From prompt gamma distribution to dose: a novel approach combining an evolutionary algorithm and filtering based on Gaussian-powerlaw convolutions.

Range verification and dose monitoring in proton therapy is considered as highly desirable. Different methods have been developed worldwide, like particle therapy positron emission tomography (PT-PET) and prompt gamma imaging (PGI). In general, these methods allow for a verification of the proton range. However, quantification of the dose from these measurements remains challenging. For the first time, we present an approach for estimating the dose from prompt γ-ray emission profiles. It combines a filtering procedure based on Gaussian-powerlaw convolution with an evolutionary algorithm. By means of convolving depth dose profiles with an appropriate filter kernel, prompt γ-ray depth profiles are obtained. In order to reverse this step, the evolutionary algorithm is applied. The feasibility of this approach is demonstrated for a spread-out Bragg-peak in a water target.

Identification of atypical strains of Staphylococcus epidermidis by use of molecular tools.

Four atypical coagulase-negative staphylococcal (CNS) isolates from clinical sources were compared with Staphylococcus epidermidis strains by ribotyping. The ribotypes of the four strains shared close rDNA restriction profiles with those of the S. epidermidis strains used. The DNA sequence encoding 16S rRNA demonstrated 99.9% homology with S. epidermidis. S1 nuclease experiments showed that these atypical strains formed a homogeneous genomic group. DNA-DNA homologies between the S. epidermidis type strain CCM 2124 and the four CNS isolates ranged from 70 to 89%. The guanine-plus-cytosine content of the deoxyribonucleic acid of the four strains ranged from 31 to 32 mol%.

The cAMP-binding ectoprotein from Saccharomyces cerevisiae is membrane-anchored by glycosyl-phosphatidylinositol.

Saccharomyces cerevisiae contains an amphiphilic cAMP-binding glycoprotein at the outer face of the plasma membrane (M(r) = 54,000). It is converted to a hydrophilic form by treatment with glycosyl-phosphatidylinositol-specific phospholipases C and D (GPI-PLC/D), suggesting membrane anchorage by a covalently bound glycolipid. Determination of the constituents of the purified anchor by gas-liquid chromatography and amino acid analysis reveals the presence of glycerol, myo-inositol, glucosamine, galactose, mannose, ethanolamine, and asparagine (as the carboxyl-terminal amino acid of the Pronase-digested protein to which the anchor is attached). Complementary results are obtained by metabolic labeling, indicating that fatty acids and phosphorus are additional anchor constituents. The phosphorus is resistant to alkaline phosphatase, whereas approximately half is lost from the protein after treatment with GPI-PLD or nitrous acid, and all is removed by aqueous HF indicating the presence of two phosphodiester bonds. Inhibition of N-glycosylation by tunicamycin or removal of protein-bound glycan chains by N-glycanase or Pronase does not abolish radiolabeling of the anchor structure by any of the above compounds. Analysis of the products obtained after sequential enzymic and chemical degradation of the anchor agrees with the arrangement of constituents in GPIs from higher eucaryotes. Evidence for anchorage of the yeast cAMP-binding protein by a GPI anchor is strengthened additionally by the reactivity of the GPI-PLC-cleaved anchor with antibodies directed against the cross-reacting determinant of trypanosomal variant surface glycoproteins.

[Peripheral oxygen saturation during dental surgery with and without premedication]. / Periphere Sauerstoffsättigung bei zahnärztlich-chirurgischen Eingriffen mit und ohne Prämedikation.

83 adults undergoing dental surgical procedures in local anesthesia were monitored continuously with a pulse oximeter for hypoxemia. 30 patients received as premedication either a combination of a neuroleptic drug and an opiate or a benzodiazepine. There was a drop in the oxygen saturation in 80% of the patients with premedication but only in 66% of the patients without. There were statistical highly significant more periods of hypoxemia in patients with premedication compared to the others. (1548 periods versus 659 periods p less than 0.001). The kind of premedication/sedation does not influence the number of hypoxic episodes. We conclude that especially patients with premedication should only be treated by surgeons with sufficient clinical experience in coping with emergency situations.