RESUMEN
Living organisms are adept in forming inorganic materials (biominerals) with unique structures and properties that exceed the capabilities of engineered materials. Biomimetic materials syntheses are being developed that aim at replicating the advantageous properties of biominerals in vitro and endow them with additional functionalities. Recently, proof-of-concept was provided for an alternative approach that allows for the production of biomineral-based functional materials in vivo. In this approach, the cellular machinery for the biosynthesis of nano-/micropatterned SiO2 (silica) structures in diatoms was genetically engineered to incorporate a monomeric, cofactor-independent ("simple") enzyme, HabB, into diatom silica. In the present work, it is demonstrated that this approach is also applicable for enzymes with "complex" activity requirements, including oligomerization, metal ions, organic redox cofactors, and posttranslational modifications. Functional expression of the enzymes ß-glucuronidase, glucose oxidase, galactose oxidase, and horseradish peroxidase in the diatom Thalassiosira pseudonana was accomplished, and 66 to 78% of the expressed enzymes were stably incorporated into the biosilica. The in vivo incorporated enzymes represent approximately 0.1% (wt/wt) of the diatom biosilica and are stabilized against denaturation and proteolytic degradation. Furthermore, it is demonstrated that the gene construct for in vivo immobilization of glucose oxidase can be utilized as the first negative selection marker for diatom genetic engineering.
Asunto(s)
Diatomeas/enzimología , Enzimas Inmovilizadas/metabolismo , Ingeniería Metabólica/métodos , Dióxido de Silicio/metabolismo , Diatomeas/genética , Galactosa Oxidasa/metabolismo , Glucosa Oxidasa/metabolismo , Glucuronidasa/metabolismo , Peroxidasa de Rábano Silvestre/metabolismo , Reacción en Cadena de la Polimerasa , Dióxido de Silicio/químicaRESUMEN
Employment rights legislative mandates passed in the USA over the last three decades emphasize the importance of validating performance standards for physically strenuous occupations. This study validated minimally acceptable standards for the muscular strength and endurance necessary to perform fire suppression activities. Incumbent firefighters (n=153) selected for key demographic characteristics completed a simulated set of firefighting tasks (Fire Suppression Evolution) and then a Predictor Test Battery of physical abilities tests. Regression analysis revealed that three predictor test items (hose drag/high rise pack carry; arm lift; arm endurance) combined to significantly predict performance time of the Fire Suppression Evolution (p < or =0.01). Firefighters (n=41) rating videotaped performance times of the Fire Suppression Evolution determined that more than one-half a standard deviation slower than the mean time established by the incumbents reflected unacceptable performance. Approximately 80% of incumbent firefighters passed the minimally acceptable performance standard. Use of the 3-predictor test battery would correctly identify 89% of successful performers and 72% of unsuccessful performers. This study demonstrates that validation of minimal physical performance standards will identify a cohort of individuals with a high probability of not being able to perform critical fire suppression activities. This finding has important implications for examining the relationship between physical performance standards and medical and economic outcomes.
Asunto(s)
Selección de Personal/normas , Aptitud Física , Análisis y Desempeño de Tareas , Adulto , Análisis de Varianza , Femenino , Incendios , Humanos , Elevación , Masculino , Persona de Mediana Edad , Resistencia Física , Reproducibilidad de los Resultados , Estados UnidosRESUMEN
This paper examines the association between race and type of service placement for youth with serious emotional and behavioral disturbances. Placements were reviewed for 2,803 black and white youth served in the community mental health system. Differences were found between black and white youth in the type of out-of-home placements they received after controlling for sociodemographic variables and presenting problems. Black youth were more likely than whites to be placed in correctional facilities and foster care while white youth were more likely than blacks to be hospitalized (p < .001). This variation in placement may not be clinically warranted. Placement criteria and outcome assessments are needed.
Asunto(s)
Negro o Afroamericano/psicología , Trastornos de la Conducta Infantil/epidemiología , Servicios Comunitarios de Salud Mental/estadística & datos numéricos , Cuidados en el Hogar de Adopción/estadística & datos numéricos , Hospitalización/estadística & datos numéricos , Institucionalización/estadística & datos numéricos , Prisiones/estadística & datos numéricos , Población Blanca/psicología , Adolescente , Negro o Afroamericano/estadística & datos numéricos , Niño , Trastornos de la Conducta Infantil/clasificación , Trastornos de la Conducta Infantil/terapia , Femenino , Accesibilidad a los Servicios de Salud , Humanos , Delincuencia Juvenil/estadística & datos numéricos , Masculino , Evaluación de Resultado en la Atención de Salud , Muestreo , Virginia/epidemiología , Población Blanca/estadística & datos numéricosRESUMEN
BACKGROUND: Secretin is a peptide hormone that stimulates pancreatic secretion. After recent publicity about a child with autism whose condition markedly improved after a single dose of secretin, thousands of children with autistic disorders may have received secretin injections. METHODS: We conducted a double-blind, placebo-controlled trial of a single intravenous dose of synthetic human secretin in 60 children (age, 3 to 14 years) with autism or pervasive developmental disorder. The children were randomly assigned to treatment with an intravenous infusion of synthetic human secretin (0.4 microg per kilogram of body weight) or saline placebo. We used standardized behavioral measures of the primary and secondary features of autism, including the Autism Behavior Checklist, to assess the degree of impairment at base line and over the course of a four-week period after treatment. RESULTS: Of the 60 children, 4 could not be evaluated - 2 received secretin outside the study, and 2 did not return for follow-up. Thus, 56 children (28 in each group) completed the study. As compared with placebo, secretin treatment was not associated with significant improvements in any of the outcome measures. Among the children in the secretin group, the mean total score on the Autism Behavior Checklist at base line was 59.0 (range of possible values, 0 to 158, with a larger value corresponding to greater impairment), and among those in the placebo group it was 63.2. The mean decreases in scores over the four-week period were 8.9 in the secretin group and 17.8 in the placebo group (mean difference, -8.9; 95 percent confidence interval, -19.4 to 1.6; P=0.11). None of the children had treatment-limiting adverse effects. After they were told the results, 69 percent of the parents of the children in this study said they remained interested in secretin as a treatment for their children. CONCLUSIONS: A single dose of synthetic human secretin is not an effective treatment for autism or pervasive developmental disorder.
Asunto(s)
Trastorno Autístico/tratamiento farmacológico , Secretina/administración & dosificación , Adolescente , Niño , Trastornos Generalizados del Desarrollo Infantil/tratamiento farmacológico , Preescolar , Método Doble Ciego , Humanos , Insuficiencia del TratamientoRESUMEN
Despite literature documenting ureteral obstruction associated with certain gynecological conditions, the occurrence of diuresis among posthysterectomy patients has not been examined. This nonexperimental exploratory study investigated whether diuresis was greater following hysterectomy for conditions that could potentially cause obstruction of the urinary tract than for other conditions requiring hysterectomy. Roy's adaptation model was used to emphasize the importance of expedient detection and intervention of the resultant fluid volume deficit. A retrospective chart review of 140 posthysterectomy patients was conducted. Four strata were used to divide the sample records into one nonobstructive and three potentially obstructive conditions for surgery. A ratio of total intake divided by total output was formulated for each patient and compared between the groups. Statistically significant differences were shown by one-way analysis of variance between two of the obstructive groups and the nonobstructive group (F = 5.182; P < .05). Results of this research showed that certain obstructive conditions--uterine prolapse/endometrial cancer and leiomyomas greater than 15 week size--were linked with substantially higher postoperative urine outputs, which increase the risk of hypovolemia.
Asunto(s)
Deshidratación/etiología , Diuresis , Histerectomía/efectos adversos , Complicaciones Posoperatorias/etiología , Trastornos Urinarios/etiología , Enfermedades Uterinas/complicaciones , Enfermedades Uterinas/cirugía , Adulto , Anciano , Análisis de Varianza , Femenino , Humanos , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
This study of 197 college student participants found that marital infidelity is significantly more unacceptable than dating infidelity. Men tended to be more lenient in their ratings of infidelity than women. Self-esteem scores were significantly higher for individuals who did not become involved in dating infidelity than for participants who did. However, self-esteem was not found to be a significant factor in whether a person remained in a current relationship in which the partner had been unfaithful.
Asunto(s)
Actitud , Cortejo , Relaciones Extramatrimoniales , Adulto , Análisis de Varianza , Distribución de Chi-Cuadrado , Femenino , Humanos , Masculino , Autoimagen , Factores Sexuales , Sudeste de Estados UnidosRESUMEN
It has been estimated that as many as 250,000 adolescents are using anabolic steroids (AS). Recently, anecdotal reports suggest that athletes may also be using human growth hormone (HGH). The purpose of the present study was to determine the following: 1) if adolescents in two suburban midwestern high schools (83% white, 14% Asian, and 3% black) were using HGH; 2) knowledge of its effects; 3) reasons for use; and 4) concurrent AS use. After we obtained informed written consent, 224 male and 208 female 10th-grade students were surveyed using a 15-item questionnaire. Of male students surveyed, 5% (n = 11) reported past or present use of HGH, and one female student reported use. Our data suggest that among male adolescents surveyed, a majority had heard of this substance, and 31% of males reported knowing someone who was using HGH. Chi-square analysis found a significant association between AS and HGH use where seven AS users reported past or present use of HGH. Most HGH users were unaware of its side effects and reported first use between 14 and 15 years of age. No differences in sports activity, ethnicity, or age were found between users and nonusers of HGH.