110 research outputs found
Multidrug-resistant Streptococcus pneumoniae in Poland: identification of emerging clones
Penicillin resistance among Streptococcus pneumoniae isolates has rapidly
emerged in Poland during the last decade and has reached prevalence levels
of up to 14.4% in 1997. In order to investigate the nature of this
increase, a molecular epidemiological analysis of
non-penicillin-susceptible multidrug-resistant pneumococci isolated in
1995 and 1996 was conducted. Thirty-seven patients who suffered mainly
from upper respiratory tract infections and pneumococcal pneumonia were
enrolled in this study. The medical centers to which the patients were
admitted were located in 16 Polish towns across the country. Eight
distinct BOX PCR types were observed, representing 14 subtypes.
Restriction fragment end labeling (RFEL) analysis divided the pneumococcal
strains into 16 distinct types. By combining the BOX PCR and RFEL data,
four genetically distinct clusters of strains were identified. Two
clusters represented the genetic clones 23F and 9V, which have recently
emerged all over the world. The two other genetic clusters, which
represented serotypes 23F and 6B, clearly predominated in the analyzed
collection of Polish non-penicillin-susceptible pneumococcal strains.
Since the latter clusters did not match any of the 133 RFEL types of
non-penicillin-susceptible pneumococci collected in 15 other countries,
their Polish clonal origin is most likely
Hydrogen peroxide in exhaled air is increased in stable asthmatic children
Exhaled air condensate provides a noninvasive means of obtaining samples
from the lower respiratory tract. Hydrogen peroxide (H2O2) in exhaled air
has been proposed as a marker of airway inflammation. We hypothesized that
in stable asthmatic children the H2O2 concentration in exhaled air
condensate may be elevated as a result of airway inflammation. In a
cross-sectional study, 66 allergic asthmatic children (of whom, 41 were
treated with inhaled steroids) and 21 healthy controls exhaled through a
cold trap. The resulting condensate was examined fluorimetrically for the
presence of H2O2. All subjects were clinically stable, nonsmokers, without
infection. The median H2O2 level in the exhaled air condensate of the
asthmatic patients was significantly higher than in healthy controls (0.60
and 0.15 micromol, respectively; p<0.05), largely because of high values
in the stable asthmatic children who did not use anti-inflammatory
treatment (0.8 micromol; p<0.01 compared to controls). We conclude that
hydrogen peroxide is elevated in exhaled air condensate of children with
stable asthma, and may reflect airway inflammation
Comparative Nationalism: Imperial Legacies and the Strength of Nationalism: The Case of China and India since the 1990s
Since the 1990s, there have been strong displays of nationalism in China, while in India the once dominant ‘secular’ nationalism has been challenged by a fragmentation of national identity along ethno--‐religious lines. This thesis seeks to explain why Chinese nationalism, since the 1990s, appears to be stronger and indeed more prevalent than nationalism in India. The phenomenon of nationalism in India and China has been extensively researched, yet there remains a deficiency in comparative research. Thereby, this thesis takes a historical Comparative approach through which five explanatory hypotheses are evaluated; these are entitled: direct rule, types of foreign rule, regime type, foreign threat, and diversity. The findings of this thesis suggest that China’s nationalism remains more prevalent since the 1990s, due to its experience of informal imperialism, a strong centralized Chinese state, and higher levels of militarized inter--‐state disputes. Simply, it is illustrated that because the experience of informal imperialism has centrally defined Chinese nationalism, it reacts Intensely to foreign threats that are equated to imperial acts, while the unified nature of nationalism is reinforced by a strong centralized state
MAGNETIC FORCES IN ORTHODONTICS
BACKGROUND: Pneumococcus is a major human pathogen and the polysaccharide capsule is considered its main virulence factor. Nevertheless, strains lacking a capsule, named non-typeable pneumococcus (NT), are maintained in nature and frequently colonise the human nasopharynx. Interest in these strains, not targeted by any of the currently available pneumococcal vaccines, has been rising as they seem to play an important role in the evolution of the species. Currently, there is a paucity of data regarding this group of pneumococci. Also, questions have been raised on whether they are true pneumococci. We aimed to obtain insights in the genetic content of NT and the mechanisms leading to non-typeability and to genetic diversity. RESULTS: A collection of 52 NT isolates representative of the lineages circulating in Portugal between 1997 and 2007, as determined by pulsed-field gel electrophoresis and multilocus sequence typing, was analysed. The capsular region was sequenced and comparative genomic hybridisation (CGH) using a microarray covering the genome of 10 pneumococcal strains was carried out. The presence of mobile elements was investigated as source of intraclonal variation. NT circulating in Portugal were found to have similar capsular regions, of cps type NCC2, i.e., having aliB-like ORF1 and aliB-like ORF2 genes. The core genome of NT was essentially similar to that of encapsulated strains. Also, competence genes and most virulence genes were present. The few virulence genes absent in all NT were the capsular genes, type-I and type-II pili, choline-binding protein A (cbpA/pspC), and pneumococcal surface protein A (pspA). Intraclonal variation could not be entirely explained by the presence of prophages and other mobile elements. CONCLUSIONS: NT circulating in Portugal are a homogeneous group belonging to cps type NCC2. Our observations support the theory that they are bona-fide pneumococcal isolates that do not express the capsule but are otherwise essentially similar to encapsulated pneumococci. Thus we propose that NT should be routinely identified and reported in surveillance studies
Molecular epidemiology of penicillin-nonsusceptible Streptococcus pneumoniae among children in Greece
A total of 145 penicillin-nonsusceptible Streptococcus pneumoniae strains
were isolated from young carriers in Greece and analyzed by antibiotic
susceptibility testing, serotyping, restriction fragment end labeling
(RFEL), and penicillin-binding protein (PBP) genotyping. The serotypes 23A
and 23F (54%), 19A and 19F (25%), 9V (5%), 15A, 15B, and 15C (4%), 6A and
6B (4%), and 21 (4%) were most prevalent in this collection. Fifty-three
distinct RFEL types were identified. Sixteen different RFEL clusters,
harboring 2 to 32 strains each, accounted for 82% of all strains. Eight of
these genetic clusters representing 60% of the strains were previously
identified in other countries. A predominant lineage of 66 strains (46%)
harboring five RFEL types and the serotypes 19F and 23F was closely
related to the pandemic clone Spain(23F)-1 (genetic relatedness of > or
=85%). Another lineage, representing 11 strains, showed close genetic
relatedness to the pandemic clone France(9V)-3. Another lineage of 8
serotype 21 strains was Greece specific since the RFEL types were not
observed in an international collection of 193 genotypes from 16 different
countries. Characterization of the PBP genes pbp1a, pbp2b, and pbp2x
revealed 20 distinct PBP genotypes of which PBP type 1-1-1, initially
observed in the pandemic clones 23F and 9V, was predominantly present in
11 RFEL types in this Greek collection of penicillin-nonsusceptible
strains (55%). Sixteen PBP types covering 52 strains (36%) were Greece
specific. This study underlines the strong contribution of
penicillin-resistant international clones to the prevalence and spread of
penicillin-nonsusceptible pneumococci among young children in Greece
Improving Urban Public Operation: Experience Of Rostov-On-Don (Russia)
This paper estimates experience of development of urban public transport in city Rostov-on- Don, Russia. The main aims of policy of municipal authorities on reforming public transport are analysed. The integrated decision of a problem included achievement of the following purposes: creation most appropriate structure of management of city public transport, change of form of ownership of public transport operators, improvement of competition on the entry of market of transport services, optimization of a routes network of public transport.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne
Hydrogen peroxide in exhaled air of healthy children: reference values
An increased content of hydrogen peroxide (H2O2), a marker of
inflammation, has been described in the condensate of exhaled air from
adults and children with inflammatory lung disorders, including asthma.
However, the normal range of [H2O2] in the exhaled air condensate from
healthy children has not been established. Therefore, the aim of this
study was to determine the reference range of exhaled [H2O2] in healthy
school-aged children. Ninety-three healthy nonsmoking children (48 female
and 45 male, mean age 10 yrs, range 8-13 yrs), with a negative history for
allergy, eczema or respiratory disease and with a normal lung function,
participated. Exhaled air condensate was examined fluorimetrically for the
presence of H2O2. In addition, the reproducibility of [H2O2] within
subjects and between days and the stability of [H2O2] during storage at
-20 degrees C were assessed. The median [H2O2] in the exhaled air
condensate of all children was 0.13 microM, with a 2.5-97.5% reference
range of <0.01-0.48 microM. No significant difference existed between
males and females. There was no correlation between exhaled [H2O2] and age
or lung function. Repeated [H2O2] measurements on 2 consecutive days
showed satisfactory within-subject reproducibility and [H2O2] in stored
samples remained stable for at least 1 month at -20 degrees C. In
conclusion, this study provides reference data for exhaled hydrogen
peroxide in a large group of healthy children. The observed levels were
lower than those reported previously for healthy adults and were
independent of age, sex and lung function
Molecular typing of Salmonella typhi strains from Dhaka (Bangladesh) and development of DNA probes identifying plasmid-encoded multidrug-resistant isolates
Seventy-eight Salmonella typhi strains isolated in 1994 and 1995 from
patients living in Dhaka, Bangladesh, were subjected to phage typing,
ribotyping, IS200 fingerprinting, and PCR fingerprinting. The collection
displayed a high degree of genetic homogeneity, because restricted numbers
of phage types and DNA fingerprints were observed. A significant number of
the S. typhi strains (67%) were demonstrated to be multiple drug resistant
(MDR). The vast majority of the MDR strains were resistant to
chloramphenicol, ampicillin, trimethoprim, streptomycin, sulfamethoxazole,
and tetracycline (R type CATmSSuT), a resistance phenotype that has also
frequently been observed in India. Only two strains displayed a distinct
MDR phenotype, R type AT-mSSuT. Pulsed-field gel electrophoresis
demonstrated the presence of large plasmids exclusively in the MDR strains
of both R types. The plasmids present in the S. typhi strains of R type
CATmSSuT could be conjugated to Escherichia coli and resulted in the
complete transfer of the MDR phenotype. PCR fingerprinting allowed
discrimination of MDR and susceptible strains. The DNA fragments enabling
discrimination of MDR and susceptible S. typhi strains by PCR were useful
genetic markers for identifying MDR encoded by large plasmids of the H1
incompatibility group
The putative proteinase maturation protein A of Streptococcus pneumoniae is a conserved surface protein with potential to elicit protective immune responses
Surface-exposed proteins often play an important role in the interaction
between pathogenic bacteria and their host. We isolated a pool of
hydrophobic, surface-associated proteins of Streptococcus pneumoniae. The
opsonophagocytic activity of hyperimmune serum raised against this protein
fraction was high and species specific. Moreover, the opsonophagocytic
activity was independent of the capsular type and chromosomal genotype of
the pneumococcus. Since the opsonophagocytic activity is presumed to
correlate with in vivo protection, these data indicate that the protein
fraction has the potential to elicit species-specific immune protection
with cross-protection against various pneumococcal strains. Individual
proteins in the extract were purified by two-dimensional gel
electrophoresis. Antibodies raised against three distinct proteins
contributed to the opsonophagocytic activity of the serum. The proteins
were identified by mass spectrometry and N-terminal amino acid sequencing.
Two proteins were the previously characterized pneumococcal surface
protein A and oligopeptide-binding lipoprotein AmiA. The third protein was
the recently identified putative proteinase maturation protein A (PpmA),
which showed homology to members of the family of peptidyl-prolyl
cis/trans isomerases. Immunoelectron microscopy demonstrated that PpmA was
associated with the pneumococcal surface. In addition, PpmA was shown to
elicit species-specific opsonophagocytic antibodies that were
cross-reactive with various pneumococcal strains. This antibody
cross-reactivity was in line with the limited sequence variation of ppmA.
The importance of PpmA in pneumococcal pathogenesis was demonstrated in a
mouse pneumonia model. Pneumococcal ppmA-deficient mutants showed reduced
virulence. The properties of PpmA reported here indicate its potential for
inclusion in multicomponent protein vaccines
Bacterial lipopolysaccharide inhibits influenza virus infection of human macrophages and the consequent induction of CD8+ T cell immunity
Item does not contain fulltextIt is well established that infection with influenza A virus (IAV) facilitates secondary bacterial disease. However, there is a growing body of evidence that the microbial context in which IAV infection occurs can affect both innate and adaptive responses to the virus. To date, these studies have been restricted to murine models of disease and the relevance of these findings in primary human cells remains to be elucidated. Here, we show that pre-stimulation of primary human monocyte-derived macrophages (MDMs) with the bacterial ligand lipopolysaccharide (LPS) reduces the ability of IAV to infect these cells. The inhibition of IAV infection was associated with a reduced transcription of viral RNA and the ability of LPS to induce an anti-viral/type I interferon response in human MDMs. We demonstrated that this reduced rate of viral infection is associated with a reduced ability to present a model antigen to autologous CD8+ T cells. Taken together, these data provide the first evidence that exposure to bacterial ligands like LPS can play an important role in modulating the immune response of primary human immune cells towards IAV infection, which may then have important consequences for the development of the host's adaptive immune response
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