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The electronic structures of bis(tert-butylimino)bis(dimethylamino) tungsten and bis(N-ethylethanaminato)bis(N-methylmethanaminato) titanium heteroleptic complexes, which are precursors for atomic layer deposition of metallic nitride on surfaces, have been investigated by HeI and HeII UV photoelectron spectroscopy and DFT/OVGF calculations. We discuss the electronic structures of these two and other related d(0)-type complexes in relation to the mechanism of adsorption and decomposition of metal alkylamide precursors on surfaces.

Spontaneous sauerkraut fermentation was performed at industrial scale in "Prehrana Inc.", Varaždin, in order to select autochthonous lactic acid bacteria (LAB) which were evaluated according probiotic criteria and tested for their capacity as probiotic starter cultures. At the end of the spontaneous sauerkraut fermentation, total LAB counts reached 9.0×10(5) CFU/ml. This underlines that the need for addition of the well characterised probiotic cultures, in appropriate viable cell counts, would be valuable in probiotic sauerkraut production. Phenotypic characterisation through API 50 CHL and SDS-PAGE of cell protein patterns revealed that Lactobacillus plantarum is predominant LAB strain in homofermentative phase of fermentation. Autochthonous LAB isolates SF1, SF2, SF4, SF9 and SF15 were selected based on the survival in in vitro gastrointestinal tract conditions. RAPD fingerprints indicated that the selected autochthonous LAB were distinct from one another. All of the strains efficiently inhibited the growth of indicator strains and satisfied technological properties such as acidification rate, tolerance to NaCl and viability during freeze-drying. Strains Lb. paraplantarum SF9 and Lb. brevis SF15, identified by AFLP DNA fingerprints, have shown the best properties to be applied as probiotic starter cultures, because of their highest adhesion to Caco-2 cells and expression of specific, protective S-layer proteins of 45 kDa in size. With addition of these strains, probiotic attribute of the sauerkraut will be achieved, including health promoting, nutritional, technological and economic advantages in large scale industrial sauerkraut production., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Electron paramagnetic resonance (EPR) signals induced by γ-radiation in different polymorphic forms of trehalose were studied with dosimetry applications in view. Dose response of trehalose in terms of the concentration of induced paramagnetic centers was studied in the dose range from 0.5 to 50 kGy. The dependences of the dose responses of anhydrous β-crystalline trehalose (TRE(β)) and glassy trehalose (TRE(g)) on dose are linear up to 15 kGy, whereas the linearity of the dependence for trehalose dihydrate (TRE(h)) is limited to about 10 kGy. At doses above 15 kGy, the dependences get saturated for all three forms. The relative radiation sensitivities pointed to the following order of decreasing concentrations of radiation-induced paramagnetic centers in the forms: TRE(g)>TRE(β)>TRE(h). The results showed that at all three trehalose polymorphic forms are suitable for dosimetry, especially for retrospective dose measurements. Also, thermal stability and decay kinetics of the EPR signals of the different forms of trehalose were studied in isothermal annealing experiments. The kinetic parameters, which had been derived by fitting the Arrhenius function to the measured decay rate constants, indicated that the fading of the EPR signals varied from one polymorphic form of trehalose to another. This emphasizes the impact of the molecular packing in the vicinity of the radiation-induced paramagnetic centers on their stability., (© 2013 Elsevier Ltd. All rights reserved.)

Electron spin-lattice relaxation (SLR) of TEMPO radical was measured in the crystalline and glassy states of deuterated ethanol in the temperature range 5-80K using X-band electron paramagnetic resonance (EPR). The measured SLR rates are higher in the glassy than in crystalline state and the excess SLR rate in glassy state is much lower than in ethanol. This result suggests that extra modes in glassy state, i.e. glassy modes, produce the excess SLR rate via the electron-nuclear dipolar (END) interaction between the electron spin of radical and the matrix protons or deuterons. Using the soft-potential model and assuming the END interaction between the electron spin and the matrix protons, the contributions to SLR rate of various mechanisms of glassy modes were theoretically analyzed. The evaluations of SLR rates in glassy ethanol indicate two main mechanisms of glassy modes: thermally activated relaxation of double-well systems and phonon-induced relaxation of quasi-harmonic local modes. The SLR rates induced by these mechanisms correlate well with the experimental data., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Cerebral palsy (CP) is a nonprogressive motor disorder caused by white matter damage in the developing brain and is often accompanied with cognitive and sensory disabilities. The risk of CP is higher among infants born preterm than in more mature infants. Intrauterine infection/inflammation, activation of the cytokine network and elevated levels of proinflammatory cytokines in neonatal blood or in amniotic fluid to which the preterm infant is exposed, has been identified as the most common cause of preterm delivery, periventricular leukomalacia (PVL) and CP. The aim of our study was to evaluate the possible association of four TNFα promoter single nucleotide polymorphisms (SNPs) (-1031 T/C, -857 C/T, -308 G/A and -238 G/A), two IL1β SNPs (-511 C/T and +3954 C/T) and one IL6 (-174 C/G) polymorphism with susceptibility to CP in very preterm infants. Statistically significant association between TNFα -1031 T/C high expression genotypes (TC and CC) (OR, 2.339; p=0.016) as well as between TNFα -1031 C high expression allele (OR, 2.065; p=0.013) and risk of CP was observed. In addition, statistically significant association was found between TNFα TC, CC, GG, GG -1031/-857/-308/-238 genotypes combination (OR, 3.286; p=0.034) and risk of CP. Statistically significant association between IL1β TT, CC -511/+3954 genotypes combination and risk of CP (OR, 4.000; p=0.027) was also found. In CP patients with cystic PVL (cPVL) statistically significant association was found between TNFα -1031 T/C high expression genotypes (TC and CC) (OR, 2.361; p=0.038), IL1β -511 C/T high expression genotype TT (OR, 3.215; p=0.030) as well as IL1β -511 T high expression allele (OR, 1.956; p=0.019) and risk of CP. Statistically significant association was also found in patients with cPVL between TNFα TC, CC, GG, GG -1031/-857/-308/-238 genotypes combination (OR, 4.107; p=0.024), as well as IL1β TT, CC -511/+3954 genotypes combination (OR, 7.333; p=0.005) and risk of CP. Our results suggest the role of TNFα and IL1β polymorphisms which have previously been associated with higher circulating levels of these cytokines in genetic susceptibility to white matter damage and consequently CP in very preterm infants., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Altered folate levels may play an important role in colon carcinogenesis. The aim of this study was to investigate the association of polymorphisms in key folate-metabolizing genes with susceptibility to sporadic colon cancer. Six common polymorphisms (two in MTHFR and one each in MTR, MTRR, RFC1, and DHFR genes) were genotyped in 300 healthy subjects and 300 colon cancer patients from Croatia. Obtained results indicate possible protective role of MTRR 66 AA in sporadic colon cancer (OR=0.655; 95% CI=0.441-0.973; p=0.04). Maximum-likelihood analysis of haplotypes revealed a linkage disequilibrium (LD) between the two investigated polymorphisms of the MTHFR gene (C677T and A1298C), both in the control and patient groups (p<0.01 for both). LD was also detected between MTRR A66G and MTHFR A1298C polymorphisms but only in a group of patients (p<0.01). A haplotype of A66G and A1298C polymorphisms, A/A, proved to be protective (OR=0.775; 95% CI=0.603-0.996; p=0.04), whereas haplotype A/G was a risk factor for colon cancer (OR=1.270; 95% CI=1.007-1.602; p=0.04). Contrary to some previous studies, single-locus analyses identified no polymorphisms associated with risk for colon cancer, but demonstrated a possible protective effect of MTRR 66 AA genotype. The detected significant LD between two loci (MTHFR A1298C and MTRR A66G) located on different chromosomes indicates a strong selective force as a mechanism for the maintenance of their linkage. Specific combinations of alleles of these two polymorphisms showed a protective but also a risk effect on colon cancer susceptibility.

We have investigated the electron phase-memory relaxation time of the nitroxyl radical 2,2,6,6-tetramethylpiperidine-1-oxyl at temperatures between 5 and 80 K in crystalline and glassy states of ethanol using pulsed X-band electron paramagnetic resonance spectroscopy. The results indicate that the transition from the slow to fast motion regimes of the paramagnetic center occurs upon further cooling of the sample below ∼20 K. We provide experimental evidence that this phenomenon cannot be ascribed to the impact of hyperfine interactions with methyl protons in the system, but it can be instead a signature of the coupling of the electron spin with the boson peak excitations of the lattice.

In this work we report on gelation properties, self-assembly motifs, chirality effects and morphological characteristics of gels formed by chiral retro-dipeptidic gelators in the form of terminal diacids (1a-5a) and their dimethyl ester (1b-5b) and dicarboxamide (1c-5c) derivatives. Terminal free acid retro-dipeptides (S,S)-bis(LeuLeu) 1a, (S,S)-bis(PhgPhg) 3a and (S,S)-bis(PhePhe) 5a showed moderate to excellent gelation of highly polar water/DMSO and water/DMF solvent mixtures. Retro-peptides incorporating different amino acids (S,S)-(LeuPhg) 2a and (S,S)-(PhgLeu) 4a showed no or very weak gelation. Different gelation effectiveness was found for racemic and single enantiomer gelators. The heterochiral (S,R)-1c diastereoisomer is capable of immobilizing up to 10 and 4 times larger volumes of dichloromethane/DMSO and toluene/DMSO solvent mixtures compared to homochiral (S,S)-1c. Based on the results of (1)H NMR, FTIR, CD investigations, molecular modeling and XRPD studies of diasteroisomeric diesters (S,S)-1b/(S,R)-1b and diacids (S,S)-1b/(S,R)-1a, a basic packing model in their gel aggregates is proposed. The intermolecular hydrogen bonding between extended gelator molecules utilizing both, the oxalamide and peptidic units and layered organization were identified as the most likely motifs appearing in the gel aggregates. Molecular modeling studies of (S,S)-1a/(S,R)-1a and (S,S)-1b/(S,R)-1b diasteroisomeric pairs revealed a decisive stereochemical influence yielding distinctly different low energy conformations: those of (S,R)-diastereoisomers with lipophilic i-Bu groups and polar carboxylic acid or ester groups located on the opposite sides of the oxalamide plane resembling bola amphiphilic structures and those of (S,S)-diasteroisomers possessing the same groups located at both sides of the oxalamide plane. Such conformational characteristics were found to strongly influence both, gelator effectiveness and morphological characteristics of gel aggregates.

Cytokines participate in tumorigenesis of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Single nucleotide polymorphisms (SNPs) in cytokine genes influence expression of proteins and are evaluated in cancer susceptibility. The aim of this study was to evaluate IL-2 -330 T/G SNP and susceptibility to GEP-NETs, and analyze the correlation between G-allele and IL-2 serum values in GEP-NET patients. Moreover we assessed the value of IL-2 as a tumor serum marker. IL-2 -330 T/G SNP was examined in 101 patients and 150 healthy volunteers and IL-2 serum levels in patients and 20 controls. Patients' IL-2 serum levels were compared to IL-2 -330 T/G genotypes and tumor functional status and finally with known markers such as chromogranin A (CgA) and 5-hydroxyindolacetic acid (5-HIAA). There was a significant difference in genotype distribution of the IL-2 -330 polymorphisms between GEP-NET and control group (p = 0.0006) as well as in the frequency of G-allele (p = 0.010). G-allele correlated with higher IL-2 serum levels (p = 0.028) and elevated in all patients, being highest in patients with functional tumors (p = 0.039). Compared to CgA and 5-HIAA, IL-2 was more specific in detecting GEP-NET patients (p < 0.0001 and p < 0.0001, respectively). Our results indicate importance of IL-2 in GEP-NET development and biochemical diagnosis.

Interleukin-6 (IL-6) has been implicated in tumorigenesis; however, its role is still far from being clearly defined. Regulation of IL-6 expression is highly complex, and additional complexity is introduced by single-nucleotide polymorphisms in the IL-6 gene. These single-nucleotide polymorphisms might influence mRNA transcription, which might in turn result in increased susceptibility to certain tumors. The aim of this study was to analyze IL-6 mRNA and protein expressions in sporadic colon cancer. Influence of IL-6-174 G/C polymorphism on IL-6 mRNA expression and sporadic colon cancer susceptibility was evaluated as well. The frequency of IL-6-174 G/C was analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis. IL-6 mRNA and protein expressions were analyzed by real-time reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. No statistically significant difference in IL-6 mRNA expression in tumor tissue compared with the corresponding normal tissue was observed (p = 0.116). No correlation was found between IL-6 mRNA and protein expressions and clinicopathological features of sporadic colon tumors. There was no association of IL-6-174 G/C genotypes with IL-6 mRNA expression in colon tumors and corresponding normal mucous tissue (p = 0.355; p = 0.152). Finally, there was no association of IL-6-174 G/C with susceptibility to sporadic colon cancer.

In this case-control study the association between the PTPN22 1858T and CTLA-4 49G gene variants and T1D in Croatian population was examined. We found that distribution of PTPN22 C1858T and CTLA-4 A49G genotypes between T1D patient (n=102) and control (n=193) groups differ significantly (p<0.0001 and p=0.012, respectively). Moreover, although the risk alleles of both SNPs are distributed more frequently in patients, the significant difference is observed only for PTPN22 1858T allele (p<0.0001). This is therefore the first evidence that analyzed gene variants contribute to T1D pathogenesis in Croatian population.

Aneurysms on cerebral blood vessels due to their localization, size, relationship with neurovascular structures, even today, represent besides the constant progress of the diagnostic techniques and instruments in the operating theaters, a great therapeutic challenge. Gigantic aneurysms, aneurysms localized within the cavernous sinus and aneurysms of the vertebrobasilary confluence carry a great perioperative risk of mortality and morbidity. In fact, development of the endovascular procedures for the occlusion of their lumen made possible great progress in the treatment of aneurysms of this localization. In a not so small number of cases endovascular procedure means remodeling of the lumen of the main blood vessel. Endovascular obliteration of aneurysms has a certain advantage as regards the surgical treatment of aneurysms in which, on the basis of the expected natural course and presumed operative risk, may be judged that there exists unacceptably great operative risk. We present a personal series and results in 6 patients with aneurysms of various localizations.

IL-6 is a pleiotropic cytokine with still controversial role in tumorigenesis of different cancer types. Its promoter SNP-174 C/G is associated with increased IL-6 transcription and in some tumor types with elevated IL-6 serum levels. The role of IL-6 polymorphisms and IL-6 serum values and their correlation in the gastroenteropancreatic neuroendocrine tumors is lacking. We investigated for the first time frequencies of IL-6-174 genotypes in 80 GEP-NET patients and 162 age- and sex-matched healthy controls, serum values of IL-6 in GEP-NET patients and their correlation with IL-6-174 genotypes. To analyze IL6-174 C/G polymorphism PCR-NlaIII RFLP method was used, and serum levels were measured on Immulite analyzer by enzymatic solid-phase chemiluminescent immunometric method. Serum IL-6 values were elevated (>5.9 pg/ml) in 36.8% GEP-NET patients. Differences in genotypes distribution between patients and healthy controls as well as between patients with gastrointestinal and pancreatic neuroendocrine tumors (PETs) and functioning and nonfunctioning PETs were tested by chi(2) test and Fisher's Exact test. Analysis of variance (ANOVA with proc GLM in SAS/Stat) was performed for the group comparison. Level of significance was alpha=0.05. Patients with nonfunctioning PETs had only high expression IL-6-174 CG and GG genotypes and according to genotypes differed significantly (p=0.0289) from functioning PETs. High serum IL-6 values in all GEP-NET patients correlated significantly with GG IL-6-174 genotype (p=0.0139). Nonfunctioning PET patients had significantly (p=0.000777) higher IL-6 serum values in comparison to patients with functioning PETs and gastrointestinal NETs. Serum IL-6 values correlated significantly with IL-6-174 genotypes in nonfunctioning PETs and gastrointestinal NETs (p<0.05), but not in functioning PETs.

Purpose: Colon cancer is a genetic disease, caused by mutations in different oncogenes and tumor-suppressor genes. The aim of this study is to evaluate the usefulness of real-time PCR SNP analysis as a new technique in the loss of heterozygosity (LOH) analysis at the E-cadherin gene locus in sporadic colon cancer., Methods: One-hundred cases of human sporadic colon cancer and corresponding normal tissue samples were analyzed using two flanking polymorphic markers commonly used in the LOH analysis at the E-cadherin gene locus by conventional VNTR-LOH analysis. Two intragenic E-cadherin SNP markers were analyzed using real-time PCR SNP analysis., Results: LOH (17.6%) was detected using flanking markers, however, no LOH was detected when the intragenic E-cadherin SNP markers were introduced into our study. Since these markers are intragenic they more accurately represent the status of the E-cadherin gene than the previously used flanking markers., Conclusion: In conclusion, real-time PCR SNP analysis was found to be more accurate, faster, simpler, and a more high-throughput method than the conventional VNTR-LOH analysis.

Introduction: Vitiligo is an acquired, sometimes familial skin depigmentation disorder. In about half of patients it occurs before the age of twenty. The aim of this study was to investigate the incidence and significance of autoantibodies (AT) and associated autoimmune and endocrine diseases in children with vitiligo, in relation to adults with vitiligo and children without vitiligo., Material and Methods: The research was conducted in fifty children with clinically diagnosed vitiligo from 2 to 16 years of age. Children were compared with control groups of children with other skin diseases (aged from 2 to 16) and with adults with vitiligo. Each group comprised 30 patients. A detailed history was obtained and physical examination was performed in each patient to determine presence of autoimmune and endocrine diseases in patients with family history of vitiligo. Routine blood examination, routine urinalysis and stool were performed in all patients. We evaluated the incidence of antinuclear (ANA) and antithyroid antibodies (ATA) in each patient, as well as the incidence of antibodies to gastric parietal cell (APCA), smooth muscle (SMA), cord (ACA) and mitochondrial antigens (AMA) in 38 children with vitiligo and in control groups., Results: Children with vitiligo had positive family history of vitiligo more often compared to children without vitiligo (p<.05). Presence of ANA, ATA, APCA, SMA, ACA and AMA was not considerably increased in children with vitiligo compared with their age group. ANA was more common in adults with vitiligo, in comparison with children with vitiligo (p<0.05). None of the children with vitiligo had an associated autoimmune and endocrine disease in contrast to adults with vitiligo (p<0.05)., Discussion and Conclusion: Several studies have shown a significant incidence of positive autoantibodies in children with vitiligo, compared to children without vitiligo. However, in our series, presence of ANA, ATA, APCA, SMA, ACA and AMA was not significantly increased in children with vitiligo, compared with children without vitiligo. Further studies are necessary in this area in order to draw more conclusions. In the previous studies, it has been established that children with vitiligo were generally healthy, whereas adults with vitiligo had an increased incidence of autoimmune and/or endocrine diseases. No studies have shown this association in children with vitiligo. Our results support findings of previous studies.

To compare the structural properties of oxalamide and thiooxalamide groups in the formation of hydrogen bonds suitable for supramolecular assemblies a series of retropeptides was studied. Some of them, having oxalamide bridges, are gelators of organic solvents and water. However, retropeptides with oxygen replaced by the sp(2) sulfur have not exhibited such properties. The crystal structures of the two title compounds are homostructural, i.e. they have similar packing arrangements. The monothio compound crystallizes in the orthorhombic space group P2(1)2(1)2(1) with two molecules in the asymmetric unit arranged in a hydrogen-bond network with an approximate 4(1) axis along the crystallographic b axis. However, the dithio and dioxo analogues crystallize in the tetragonal space group P4(1) with similar packing patterns and hydrogen-bonding systems arranged in agreement with a crystallographic 4(1) axis. Thus, these two analogues are isostructural having closely related hydrogen-bonding patterns in spite of the different size and polarity of oxygen and sulfur which serve as the proton acceptors.

Four new chiral bis(amino alcohol)oxalamides (1-4: amino alcohol=leucinol, valinol, phenylglycinol, and phenylalaninol, respectively) have been prepared as low-molecular-weight organic gelators. Their gelation properties towards various organic solvents and mixtures were determined and these were then compared to related bis(amino acid) oxalamide gelators. Spectroscopic (FTIR, (1)H NMR) and X-ray diffraction studies revealed that the primary organization motif of (S,S)-1 and racemate 1 (rac-1) in lipophilic solvents involved the formation of inverse bilayers. The X-ray crystal structure of (S,S)-1 also shows this type of bilayer organization. The crystal structure of rac-2 reveals meso bilayers of hydrogen-bonded aggregates. Within the bilayers formed, the gelator molecules are connected by cooperative hydrogen bonding between oxalamide units and OH groups, while the interbilayer interactions are realized through lipophilic interactions between the iBu groups of leucinol. Oxalamide meso-1 lacks any gelation ability and crystallizes in monolayers. In dichloromethane rac-1 forms an unstable gel; this is prone to crystallization as a result of the formation of symmetrical meso bilayers. In contrast, in aromatic solvents rac-1 forms stable gels; this indicates that enantiomeric bilayers are formed. Oxalamide rac-1 is capable of gelling a volume of toluene three times larger than (S,S)-1. A tranmission electron microscopy investigation of rac-1 and (S,S)-1 toluene gels reveals the presence of thinner fibers in the former gel, and, hence, a more compact network that is capable of immobilizing a larger volume of the solvent. The self-assembly of these types of gelator molecules into bilayers and subsequent formation of fibrous aggregates can be explained by considering the strength and direction of aggregate forces (supramolecular vectors) in three-dimensional space.

Some bis (amino acid) oxalamide gelators form common thermo-reversible gels with various organic solvents but also gels of exceptional thermal stability with some solvents of medium and low polarity; the latter gels can be heated up to 50 degrees C higher temperatures than the bp of the solvent without apparent gel-to-sol transition.

The photoinduced gelation system based on 1 (non-gelling) to 2 (gelling) molecular photoisomerization in water results by microspheres (1) to gel fibers (2) transformation at the supramolecular level.

The molecule of benzene-1,4-dicarboxamidine or benzdiamidine, C(8)H(10)N(4), reveals C(i) symmetry. Hydrogen bonds utilize the amino groups as double donors, whereas the imino groups act as double acceptors. The network formed is similar to that observed in the crystal packing of terephthalamide.

Bis(LeuOH) (1a), bis-(ValOH) (2a) and bis(PhgOH) (5a) (Phg denotes (R)-phenylglycine) oxalyl amides are efficient low molecular weight organic gelators of various organic solvents and their mixtures as well as water, water/DMSO, and water/DMF mixtures. The organisational motifs in aqueous gels are dominated primarily by lipophilic interactions while those in organic solvents are formed by intermolecular hydrogen bonding. Most of the gels are thermoreversible and stable for many months. However, 2a forms unstable gels with organic solvents which upon ageing transform into variety of crystalline shapes. For some 1a/alcohol gels, a linear correlation between alcohol dielectric constants (epsilon) and gel melting temperatures (Tg) was found. The 1H NMR and FTIR spectroscopic investigations of selected gels reveal the existence of temperature dependent network assembly/dissolution equilibrium. In the 1H NMR spectra of gels only the molecules dissolved in entrapped solvent could be observed. By using an internal standard, the concentration of dissolved gelator molecules could be determined. In FTIR spectra, the bands corresponding to network assembled and dissolved gelator molecules are simultaneously present. This enabled determination of the Kgel values by using both methods. From the plots of InKgel versus 1/T, the deltaHgel values of selected gels have been determined (-deltaHgel in 10-36 kJ mol(-1) range) and found to be strongly solvent dependent. The deltaHgel values determined by 1H NMR and FTIR spectroscopy are in excellent agreement. Crystal structures of 2a and rac-5a show the presence of organisational motifs and intermolecular interactions in agreement with those in gel fibres elucidated by spectroscopic methods.

In the title compound, C20H22N4O4*C2H6OS, two distinct hydrogen-bond systems connect oxalamide groups in one pattern and primary amide groups in the other to form a two-dimensional network perpendicular to the c axis. These hydrophilic layers are joined to the three-dimensional structure through C--H...pi interactions. The hydrogen-bonded waved layers shape holes which are occupied by disordered dimethyl sulfoxide solvent molecules.

The title compound, 2,2'-(oxalyldiimino)bis(3-methylbutanoic acid), C12H20N2O6, possesses a centre of symmetry. In the crystal, molecules are connected by hydrogen bonds between oxamide and carboxyl groups, similar to the pattern of the monoclinic forms of HO-Gly-CO-CO-Gly-OH and HO-Aib-CO-CO-Aib-OH (Gly is glycine and Aib is 2-aminoisobutyric acid). The characteristic torsion angles in the title compound are close to those in peptide alpha-helices.

Novel pyrimido[1,2-a]pyrimidinones 14, 15 and 16 and imidazo[1,2-a] pyrimidinones 19 and 20, designed as conformationally constrained analogues of 1-(3-amino-2-hydroxypropyl)thymine and 1-(2-amino-3-hydroxypropyl)thymine, respective ly, were synthesized by the ring-opening/ ring-closure rearrangement of the corresponding byciclic oxygen-containing amino compounds 12 and 17.

Because of a growing need for the selection, flow of information, and adequate application of scientific information, the presentation of the utilization of databases and their information sources is necessary. An outline of databases and the description of structure and contents of the most important databases are given. The databases are chosen according to the scope of the field they cover in order to supply users with the best possible information in the field of biomedicine. The following databases are included: Biosis Previews, Ca Search, Cancerlit, Clinical Abstracts, Consumer Drug Information Fulltext, De Haen Drug Data, Diogenes, Drug Information Fulltext, Embase, Health Planning & Administration, International Pharmaceutical Abstracts, Life Sciences Collection, Martindale Online, Medline, Mental Health Abstracts, Nursing & Allied Health, Occupational Safety and Health, Pharmaceutical News Index and Smoking and Health.

The diastereoisomeric differentiations and anomerizations of 5,6-dihydrothymidine and its anhydro derivatives were studied. In particular, the oxetane ring opening of (5S)-1-(3,5-anhydro-2-deoxy-beta-D-threopentofuranosyl)-5,6-dihydr othymine under acid catalysed conditions substantiated a number of the configurational modifications at the sugar moiety. The 1,3-dipolar cycloaddition to the pyrimidine C(5), C(6)-double bond was intramolecularly facilitated by the activation of 1-(3-azido-2-hydroxypropyl)uracil. (E)- and (Z)-1-Prop-enyl- and properly functionalized 1-propyl-uracil derivatives were also prepared and used for the synthesis of the tetrahydro-oxazolo[3,2-c]pyrimidine-5,6-(4H, 6H)dione and 9,3'-cyclo-3-propyl (or prop-1-enyl)-8-azaxanthine derivatives.