No adverse prognostic influence of hepatitis B virus infection in acute childhood lymphoblastic leukemia

In the years 1980-1985 72 children with acute lymphoblastic leukemia were diagnosed and treated by intensive combination chemotherapy (BFM protocols 79, 81, 83). Of these children 33 acquired a Hepatitis B-virus-carrier state with 1983 as the peak year of incidence. Both groups of patients, the infected and the uninfected ones, were comparable as to prognostic factors. All except 8 patients are off chemotherapy after a total duration of treatment of 1 1/2 or 2 years. Probability for event-free survival (life table analysis, maximum observation time 82 months, minimum 12 months) is equal (0.77 vs. 0.75) in both groups. With 3 exceptions, all HBV-infected patients still carry the HBs-antigen in the serum; 22 of the 30 living patients in the infected group developed anti-HBc.     

Comparison between the effects of diallyl tetrasulfide on human retina pigment epithelial cells (ARPE-19) and HCT116 cells

Background

Diallyl mono- and polysulfanes from garlic are known to induce an adaptive cell response and the formation of antioxidants in cancer cells. In the case of a severe ER stress and a failure in the response, cancer cells eventually go into apoptosis. Only little is known about the response of normal cells upon treatment.

Methods

Normal ARPE-19 cells were treated with diallyl tetrasulfide to study their cellular response and the results were compared with those of HCT116 cancer cells. Cell viability was checked by an MTT assay and cytofluorimetry. The formation of superoxide radicals, H₂O₂ and thiols were determined and proteins involved in the ER stress response were also detected by Western blot analysis.

Results

We found that diallyl tetrasulfide induced reactive oxygen species (ROS) in normal cells similar to cancer cells in a time (0 to 60 min) and dose dependent manner (0 to 50 μM). The level of heme oxigenase-1 (HO-1) was up-regulated in both cell types. Initially, we found a decrease in the total thiol level in both cell types but in contrast to cancer cells, normal cells recovered from the decrease in the total thiol concentration within 60 min of treatment.

Conclusions

The recovery of the thiol concentration in normal cells treated with diallyl tetrasulfide seems to be responsible for the failure to induce the ER stress signalling pathway and finally apoptosis in normal cells.

General Significance

The difference in the recovery of the thiol status might be an explanation for the anti-carcinogenic effects of garlic compounds.     

Tetraamine‐modified octreotide and octreotate: labeling with 99mTc and preclinical comparison in AR4‐2J cells and AR4‐2J tumor‐bearing mice

Two somatostatin analogues, [^99mTc]Demotide and [^99mTc]Demotate 4, were compared with [^99mTc]Demotate 1, a previously reported somatostatin receptor subtype 2 (sst₂) targeting tracer. Conjugates were prepared by coupling an open‐chain tetraamine chelator to D ‐Phe¹ of [Tyr³]‐octreotide or [Tyr³]‐octreotate, respectively, via a p‐benzylaminodiglycolic acid spacer adopting solid‐phase peptide synthesis techniques. Peptide conjugates were collected in a highly pure form after chromatographic purification. Eventually, [^99mTc]Demotide and [^99mTc]Demotate 4 were obtained in ～1 Ci/µmol specific activity and >96% purity after labeling under alkaline conditions. Demotide and Demotate 4 exhibited similar high binding affinities for the sst₂ expressed in AR4‐2J cells with IC₅₀ values 0.16 and 0.10 nM, respectively. The (radio)metallated analogues [^99mTc]Demotide and [^99mTc]Demotate 4 showed equally high affinities to the sst₂ during saturation binding assays in AR4‐2J cell membranes (K_ds 0.08 and 0.07 nM, respectively). During incubation at 37 °C with AR4‐2J cells, the radiopeptides internalized effectively via a receptor‐mediated process, with [^99mTc]Demotate 4 exhibiting a faster internalization rate than [^99mTc]Demotide. After injection in athymic mice bearing sst₂‐expressing AR4‐2J tumors, the radiotracers showed high and specific uptake in the tumor (>25%ID/g at 1 h) and in the sst₂–positive organs. However, both [^99mTc]Demotide and [^99mTc]Demotate 4 showed unfavorably higher background activity, especially in the abdomen, in comparison to [^99mTc]Demotate 1 and are, therefore, less suited than [^99mTc]Demotate 1 for sst₂‐targeted tumor imaging in man. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.     

Highly conserved residues Asp-197 and His-250 in Agp1 phytochrome control the proton affinity of the chromophore and Pfr formation

The mutants H250A and D197A of Agp1 phytochrome from Agrobacterium tumefaciens were prepared and investigated by different spectroscopic and biochemical methods. Asp-197 and His-250 are highly conserved amino acids and are part of the hydrogen-bonding network that involves the chromophore. Both substitutions cause a destabilization of the protonated chromophore in the Pr state as revealed by resonance Raman and UV-visible absorption spectroscopy. Titration experiments demonstrate a lowering of the pK(a) from 11.1 (wild type) to 8.8 in H250A and 7.2 in D197A. Photoconversion of the mutants does not lead to the Pfr state. H250A is arrested in a meta-Rc-like state in which the chromophore is deprotonated. For H250A and the wild-type protein, deprotonation of the chromophore in meta-Rc is coupled to the release of a proton to the external medium, whereas the subsequent proton re-uptake, linked to the formation of the Pfr state in the wild-type protein, is not observed for H250A. No transient proton exchange with the external medium occurs in D197A, suggesting that Asp-197 may be the proton release group. Both mutants do not undergo the photo-induced protein structural changes that in the wild-type protein are detectable by size exclusion chromatography. These conformational changes are, therefore, attributed to the meta-Rc --> Pfr transition and most likely coupled to the transient proton re-uptake. The present results demonstrate that Asp-197 and His-250 are essential for stabilizing the protonated chromophore structure in the parent Pr state, which is required for the primary photochemical process, and for the complete photo-induced conversion to the Pfr state.     

Allozymic characterization and evolutionary relationships in the BrazilianAkodon cursor species group (Rodentia-Cricetidae)

The present study involved an electrophoretic survey of 22 protein loci in 269 individuals belonging to three species of the genusAkodon, A. aff.cursor (2n=16),A. cursor (2n=14/15), andA. montensis (2n=24/25/26), collected in Eastern Brazil. The joint results of gene diversity, genetic distances, phenetic analyses, and phylogenetic trees suggested thatA. aff.cursor has recently separated fromA. cursor and that the three species have experienced a recent chromosomal divergence followed by low allozyme differentiation. These data are in agreement with their classification as sibling species.     

Metabolomics of dietary Fatty Acid restriction in patients with phenylketonuria

Background

Patients with phenylketonuria (PKU) have to follow a lifelong phenylalanine restricted diet. This type of diet markedly reduces the intake of saturated and unsaturated fatty acids especially long chain polyunsaturated fatty acids (LC-PUFA). Long-chain saturated fatty acids are substrates of mitochondrial fatty acid oxidation for acetyl-CoA production. LC-PUFA are discussed to affect inflammatory and haemostaseological processes in health and disease. The influence of the long term PKU diet on fatty acid metabolism with a special focus on platelet eicosanoid metabolism has been investigated in the study presented here.

Methodology/Principal Findings

12 children with PKU under good metabolic control and 8 healthy controls were included. Activated fatty acids (acylcarnitines C6–C18) in dried blood and the cholesterol metabolism in serum were analyzed by liquid chromatographic tandem mass spectrometry (LC-MS/MS). Fatty acid composition of plasma glycerophospholipids was determined by gas chromatography. LC-PUFA metabolites were analyzed in supernatants by LC-MS/MS before and after platelet activation and aggregation using a standardized protocol. Patients with PKU had significantly lower free carnitine and lower activated fatty acids in dried blood compared to controls. Phytosterols as marker of cholesterol (re-) absorption were not influenced by the dietary fatty acid restriction. Fatty acid composition in glycerophospholipids was comparable to that of healthy controls. However, patients with PKU showed significantly increased concentrations of y-linolenic acid (C18:3n-6) a precursor of arachidonic acid. In the PKU patients significantly higher platelet counts were observed. After activation with collagen platelet aggregation and thromboxane B₂ and thromboxane B₃ release did not differ from that of healthy controls.

Conclusion/Significance

Long-term dietary fatty acid restriction influenced the intermediates of mitochondrial beta-oxidation. No functional influence on unsaturated fatty acid metabolism and platelet aggregation in patients with PKU was detected.