Experimental studies of transient mass transfer and reaction in the liver: interpretation with a heterogeneous compartment model.

The uptake and metabolism of lipophilic compounds by the liver were studied by administering a model compound, lidocaine, to the isolated rat liver. Lidocaine was continuously infused into the liver until steady state was reached. Subsequent step changes in the inlet concentration were used to obtain information on rates of cellular uptake and release and to assess the extent of mixing within the organ. A simple heterogeneous model combining mass transfer and enzyme reactions was required to simulate the effluent levels of lidocaine and two primary metabolites, monoethylglycinexylidide and 3-hydroxylidocaine. The rate constants for uptake and release of lidocaine were 1200 and 46 min-1, respectively. The rate-limiting step was intracellular reaction, with a rate constant of 0.49 min-1. Although the rate of lidocaine uptake was fast, it was 50 times slower than the rate of facilitated uptake of galactose, a fact suggesting passive transport of lidocaine between the tissue and the vasculature. The rates of mass transfer of lidocaine and its metabolites differed, but the ratios of the rate of uptake to the rate of release were the same. The results suggested that all three species had an affinity for the cellular region of the liver; concentrations in tissue were approximately five times greater than concentrations in effluent. Because of the large capacity of the organ for uptake of lidocaine and its metabolites, concentrations from washout experiments were controlled by linear mass transfer from the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fetal intracranial teratoma: US diagnosis of three cases and a review of the literature

We describe three cases of fetal intracranial teratoma diagnosed by ultrasound and review the literature. Sonographic features include cranial enlargement, gross distortion of normal cerebral architecture by a hyperechoic, multicystic mass, and polyhydramnios. Despite early diagnosis, the cesarean section rate is high and the overall prognosis is dismal.     

Role of insulin in thermogenic responses to refeeding in 3-day-fasted rats

Refeeding 3-day-fasted rats with 40 kJ carbohydrate (CHO; corn flour) or protein (gelatin) caused a rise in plasma insulin levels 3 h later, but refeeding fat or injection of norepinephrine (400 micrograms/kg) had no effect. Injection of insulin (0.25 U) caused a 15% rise in metabolic rate 24 h later in fasted rats that could be inhibited by treatment with propranolol. Refeeding rats with a single CHO meal produced an increase in oxygen consumption (15%) 24 h later that was inhibited by injection of diazoxide or 2-deoxy-D-glucose given at the time of the meal. The thermogenic response to insulin injection was unaffected by treatment with diazoxide or 2-deoxy-D-glucose. Genetically obese Zucker rats failed to increase metabolic rate after insulin or CHO. In normally fed lean rats, maintained on a stock diet or a palatable cafeteria diet, insulin (4 U) enhanced the thermogenic response to norepinephrine and stimulated resting metabolic rate (16%) in the cafeteria-fed rats. These data suggest that insulin is involved in the thermogenic responses to food and catecholamines.     

Complementary medicine use by men with prostate cancer: a systematic review of prevalence studies

Men with prostate cancer are reported as commonly using complementary and alternative medicine (CAM) but surveys have not recently been subjected to a rigorous systematic review incorporating quality assessment. Six electronic databases were searched using pre-defined terms. Detailed information was extracted systematically from each relevant article. Study reporting quality was assessed using a quality assessment tool, which demonstrated acceptable inter-rater reliability and produces a percentage score. In all, 42 studies are reviewed. All were published in English between 1999 and 2009; 60% were conducted in the United States. The reporting quality was mixed (median score = 66%, range 23-94%). Significant heterogeneity precluded formal meta-analysis. In all, 39 studies covering 11,736 men reported overall prevalence of CAM use; this ranged from 8 to 90% (median=30%). In all, 10 studies reported prevalence of CAM use specifically for cancer care; this ranged from 8 to 50% (median = 30%). Some evidence suggested CAM use is more common in men with higher education/incomes and more severe disease. The prevalence of CAM use among men with prostate cancer varies greatly across studies. Future studies should use standardised and validated data collection techniques to reduce bias and enhance comparability.