Tolerance space and molecular similarity

Molecular similarity methods were used in selecting K nearest neighbors and in estimating mutagenicity of 95 aromatic amines and boiling points of a large set of over 2,900 compounds. Similarity is analyzed in terms of the concept of tolerance space. Specifically, the role of non-transitivity of the tolerance relation in estimating properties using similarity methods is examined.     

Upregulation of 5''-AMP-activated protein kinase is responsible for the increase in myocardial fatty acid oxidation rates following birth in the newborn rabbit

Eighteen patients with intracranial skull base tumours diagnosed at CT or MR as neuromas or meningiomas were studied with positron emission tomography (PET) using L-(methyl-11C) methionine. Compared with normal cerebellar tissue, the uptake of methionine in the tumours increased more rapidly and reached a higher level, and showed a slow decline after a peak occurring about 5 min after the injection. All the meningiomas exhibited considerably higher accumulation of the tracer compared with the surrounding cerebellar tissue, which made the tumour easy to identify and to demarcate from the surrounding cerebellar tissue, which made the tumour easy to identify and to demarcate from the surrounding structures (tumour to cerebellum ratios 2.62-5.37, mean 3.63). The uptake was homogeneous in all meningiomas, which were all of the syncytial type. The neuromas showed lower contrast against the cerebellum (tumour to cerebellum ratios 1.1-1.87, mean 1.48). Some neuromas displayed an irregular pattern with regions of decreased tracer uptake corresponding to small cystic areas within the neuroma. There was no overlap in methionine uptake between the two tumour groups. The results indicate that PET-methionine may contribute to the evaluation, treatment planning and follow-up of patients with skull base meningiomas and neuromas.     

A subpopulation of reactive astrocytes at the immediate site of cerebral cortical injury

Data presented in this paper show that bromhexine and its pharmacologically active metabolite can easily be determined by capillary zone electrophoresis. The composition of the running buffer had a significant effect on the reproducibility of the migration time for which a carrier solution containing 30 mM phosphate buffer (pH 3.0), 5 M urea and 10% (v/v) acetonitrile was used. The method was validated with respect to its response linearity and reproducibility. The method is suitable for the determination of bromhexine and ambroxol in several samples such as pharmaceuticals, urine and serum. Photodiode-array detection permitted the rapid identification of both drugs in the sample analyzed.     

Intraoperative arthrography and the Ilizarov technique. Role in the correction of paediatric deformity and leg lengthening

We performed intraoperative arthrography of the knee in 12 children with congenital short femur, Blount's disease or Ollier's disease in whom the Ilizarov technique was used for correction of deformity, leg lengthening or both. In each case, arthrography revealed a joint surface considerably different from that assumed from plain radiographs, and resulted in a change in the placement of our reference wires before application of the frame. This gave significant improvement in the mechanical axis obtained at the time of removal of the frame. The technique is safe, cheap and easy to perform. It is a useful adjunct to the application of the Ilizarov frame when used for complex lengthening and correction of deformity in the leg.     

Cellular levels of factor 390 and methanogenic enzymes during growth of Methanobacterium thermoautotrophicum deltaH

Methanobacterium thermoautotrophicum deltaH was grown in a fed-batch fermentor and in a chemostat under a variety of 80% hydrogen-20% CO2 gassing regimes. During growth or after the establishment of steady-state conditions, the cells were analyzed for the content of adenylylated coenzyme F420 (factor F390-A) and other methanogenic cofactors. In addition, cells collected from the chemostat were measured for methyl coenzyme M reductase isoenzyme (MCR I and MCR II) content as well as for specific activities of coenzyme F420-dependent and H2-dependent methylenetetrahydromethanopterin dehydrogenase (F420-MDH and H2-MDH, respectively), total (viologen-reducing) and coenzyme F420-reducing hydrogenase (FRH), factor F390 synthetase, and factor F390 hydrolase. The experiments were performed to investigate how the intracellular F390 concentrations changed with the growth conditions used and how the variations were related to changes in levels of enzymes that are known to be differentially expressed. The levels of factor F390 varied in a way that is consistently understood from the biochemical mechanisms underlying its synthesis and degradation. Moreover, a remarkable correlation was observed between expression levels of MCR I and II, F420-MDH, and H2-MDH and the cellular contents of the factor. These results suggest that factor F390 is a reporter compound for hydrogen limitation and may act as a response regulator of methanogenic metabolism.