High resolution nuclear magnetic resonance spectroscopy of glycosphingolipids. I: 360 MHz 1H and 90.5 MHz 13C NMR analysis of galactosylceramides

The high resolution ¹H and ¹³C nuclear magnetic resonance (NMR) spectra of galactosylceramides containing n-fatty acids and α-hydroxy fatty acids were recorded in dimethylsulfoxide solution with and without addition of D₂O. From the coupling constants of the sugar ring protons, a ⁴C₁ conformation can be deduced. In contrast to the conformation in aqueous solution, the C⁶ hydroxymethylene group is freely rotating around the C⁶C⁵ bond. In the ceramide residue all signals produced by protons linked to carbons bearing electronegative substituents could be attributed. The large difference in coupling constants of the methylene protons of C^1′ to the C^2′ methine proton of the sphingosine indicates a restricted rotation around the C^1′C^2′ bond. The assignments of the hydroxy and amino protons follow from the decoupling of the corresponding methine protons.     

Properties and regulation of organic cation transport in freshly isolated human proximal tubules.

The kidney, and more specifically the proximal tubule, is the main site of elimination of cationic endogenous metabolites and xenobiotics. Although numerous studies exist on renal organic cation transport of rat and rabbit, no information is available from humans. Therefore, we examined organic cation transport and its regulation across the basolateral membrane of isolated human proximal tubules. mRNA for the cation transporters hOCT1 and hOCT2 as well as hOCTN1 and hOCTN2 was detected in these tubules. Organic cation transport across the basolateral membrane of isolated collapsed proximal tubules was recorded with the fluorescent dye 4-(4-dimethylamino)styryl-N-methylpyridinium (ASP(+)). Depolarization of the cells by rising extracellular K(+) concentration to 145 mm reduced ASP(+) uptake by 20 +/- 5% (n = 15), indicating its electrogeneity. The substrates of organic cation transport tetraethylammonium (K(i) = 63 microm) and cimetidine (K(i) = 11 microm) as well as the inhibitor quinine (K(i) = 2.9 microm) reduced ASP(+) uptake concentration dependently. Maximal inhibition reached with these substances was approximately 60%. Stimulation of protein kinase C with 1,2-dioctanoyl-sn-glycerol (DOG, 1 microm) or ATP (100 microm) inhibited ASP(+) uptake by 30 +/- 3 (n = 16) and 38 +/- 13% (n = 6), respectively. The effect of DOG could be reduced with calphostin C (0.1 microm, n = 7). Activation of adenylate cyclase by forskolin (1 microm) decreased ASP(+) uptake by 29 +/- 3% (n = 10). hANP (10 nm) or 8-bromo-cGMP (100 microm) also decreased ASP(+) uptake by 17 +/- 3 (n = 9) or 32 +/- 5% (n = 10), respectively. We show for the first time that organic cation transport across the basolateral membrane of isolated human proximal tubules, most likely mediated via hOCT2, is electrogenic and regulated by protein kinase C, the cAMP- and the cGMP-dependent protein kinases.     

Individual variability and population regulation: an individual-based model

To study the influence of individual variability on population dynamics an individual-based model of the dynamics of a single population consisting of different individuals is constructed. The model is based on differences in individual assimilation rates due to intraspecific competition and variability of initial weights. The model exhibits "imperfect regulation", i.e., the number of individuals in the population oscillates and sooner or later the population becomes extinct. When individual variability is included, the model produces longer population extinction times than without individual variability. The average extinction time is not however a monotonic function of the degree of individual variability.     

Discrimination of the redfish (Sebastes mentella) stock components in the Irminger Sea and adjacent waters based on meristics,morphometry and biological characteristics

Redfish Sebastes mentella samples were collected in 2004 and 2005 during commercial cruises to the Irminger Sea on board the Polish vessel M/T ‘Wiesbaden’. Ichthyological studies included length and weight measurements, sex, gonad maturity stages and age determinations. Meristic and morphometric measurements were performed on digital images of the redfish. Comparison of the pelagic redfish from the northeastern (depths deeper than 500 m) and southwestern (depths shallower than 500 m) fishing grounds of the Irminger Sea indicates a number of differences including spatial and vertical distribution, ambient temperature, length and age composition. Moreover, 12 morphometric and 4 meristic characters differed significantly between fish samples from these two areas. Results of Cluster Analysis showed the clear grouping of samples into that of the ‘oceanic’ component (depth 300–450 m) and the ‘deep sea’ component (depth 550–800 m). These results were confirmed by Principal Component Analysis, which revealed the separation of samples into two catch depth groups. The share of fish allocated by Discriminant Analysis into the pelagic ‘deep sea’ component in the northeastern area was nearly 92%, while the ‘oceanic’ component was dominant in the southwestern area and comprised more than 88% of the fish. Cluster and Principal Component analyses suggest that the ‘oceanic’ component is a more homogeneous group than the ‘deep sea’ component. These results support the management units recently established by ICES.     

Changes in plasma thiol levels induced by different phases of treatment in breast cancer; the role of commercial extract from black chokeberry

Different low-molecular-weight thiols, including glutathione, cysteine, and cysteinylglycine are physiological free radical scavengers. On the other hand, homocysteine may play a role as an oxidant. The aim of our present study was to establish in vitro the effects of the commercial extract of Aronia melanocarpa (Aronox^?) on the amount of selected low-molecular-weight thiols and the activity of antioxidative enzymes (superoxide dismutase, glutathione peroxidase, and glutathione reductase) in plasma obtained from patients with invasive breast cancer during different phases of treatment [before or after the surgery and patients after different phases of chemotherapy (doxorubicin and cyclophosphamide)] and from healthy subjects. Patients were hospitalized in Department of Oncological Surgery and Department of Chemotherapy, Medical University of Lodz, Poland. The level of low-molecular-weight thiols was determined by high-performance liquid chromatography. We observed that in the presence of the Aronia extract changes in amount of thiols in plasma from breast cancer patients (at all tested groups) were significantly reduced. Our results showed that tested commercial extract reduced modifications of antioxidative enzymes activity in plasma from patients during different phases of treatment, but this effect was not statistical significant. Our results suggest that the Aronia extract supplementation in breast cancer patients has a beneficial effect on thiols concentration in plasma. Plasma, as reported in this work, could be used as an experimental model to evaluate the beneficial action of plant supplements, including phenolic extracts on thiols or other molecules during different phases of treatment.     

Association of common WRAP 53 variant with ovarian cancer risk in the Polish population

Among many alterations within the TP53 gene the rs1042522 (C72G, p.Pro72Arg) has been associated with numerous cancers , however the results differ between populations for opposite Pro or Arg alleles. Similar thus inconclusive results are observed in ovarian cancer, which may suggest that the rs1042522 does not influence ovarian carcinogensis directly, but might be linked to another pathogenic alteration. WRAP53 which overlaps the TP53 is required to maintain normal levels of p53 upon DNA damage, but also when altered may independently increase the risk of cancer. To evaluate the association between three SNPs located in WRAP53–TP53 region: rs1042522, rs2287497, rs2287498 and ovarian cancer risk in Polish population we genotyped 626 cases and 1,045 healthy controls. Our results provide the evidence for an association between studied SNPs and a risk of invasive ovarian cancer in Poland. We found that CC homozygotes in rs1042522 were more frequent in cancers when compared to controls (OR = 1.46, p = 0.03). Similarly in WRAP53 both TT homozygotes in rs2287497 (OR = 1.95, p = 0.03) and AA homozygotes in rs2287498 (OR = 2.65, p = 0,01) were more frequent among cases than healthy individuals. There is also a suggestive evidence that specific homozygosity of studied SNPs in TP53–WRAP53 region is significantly overrepresented in ovarian cancer patients. In conclusion SNPs in WRAP53 (rs2287497 and rs2287498) have stronger association with an ovarian cancer risk than rs1042522 in TP53.