Fatty liver and insulin resistance in obese Zucker rats: No role for mitochondrial dysfunction

The relationship between insulin resistance and mitochondrial function is of increasing interest. Studies looking for such interactions are usually made in muscle and only a few studies have been done in liver, which is known to be a crucial partner in whole body insulin action. Recent studies have revealed a similar mechanism to that of muscle for fat-induced insulin resistance in liver. However, the exact mechanism of lipid metabolites accumulation in liver leading to insulin resistance is far from being elucidated. One of the hypothetical mechanisms for liver steatosis development is an impairment of mitochondrial function. We examined mitochondrial function in fatty liver and insulin resistance state using isolated mitochondria from obese Zucker rats. We determined the relationship between ATP synthesis and oxygen consumption as well as the relationship between mitochondrial membrane potential and oxygen consumption. In order to evaluate the quantity of mitochondria and the oxidative capacity we measured citrate synthase and cytochrome c oxidase activities. Results showed that despite significant fatty liver and hyperinsulinemia, isolated liver mitochondria from obese Zucker rats display no difference in oxygen consumption, ATP synthesis, and membrane potential compared with lean Zucker rats. There was no difference in citrate synthase and cytochrome c oxidase activities between obese and lean Zucker rats in isolated mitochondria as well as in liver homogenate, indicating a similar relative amount of hepatic mitochondria and a similar oxidative capacity. Adiponectin, which is involved in bioenergetic homeostasis, was increased two-fold in obese Zucker rats despite insulin resistance. In conclusion, isolated liver mitochondria from lean and obese insulin-resistant Zucker rats showed strictly the same mitochondrial function. It remains to be elucidated whether adiponectin increase is involved in these results

Ultramicromethod for measuring the activity of terminal deoxynucleotidyl transferase.

Abstract We describe an ultramicromethod for measurement of terminal deoxynucleotidyl transferase activity. The materials used are as proposed by Hösli (Clin Chem 1977;23:1476-84) for antenatal diagnosis. The technique is based on the methods of Beutler and Kuhl (Am J Clin Pathol 1978;70:733-7) and Yasmineh et al. (Clin Chem 1980; 26:891-5). The procedure makes it possible to reduce the blood sample to 2 mL at the most and to reduce the cost of the measurement very considerably. The technique gives results similar to those given by the conventional techniques.</jats:p

Effect of Hirudin on the Chemotactic Properties of Alpha-Thrombin

A study by an agarose technique of the chemotactic power of human α-thrombin on polymorphonuclear leukocytes reveals that this enzyme has a chemotactic activity. Hirudin, which inhibits the coagulant properties of thrombin, suppresses these chemotactic properties. This effect could be explained by the binding of hirudin to the structural domain of α-thrombin involved in its chemotactic activity.</jats:p

Liquid Preservation of Polymorphonuclear Leukocytes: Effect of Various Additives on Chemotaxis Preservation

Peer Reviewe

Validation d’une méthode Elisa pour la recherche de l’antigène aspergillaire galactomannane en vue de l’accréditation

International audienceDiagnosis of invasive aspergillosis for patients with high risk of infection is based on the monitoring of Aspergillus antigenemia assessed by the detection of galactomannan in serum by a sandwich-type ELISA (Biorad(®)). The validation of the method was displayed according to the guide COFRAC SH GTA 04. The internal quality control system settled, involves two quality control samples made of pools of sera (negative and positive). The repeatability of the measurements, as estimated by the coefficients of variation (CV), obtained by two different technicians was found from 9 to 13.7% for the positive control. The CV of the negative control, for which the provider indicates it is not useful in the analytical process, was found from 7.1 to 30%. In our experience it could be an indicator of environmental contamination. The evaluation of the intermediary fidelity was 15.7% for the positive control and 22.5% for the negative one. In the lack of reference material (International Standard) and recommendation from scientific societies, performances obtained will be discussed according to the results reported in the technical form of the supplier and those obtained by 39 laboratories participating in the only available external quality assessment program organized in France by ProBioQual(®) where the CV of reproducibility are 44.7% of unit (mean index 0.131) for the negative control and 18% (mean index 1.089) for the positive one in 2011