus titers in serum, peripheral organs, and the brain were similar in V3000- and V3043-infected IFN-alpha/betaR(-/-) mice at all time points up until the death of the animals. Consistent with the in vivo data, the mutant virus exhibited reduced growth in vitro in several cell types except in cells that lacked a functional IFN-alpha/beta pathway. In cells derived from IFN-alpha/betaR(-/-) mice, the mutant virus showed no growth disadvantage compared to the wild-type virus, suggesting that IFN-alpha/beta plays a major role in the attenuation of V3043 compared to V3000. There were no differences in the induction of IFN-alpha/beta between V3000 and V3043, but the mutant virus was more sensitive than V3000 to the antiviral actions of IFN-alpha/beta in two separate in vitro assays, suggesting that the increased sensitivity to IFN-alpha/beta plays a major role in the in vivo attenuation of V3043.
Asunto(s)
Regiones no Traducidas 5'/genética , Virus de la Encefalitis Equina Venezolana/genética , Virus de la Encefalitis Equina Venezolana/patogenicidad , Interferón-alfa/metabolismo , Interferón beta/metabolismo , Mutación/genética , Animales , Línea Celular , Cricetinae , Virus de la Encefalitis Equina Venezolana/efectos de los fármacos , Virus de la Encefalitis Equina Venezolana/fisiología , Encefalomielitis Equina Venezolana/virología , Femenino , Eliminación de Gen , Interferón-alfa/farmacología , Interferón beta/farmacología , Proteínas de la Membrana , Ratones , Ratones Noqueados , Fenotipo , Receptor de Interferón alfa y beta , Receptores de Interferón/genética , Receptores de Interferón/metabolismo , Transducción de Señal/efectos de los fármacos , Tasa de Supervivencia , Regulación hacia Arriba , Virulencia/genética , Replicación Viral/efectos de los fármacosRESUMEN
This article reviews the Montreal experience of hearing preservation in acoustic neuroma surgery. The medical records since 1995 of 36 patients who underwent acoustic neuroma extirpation with the intent to preserve hearing were examined. Intraoperative monitoring was conducted using auditory brainstem response measurement with electrocochleography via a transtympanic electrode. The role of intraoperative monitoring in guiding surgical technique and its correlation with postoperative hearing outcome are discussed. A review of the literature regarding hearing preservation in acoustic neuroma surgery is included.
Asunto(s)
Trastornos de la Audición/prevención & control , Neuroma Acústico/fisiopatología , Neuroma Acústico/cirugía , Complicaciones Posoperatorias/prevención & control , Adulto , Audiometría de Respuesta Evocada , Electrodos , Potenciales Evocados Auditivos del Tronco Encefálico , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Intraoperatorio , Neuroma Acústico/patología , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Venezuelan equine encephalitis virus replicon particles (VRP) containing the gene expressing hemagglutinin (HA) from the human Hong Kong Influenza A isolate (A/HK/156/97) were evaluated as vaccines in chicken embryos and young chicks. Expressed HA was readily detected in bird-tissue staining with anti-H5 HA antibody and in chicken cells infected with the replicon preparations following immunoprecipitation with monoclonal antibody. Birds challenged with a dose of the lethal parent virus were protected to different extents depending on the age of the bird. In ovo and 1-day-old inoculated animals that received no boost with the VRP were partially protected; birds 2 weeks of age were completely protected with a single dose of VRP.
Asunto(s)
Antígenos Virales/genética , Virus de la Encefalitis Equina Venezolana/genética , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Subtipo H5N1 del Virus de la Influenza A , Virus de la Influenza A/inmunología , Gripe Humana/prevención & control , Replicón/genética , Vacunas Sintéticas/administración & dosificación , Vacunas Virales/administración & dosificación , Factores de Edad , Animales , Anticuerpos Monoclonales , Antígenos Virales/análisis , Antígenos Virales/inmunología , Células Cultivadas , Embrión de Pollo , Pollos , Vectores Genéticos , Glicoproteínas Hemaglutininas del Virus de la Influenza/análisis , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Humanos , Inmunohistoquímica , Gripe Humana/veterinaria , Gripe Humana/virología , Enfermedades de las Aves de Corral/prevención & control , VacunaciónRESUMEN
RNA replicon particles derived from a vaccine strain of Venezuelan equine encephalitis virus (VEE) were used as a vector for expression of the major envelope proteins (G(L) and M) of equine arteritis virus (EAV), both individually and in heterodimer form (G(L)/M). Open reading frame 5 (ORF5) encodes the G(L) protein, which expresses the known neutralizing determinants of EAV (U. B. R. Balasuriya, J. F. Patton, P. V. Rossitto, P. J. Timoney, W. H. McCollum, and N. J. MacLachlan, Virology 232:114-128, 1997). ORF5 and ORF6 (which encodes the M protein) of EAV were cloned into two different VEE replicon vectors that contained either one or two 26S subgenomic mRNA promoters. These replicon RNAs were packaged into VEE replicon particles by VEE capsid protein and glycoproteins supplied in trans in cells that were coelectroporated with replicon and helper RNAs. The immunogenicity of individual replicon particle preparations (pVR21-G(L), pVR21-M, and pVR100-G(L)/M) in BALB/c mice was determined. All mice developed antibodies against the recombinant proteins with which they were immunized, but only the mice inoculated with replicon particles expressing the G(L)/M heterodimer developed antibodies that neutralize EAV. The data further confirmed that authentic posttranslational modification and conformational maturation of the recombinant G(L) protein occur only in the presence of the M protein and that this interaction is necessary for induction of neutralizing antibodies.
Asunto(s)
Anticuerpos Antivirales/sangre , Virus de la Encefalitis Equina Venezolana/genética , Equartevirus/metabolismo , Vectores Genéticos , Replicón , Proteínas del Envoltorio Viral/metabolismo , Animales , Línea Celular , Dimerización , Virus de la Encefalitis Equina Venezolana/inmunología , Equartevirus/genética , Inmunización , Ratones , Ratones Endogámicos BALB C , Pruebas de Neutralización , Recombinación Genética , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/inmunología , Vacunas Virales/administración & dosificación , Vacunas Virales/inmunología , ViriónRESUMEN
The early stages of Venezuelan equine encephalitis virus (VEE) pathogenesis in the mouse model have been examined using a genetic approach. Disease progression of a molecularly cloned single-site mutant was compared with that of the parental virus to determine the step in the VEE pathogenetic sequence at which the mutant was blocked. Assuming that such a block constitutes a genetic screen, isolates from different tissues thought to be distal to the block in the VEE pathogenetic sequence were analyzed to determine the pathogenetic step at which revertants of the mutant were selected. Directed mutation and analysis of reversion in vivo provide two powerful genetic tools for the dissection of the wild-type VEE pathogenetic sequence. Virus from the parental virulent clone, V3000, first replicated in the draining lymph node after subcutaneous inoculation in the left rear footpad. Movement of a cloned avirulent mutant, V3010 (E2 76 Glu to Lys), to the draining lymph node was impaired, replication in the node was delayed, and spread beyond the draining lymph node was sporadic. Serum, contralateral lymph node, spleen, and brain isolates from V3010 inoculated animals were invariably revertant with respect to sequence at E2 76 and/or virulence in mice. Revertants isolated from serum and contralateral lymph node retained the V3010 E2 Lys 76 mutation but also contained a second-site mutation, Glu to Lys at E2 116. Modification of the V3010 clone by addition of the second-site mutation at E2 116 produced a virus that bypassed the V3010 block at the draining lymph node but that did not possess full wild-type capacity for replication in the central nervous system or for induction of mortality. A control construct containing only the E2 116 reverting mutation on the V3000 background was identical to V3000 in terms of early pathogenetic steps and virulence. Therefore, analysis of mutant replication and reversion in vivo suggested (1) that the earliest steps in VEE pathogenesis are transit to the draining lymph node and replication at that site, (2) that the mutation in V3010 impairs transit to the draining lymph node and blocks dissemination to other tissues, and (3) that reversion can overcome the block without restoring full virulence.
Asunto(s)
Virus de la Encefalitis Equina Venezolana/genética , Virus de la Encefalitis Equina Venezolana/patogenicidad , Encefalomielitis Equina Venezolana/virología , Mutación Puntual/genética , Supresión Genética/genética , Animales , Encéfalo/virología , Línea Celular , Clonación Molecular , Progresión de la Enfermedad , Virus de la Encefalitis Equina Venezolana/fisiología , Encefalomielitis Equina Venezolana/mortalidad , Femenino , Ganglios Linfáticos/virología , Ratones , Fenotipo , ARN Viral/genética , ARN Viral/metabolismo , Bazo/virología , Relación Estructura-Actividad , Vacunas Atenuadas/genética , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/fisiología , Vacunas Virales/genética , Viremia , Virulencia/genética , Replicación ViralRESUMEN
Vaccine vectors derived from Venezuelan equine encephalitis virus (VEE) that expressed simian immunodeficiency virus (SIV) immunogens were tested in rhesus macaques as part of the effort to design a safe and effective vaccine for human immunodeficiency virus. Immunization with VEE replicon particles induced both humoral and cellular immune responses. Four of four vaccinated animals were protected against disease for at least 16 months following intravenous challenge with a pathogenic SIV swarm, while two of four controls required euthanasia at 10 and 11 weeks. Vaccination reduced the mean peak viral load 100-fold. The plasma viral load was reduced to below the limit of detection (1,500 genome copies/ml) in one vaccinated animal between 6 and 16 weeks postchallenge and in another from week 6 through the last sampling time (40 weeks postchallenge). The extent of reduction in challenge virus replication was directly correlated with the strength of the immune response induced by the vectors, which suggests that vaccination was effective.
Asunto(s)
Virus de la Encefalitis Equina Venezolana/genética , Replicón/genética , Virus de la Inmunodeficiencia de los Simios/inmunología , Vacunas Sintéticas/administración & dosificación , Animales , Anticuerpos Antivirales/biosíntesis , Citotoxicidad Inmunológica , Genes Virales , Vectores Genéticos , Macaca mulatta , Virus de la Inmunodeficiencia de los Simios/genética , Virus de la Inmunodeficiencia de los Simios/patogenicidad , Vacunas Sintéticas/genéticaRESUMEN
Cholesteatomas occurring behind an intact TM are relatively unusual, and intratympanic keratomas are even less common. This article presents the case of a Baffin Zone Inuit gentleman with an intratympanic cholesteatoma confined to the membranous portion of his TM. Although it is generally accepted that many native populations, including the Inuit, demonstrate an elevated preponderance of aural disease, cholesteatoma formation, particularly within the TM, in an individual from this area of the high Arctic is extremely rare.
Asunto(s)
Colesteatoma del Oído Medio/patología , Membrana Timpánica/patología , Adulto , Colesteatoma del Oído Medio/diagnóstico por imagen , Colesteatoma del Oído Medio/cirugía , Humanos , Masculino , Tomografía Computarizada por Rayos XRESUMEN
A live virus vaccine vector has been constructed from a molecularly cloned attenuated strain of Venezuelan equine encephalitis virus (VEE). High levels of foreign protein expression are regulated by an additional copy of the 26 S viral subgenomic RNA promoter. The position of this additional promoter and foreign gene in the VEE genome was predicted to have a major influence on expression level of the heterologous protein. Two sites in the genome were tested to determine the optimal site for expression of the matrix/capsid (MA/CA) coding region of human immunodeficiency virus (HIV-1). One vector contained the additional promoter and the MA/CA genes immediately downstream of the VEE E1 gene at the 3' end of the genome. In the second vector, the additional promoter was introduced immediately upstream from the authentic 26 S subgenomic promoter. Significantly higher levels of MA/CA were expressed from the downstream vector compared to the upstream vector. However, the stability of expression for both vectors was similar following passage in baby hamster kidney cells (BHK) cells. In BALB/c mice, the two vectors elicited similar levels of cellular immune responses to MA/CA as determined by bulk cytotoxic T-lymphocyte assays and precursor frequency analysis, but the humoral response induced by the downstream vector was significantly stronger. At 11 months post boosting with the downstream vector, serum antibody levels against HIV MA/CA were undiminished, and MA/CA specific CTLp were detectable in all mice tested. These findings suggest that VEE vectors can be optimized to elicit strong, balanced and long-lived immune responses to foreign viral proteins.
Asunto(s)
Vacunas contra el SIDA/genética , Virus de la Encefalitis Equina Venezolana/genética , Virus de la Encefalitis Equina Venezolana/inmunología , Vectores Genéticos/síntesis química , Vectores Genéticos/inmunología , VIH-1/genética , Vacunas de ADN/genética , Vacunas contra el SIDA/inmunología , Animales , Cápside/biosíntesis , Cápside/genética , Cápside/inmunología , Células Cultivadas , Cricetinae , Femenino , Genoma Viral , Anticuerpos Anti-VIH/biosíntesis , Anticuerpos Anti-VIH/sangre , VIH-1/inmunología , Humanos , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos BALB C , Regiones Promotoras Genéticas/inmunología , Células Madre/inmunología , Linfocitos T Citotóxicos/inmunología , Proteínas de la Matriz Viral/biosíntesis , Proteínas de la Matriz Viral/genética , Proteínas de la Matriz Viral/inmunologíaRESUMEN
BACKGROUND: Peritoneal tumor dissemination and implantation is a complication of both open and laparoscopic oncologic surgery. This study evaluates the efficacy of paclitaxel-loaded poly(L-lactic acid) microspheres as prophylaxis against intraabdominal tumor seeding. METHODS: 2 x 10(6) 9L glioblastoma cells were introduced into the abdominal cavity of Wistar rats. Fifteen minutes later, the peritoneal cavity was washed with the experimental solutions, and 2 weeks later the presence of tumor implantation was determined. After defining the optimum dose of paclitaxel PLA microspheres in a dose-ranging study, the microsphere formulation was then compared with conventional paclitaxel in four experimental groups (n = 5) as follows: 100 mg of 30% paclitaxel-loaded microspheres; 100 mg PLA microspheres; paclitaxel 4.1 mg; and controls receiving no intraabdominal therapy. RESULTS: Although carcinomatosis developed in all control animals, none in the paclitaxel-loaded microsphere group had biopsy proven cancer. The conventional paclitaxel group (3) showed significant toxicity; only 1 animal survived and had positive histology. CONCLUSIONS: In this animal model of peritoneal carcinomatosis, the paclitaxel-loaded microsphere formulation was more effective than conventional paclitaxel in preventing tumor seeding.