FTIR features of lithium-iron phosphates as electrode materials for rechargeable lithium batteries

The essential structural features of lithium-metal phosphates (LMP) have been studied using FTIR spectroscopy which is a sensitive tool to probe the local environment in the solid materials. Various LMP materials where M is iron have been investigated including phospho-olivine LiFePO(4), diphosphate LiFeP(2)O(7), Nasicon-type phosphate Li(3)Fe(2)(PO(4))(3) and dihydrate FePO(4).2H(2)O. Vitreous and amorphous materials are also considered. Analysis of internal and external modes of vibration allows to distinguish between the different phases and the type of cationic environment in the framework. Results corroborate the contribution of the main factors which are responsible for the complexity of the spectra, i.e. departure from ideal symmetry, interactions between polyhedra, bridging atoms and lattice distortion.

Hepatitis B virus genotypes in children with chronic hepatitis B in Poland

OBJECTIVES

To analyse the distribution of HBV genotypes in Polish children with chronic hepatitis B, and to assess the relation between the viral genotype and the severity of liver damage.

METHODS

Serum samples from children with chronic hepatitis B were used for biochemical and serological testing, and for determination of HBV genotypes by a nested-multiplex-polymerase chain reaction. Liver biopsies were obtained for histological assessment, which was performed according to the Batts and Ludwig scoring system of chronic hepatitis.

RESULTS

Of 78 children with chronic hepatitis B, 74 had an identifiable HBV genotype: 86.5% were infected with genotype A, and 13.5% were carriers of genotype D. The frequency of HBeAg clearance and the levels of alanine aminotransferase and serum aspartate transaminase were comparable in both genotype groups. There was no correlation between the HBV genotype and either activity of liver inflammation or liver fibrosis.

CONCLUSIONS

This study shows that the distribution of HBV genotypes in Polish children with chronic HBV infection reflects the general prevalence of HBV genotypes in Europe. The course of chronic hepatitis B in children is not significantly influenced by viral genotypes A or D.

Lack of an association between Helicobacter infection and autoimmune hepatitis in children

An association between Helicobacter infection and autoimmune hepatitis (AIH) in children was investigated. The prevalence of antibodies to H. pylori did not differ between the AIH and the control group, (22% versus 14%), and antibodies to non-gastric Helicobacter were not detected in either group. H. pylori DNA was found in two AIH liver tissues, but Helicobacter was not cultured from any sample.

Prevalence of potential virulence markers in Polish Campylobacter jejuni and Campylobacter coli isolates obtained from hospitalized children and from chicken carcasses

The pathogenicity of thermotolerant Campylobacter species, common food-borne pathogens, depends on certain factors unevenly distributed among strains of different origin. The prevalence of such markers has never been examined in a population of Polish Campylobacter strains of human and poultry origin. Therefore, we analysed the presence of the cadF, cdtA, cdtB and cdtC genes and the iam sequence in Campylobacter jejuni (n = 115) and Campylobacter coli (n = 57) isolates from children with diarrhoea and from chicken carcasses. The cadF gene was present in nearly 100% of Campylobacter isolates tested, regardless of their origin or species. In contrast, the iam region was found in 83.3% and 100% of C. coli isolates from children and chickens, respectively, but in only 1.6% and 54.7%, respectively, of C. jejuni isolates. Similarly, the detection rates of cdt genes varied between human and chicken isolates. All three cdt genes were found in nearly all C. jejuni isolates from both children and chickens, but in only 5.6% of human C. coli isolates as compared to 87.2% of chicken C. coli isolates. This different distribution of genetic markers between human and chicken isolates indicates that some Campylobacter infections in children may have additional sources other than contaminated chicken meat.

Antimicrobial resistance of Streptococcus pneumoniae and Haemophilus influenzae isolated from children with community-acquired respiratory tract infections in Central Poland

Resistance to commonly used antimicrobial agents among the key respiratory pathogens is increasing worldwide and therefore a rational choice of an empirical treatment requires knowledge of both global and local resistance patterns. The susceptibility of 185 Streptococcus pneumoniae and 169 Haemophilus influenzae isolates collected from January 1999 to May 2002 at the Children's Memorial Health Institute, Warsaw, Poland, from 351 children with community-acquired respiratory tract infections (RTIs) has been determined. Of S. pneumoniae isolates, 84% were susceptible to penicillin, 91% to cefaclor, 95% to cefuroxime, 98% to cefotaxime, 79% to erythromycin, 46% to co-trimoxazole, 82% to clindamycin and 59% to tetracycline. The majority (83%) of erythromycin-resistant isolates tested carried the erm(B) gene, conferring the MLS(B) phenotype. All tetracycline-resistant S. pneumoniae strains analysed were tet(M) positive and tet(O) negative. A total of 24% of H. influenzae isolates were beta-lactamase-positive. H. influenzae susceptibility to amoxicillin/clavulanate, cefaclor, cefuroxime, azithromycin, tetracycline and co-trimoxazole was 100, 89, 94, 96, 96 and 43%, respectively.