RESUMEN
Repeated administration of psychostimulant drugs or stress can elicit a sensitized response to the stimulating and reinforcing properties of the drug. Here we explore the mechanisms in the nucleus accumbens (NAc) whereby an acute restraint stress augments the acute locomotor response to cocaine. This was accomplished by a combination of behavioral pharmacology, microdialysis measures of extracellular dopamine and glutamate, and Western blotting for GluR1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor (AMPAR). A single exposure to restraint stress 3 weeks before testing revealed that enduring locomotor sensitization to cocaine was paralleled by an increase in extracellular dopamine in the core, but not the shell subcompartment, of the NAc. Wistar rats pre-exposed to acute stress showed increased basal levels of glutamate in the core, but the increase in glutamate by acute cocaine was blunted. The alterations in extracellular glutamate seem to be relevant, as blocking AMPAR by 6-cyano-7-nitroquinoxaline-2,3-dione microinjection into the core prevented both the behavioral cross-sensitization and the augmented increase in cocaine-induced extracellular dopamine. Further implicating glutamate, the locomotor response to AMPAR stimulation in the core was potentiated, but not in the shell of pre-stressed animals, and this was accompanied by an increase in NAc GluR1 surface expression. This study provides evidence that the long-term expression of restraint stress-induced behavioral cross-sensitization to cocaine recapitulates some mechanisms thought to underpin the sensitization induced by daily cocaine administration, and shows that long-term neurobiological changes induced in the NAc by acute stress are consequential in the expression of cross-sensitization to cocaine.
Asunto(s)
Sensibilización del Sistema Nervioso Central , Estimulantes del Sistema Nervioso Central/farmacología , Cocaína/farmacología , Dopamina/metabolismo , Ácido Glutámico/metabolismo , Núcleo Accumbens/fisiología , Estrés Psicológico/metabolismo , 6-Ciano 7-nitroquinoxalina 2,3-diona/farmacología , Animales , Exocitosis , Expresión Génica , Locomoción/efectos de los fármacos , Masculino , Neuronas/metabolismo , Núcleo Accumbens/metabolismo , Transporte de Proteínas , Ratas , Ratas Wistar , Receptores AMPA/antagonistas & inhibidores , Receptores AMPA/genética , Receptores AMPA/metabolismo , Restricción FísicaRESUMEN
Faeces similarity among sympatric felid species has generally hampered their use in distributional, demographic and dietary studies. Here, we present a new and simple approach based on a set of species-specific primers, for the unambiguous identification of faeces from sympatric neotropical felids (i.e. puma, jaguar, jaguarundi and ocelot/ margay). This method, referred to as rapid classificatory protocol-PCR (RCP-PCR), consists of a single-tube multiplex PCR yielding species-specific banding patterns on agarose gel. The method was optimized with samples of known origin (14 blood and 15 fresh faeces) and validated in faecal samples of unknown origin (n = 138), for some of which (n = 40) we also obtained species identification based on mtDNA sequencing. This approach proved reliable and provides high identification success rates from faeces. Its simplicity and cost effectiveness should facilitate its application for routine surveys of presence and abundance of these species.
Asunto(s)
Heces/química , Felidae/genética , Reacción en Cadena de la Polimerasa/métodos , Animales , América Central , ADN Mitocondrial/genética , Felidae/clasificación , América del Sur , Especificidad de la EspecieRESUMEN
The beneficial effects of moderate-intensity exercise on cardiorespiratory fitness and body composition are well documented, with the greatest health benefits reported in sedentary individuals who engage in moderate levels of exercise. The published literature contains no quantification of the threshold of lower limits of beneficial exercise or estimates of benefits derived from lower exercise levels. The specific aim of this study was to compare the effects of two walking frequencies, holding intensity and duration constant, on blood lipids, body composition, and exercise maintenance regimens of Mexican American women. A quasi-experimental design, with two treatment groups and one comparison group, was used to explore the dose-response effects of low-intensity exercise on cardiovascular outcomes. Significant interactions were found between walking and total serum cholesterol and skin-fold sums. This study demonstrated the clinical efficacy of a low-intensity exercise regimen on cardiovascular risk factors and exercise adherence.
Asunto(s)
Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/prevención & control , Americanos Mexicanos , Caminata , Población Blanca , Adolescente , Adulto , Composición Corporal , Colesterol/sangre , Femenino , Humanos , Persona de Mediana Edad , Obesidad/genética , Obesidad/prevención & control , Texas , Salud de la MujerRESUMEN
To evaluate the association between corneal lipid infiltration (corneal arcus) and dietary cholesterol in Cuban tree frogs (Osteopilus septentrionalis), 47 wild-caught frogs were fed diets of either regular or high-cholesterol crickets containing 0.7% and 1.7% cholesterol dry matter, respectively. Serum total cholesterol and triglycerides were measured when the frogs were euthanized after 17 mo. In a subsample of frogs, serum lipoproteins were characterized using high-performance liquid chromatography. The first case of corneal lipid deposition occurred in a female frog after 13 mo on the high-cholesterol diet. In the subsequent 4 mo, 5/11 males and 11/35 females developed the disease. Four of these affected frogs were females on the regular diet. Frogs with corneal lipid deposition had elevated serum total cholesterol (27.3 +/- 19.8 mmol/L) and low-density lipoproteins (LDL, 17.8 +/- 18.9 mmol/L) compared with unaffected captive frogs (16.5 +/- 20.4 and 9.0 +/- 7.6 mmol/L, respectively). Corneal lipid deposition was more prevalent in frogs on the high-cholesterol diet, and this group had higher serum total cholesterol (34.1 +/- 15.2 mmol/L in females, 22.8 +/- 14.8 mmol/L in males) than did frogs on the diet of regular crickets (12.3 +/- 8.7 mmol/L in females, 10.4 +/- 3.1 mmol/L in males). Captive frogs on both diets had higher serum total cholesterol than did wild frogs (3.1 +/- 2.1 mmo/L in females, 5.3 +/- 2.6 mmo/L in males). This additional serum cholesterol was primarily carried on very low-density lipoproteins (VLDL) and LDL rather than high-density lipoproteins (HDL), as indicated by the significantly higher ratio of VLDL cholesterol and LDL cholesterol over HDL cholesterol in captive frogs compared with wild frogs. Elevation in this ratio was significantly higher in captive females than in captive males. There was no evidence that increased serum cholesterol in captive females was directly related to the process of vitellogenesis.
Asunto(s)
Anuros/metabolismo , Colesterol en la Dieta/administración & dosificación , Enfermedades de la Córnea/veterinaria , Lipidosis/veterinaria , Lípidos/sangre , Animales , Animales Salvajes , Animales de Zoológico , Anuros/sangre , Colesterol/sangre , Colesterol en la Dieta/efectos adversos , Enfermedades de la Córnea/sangre , Enfermedades de la Córnea/etiología , Femenino , Metabolismo de los Lípidos , Lipidosis/sangre , Lipidosis/etiología , Masculino , Distribución Aleatoria , Estaciones del Año , Triglicéridos/sangre , Vitelogénesis/fisiologíaRESUMEN
OBJECTIVES: To describe the growth and nutritional status of a pediatric population with Bloom syndrome. STUDY DESIGN: Longitudinal growth data from 148 patients in the Bloom's Syndrome Registry (85 male, 63 female) were compiled retrospectively from physician and parent records to develop graphed statistics of weight-for-age, height-for-age, fronto-occipital circumference-for-age, and weight-for-height for both sexes with comparisons with the normal population. RESULTS: Term birth measurements confirm that the growth deficiency of Bloom syndrome has prenatal onset. Stunting persists throughout life, and an adolescent growth spurt is not apparent from the smoothed data. Growth continues by at least 1 cm/yr until age 21 years for both sexes. More than half of children with Bloom syndrome are significantly wasted until age 8 years, which is not related to early death or underlying malignancy. The mean body mass index for adults with Bloom syndrome after age 25 years is low normal (n = 22, mean = 20.2 kg/m2). CONCLUSIONS: Children with Bloom syndrome have significant growth retardation and wasting.
Asunto(s)
Síndrome de Bloom/fisiopatología , Trastornos del Crecimiento/fisiopatología , Trastornos Nutricionales/etiología , Adolescente , Adulto , Síndrome de Bloom/complicaciones , Síndrome de Bloom/etnología , Estatura , Índice de Masa Corporal , Peso Corporal , Niño , Preescolar , Femenino , Trastornos del Crecimiento/etnología , Trastornos del Crecimiento/etiología , Humanos , Lactante , Recién Nacido , Masculino , Estado Nutricional , Valores de Referencia , Sistema de Registros , Estudios Retrospectivos , Síndrome Debilitante/etiologíaRESUMEN
Measurement of regional fat has commonly been accomplished by extrapolation from anthropometric measures. Recent studies of White and Black women have demonstrated differences in intra-abdominal fat, using computerized tomographic (CT) techniques. These same estimates were computed for 48 Mexican American women who were undergoing CT for diagnostic purposes. Waist-hip ratios, waist-thigh ratios, and sagittal diameter index were also calculated. Four (7mm) CT slices between L-4 and L - 5 were analyzed with imaging software. The volume of both subcutaneous and visceral fat was estimated. Like other minority women, Mexican American women had less intra-abdominal fat than subcutaneous fat, which is important because of the association of excess intra-abdominal fat with cardiovascular risk. Intra-abdominal fat volume was significantly predicted by only one variable, sagittal abdominal diameter, while subcutaneous fat volume was predicted by hip and thigh circumferences.
Asunto(s)
Tejido Adiposo/anatomía & histología , Tejido Adiposo/diagnóstico por imagen , Antropometría , Pesos y Medidas Corporales/métodos , Americanos Mexicanos , Adulto , Antropometría/métodos , Constitución Corporal , Enfermedades Cardiovasculares/prevención & control , Femenino , Humanos , Persona de Mediana Edad , Texas , Tomografía Computarizada por Rayos X , Salud de la MujerRESUMEN
Advances in instrumentation have enabled laboratories to deliver results much more quickly. But as equipment has advanced so have expectations on turnaround time (TAT), driving up costs in the process. Laboratories must balance the needs of their clients against the need to cover their costs. In this issue, we asked our respondents: How do you address the issue of turnaround time?