RESUMEN
For small non-hibernating mammals, a high thermogenic capacity is important to increase activity levels in the cold. It has been previously reported that lactating females decrease their thermogenic activity of brown adipose tissue (BAT), whereas their capacity to cope with extreme cold remains uncertain. In this study we examined food intake, body temperature and locomotor behavior, resting metabolic rate, non-shivering thermogenesis, and cytochrome c oxidase activity, and the rate of state 4 respiration of liver, skeletal muscle, and BAT in striped hamsters (Cricetulus barabensis) at peak lactation and non- breeding hamsters (controls). The lactating hamsters and non- breeding controls were acutely exposed to -15°C, and several markers indicative of thermogenic capacity were examined. In comparison to non-breeding females, lactating hamsters significantly increased food intake and body temperature, but decreased locomotor behavior, and the BAT mass, indicative of decreased BAT thermogenesis at peak lactation. Unexpectedly, lactating hamsters showed similar body temperature, resting metabolic rate, non-shivering thermogenesis with non-breeding females after acute exposure to -15°C. Furthermore, cytochrome c oxidase activity of liver, skeletal muscle and BAT, and serum thyroid hormone concentration, and BAT uncoupling protein 1 expression, in lactating hamsters were similar with that in non-breeding hamsters after acute extreme cold exposure. This suggests that lactating females have the same thermogenic capacity to survive cold temperatures compared to non-breeding animals. This is particularly important for females in the field to cope with cold environments during the period of reproduction. Our findings indicate that the females during lactation, one of the highest energy requirement periods, do not impair their thermogenic capacity in response to acute cold exposure.
RESUMEN
Food resource availability is one of the most important factors affecting interindividual competition in a variety of animal species. However, the energy budget and territory aggression strategy of small mammals during periods of food restriction remain uncertain. In this study, metabolic rate, body temperature, territory aggression behavior, and fat deposit were measured in male striped hamster (Cricetulus barabensis) restricted by 20% of ad libitum food intake with or without supplementary methimazole. Serum thyroid hormone (tri-iodothyronine, T3 and thyroxine, T4), and cytochrome c oxidase (COX) activity in liver, brown adipose tissue, and skeletal muscle, were also measured. Attack latency, total attack times and duration, and the interval duration between attacks of resident hamsters were not significantly changed during food restriction, which was not significantly affected by supplementary methimazole. Metabolic rate and body temperature was significantly increased in food-restricted hamsters following introduction of an intruder, which was not completely blocked by supplementary methimazole. Serum T3 and T4 levels and BAT COX activity were not significantly changed following aggression, and were significantly decreased by supplementary methimazole. These findings suggest that striped hamsters increase energy expenditure for territory aggression during food restriction, and consequently lead to excessive energy depletion. Territory aggression behavior may decrease the capacity to cope with food shortage, which may be independent of thyroid hormone.
Asunto(s)
Tejido Adiposo Pardo , Metimazol , Tejido Adiposo Pardo/fisiología , Agresión , Animales , Cricetinae , Cricetulus , Metabolismo Energético/fisiología , Masculino , Metimazol/metabolismo , Hormonas TiroideasRESUMEN
Case (description): A 52-year-old male patient presented with seizures on the 16th day post liver transplantation suggesting tacrolimus-associated posterior reversible encephalopathy syndrome (PRES). On the 18th day, the patient was diagnosed with graft-versus-host disease (GVHD). Calcineurin inhibitor (CNI) was stopped and the patient received 1 g methylprednisolone and 25 g immunoglobulin. However, on the 21st day, the patient's clinical condition progressively worsened and he died of multi-organ failure. GVHD could have occurred with PRES because the CNI dose was reduced. The best treatment for patients with PRES and GVHD is using immunosuppressants other than CNI. Antibody preparations and steroids could be a standard treatment.
Asunto(s)
Enfermedad Injerto contra Huésped/etiología , Trasplante de Hígado/efectos adversos , Síndrome de Leucoencefalopatía Posterior/etiología , Inhibidores de la Calcineurina/efectos adversos , Enfermedad Injerto contra Huésped/terapia , Humanos , Masculino , Persona de Mediana Edad , Síndrome de Leucoencefalopatía Posterior/terapia , Tacrolimus/efectos adversosRESUMEN
OBJECTIVE: The purpose of this study was to describe the population pharmacokinetics (PK) of tacrolimus (TAC) in 52 Chinese pediatric patients early after liver transplantation. METHODS: Details of drug dose, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data from the first day after surgery. A total of 488 concentration data were obtained and analyzed by a nonlinear mixed-effect modeling (NONMEM) method. A number of demographic and clinical variables were tested for their influence on TAC PK parameters. RESULTS: The PK of TAC were best described by a one-compartment model with first-order absorption and elimination. Apparent clearance (CL/F) and apparent volumes of distribution (V/F) in final population model were 5.72 L/h and 131 L, respectively. The absorption rate constant (Ka) was fixed in 4.48 h-1. The inter-individual variabilities in CL/F and V/F were 13.5% and 78.1%. In the final analysis performed in all 52 patients, the post-operation day (POD) and alanine aminotransferase (ALT) influenced TAC CL/F and V/F, and total protein (TP) was the only covariate retained on V/F. CONCLUSION: A population PK model of TAC was developed in Chinese pediatric patients early after liver transplantation. It identified significant relationships between the PK of TAC and the characteristics of the patients. POD, ALT, and TP were identified as the main factors influencing the PK of TAC. The developed model could be useful to optimize individual pediatric TAC dosing regimen in routine clinical practice.
Asunto(s)
Rechazo de Injerto/prevención & control , Inmunosupresores/farmacocinética , Trasplante de Hígado , Modelos Biológicos , Tacrolimus/farmacocinética , Administración Oral , Adolescente , Factores de Edad , Área Bajo la Curva , Pueblo Asiatico , Niño , Preescolar , China , Esquema de Medicación , Monitoreo de Drogas , Femenino , Rechazo de Injerto/sangre , Rechazo de Injerto/etnología , Rechazo de Injerto/inmunología , Supervivencia de Injerto/efectos de los fármacos , Humanos , Inmunosupresores/administración & dosificación , Inmunosupresores/sangre , Lactante , Trasplante de Hígado/efectos adversos , Masculino , Tasa de Depuración Metabólica , Dinámicas no Lineales , Reproducibilidad de los Resultados , Estudios Retrospectivos , Tacrolimus/administración & dosificación , Tacrolimus/sangre , Resultado del TratamientoRESUMEN
The aim of this study was to induce type 2 diabetes in tree shrew (Tupaia belangeri chinensis). Streptozotocin (STZ), a glucosamine derivative of nitrosourea and preferentially toxic to pancreatic beta cells, has been commonly used to induce type 1 and 2 diabetes in experimental animals. Tree shrews were treated with different low doses of STZ (60, 70, and 80 mg/kg), with six control tree shrews receiving citrate buffer. After STZ injection, tree shrews displayed increased fasting blood and urine glucose, impaired oral glucose tolerance test, and disturbed lipids metabolism and renal function. However, STZ induced tree shrews showed no diabetic complications such as diabetic lactic acidosis and hyperglycemic hyperosmolar. Animals with the above type 2 diabetic-like symptoms were variable across the three groups from 66.7% to 100%, and mortality ranged from 16.7% to 33.3%. Thus, two 80 mg/kg STZ dose injections were appeared more appropriate than other doses to induce tree shrew model of type 2 diabetes. Our results demonstrated that type 2 diabetes could be induced with favorable STZ application in tree shrew.