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PubMed1976

[Leptospirosis in a Dakar hospital: results of a new survey].

The incidence of leptospirosis in West Africa is still almost unknown. Doubtful or positive serological tests were found in approx. 35% of the patients admitted to the hospital, among which leptospirosis could clinically or biologically be suspected. This rather high proportion reflects the frequency of recent or past contacts with leptospira antigen. It is in agreement with the high infestation prevalence observed among several domestic or wild animals, besides small rodents. On the countrary, it should be noted that the leptospirosis-illness, at least in its pure form, with its characteristic hepatic, renal and neurological signs, is seldom seen. Seven typical cases only (among which five at the hosptical Le Dantec) have been diagnosed in Dakar during these last 6 years. Even taking into account that the proportion of atypical, fruste or undiagnosed forms is not negligible, leptospirosis does not appear to be a major medical problem in Senegal.

Adult↗

PubMed1977

[Chemotherapy of microbial diseases of the respiratory tract].

It is given a survey on the chemotherapy of the microbial diseases of the respiration tract. A chemotherapy is taken into consideration only for such cases in which a bacterial etiology is ascertained or is assumed with a great probability. The antimicrobial chemotherapy is of particular importance for the acute and chronic bronchitis, bronchiectases, pneumonias, pulmonary abscess and empyema of the pleura. The author deals with the special problems of bacteriological findings of the respiratory tract. The choice of the chemotherapeutic remedy is done in most cases according to the empirical points of view, in which cases development of resistance, side-effects and changing of the infection must be taken into consideration. Apart from the otherwise usual oral and parenteral application special forms of application, such as aerosol therapy and intrapleural instillation are used. It is referred to atypical pneumonias, such as the mycoplasma pneumonia which gives a good response to tetracyclines. Apart from the sulphonamides and trimethoprim penicillins, chloramphenicol, tetracyclines, cephalosporines, more rarely streptomycin and linkomycin are the most important antimicrobiotics.

Anti-Bacterial Agents↗

PubMed2004

Reevaluating gel-forming mucins' roles in cystic fibrosis lung disease.

The existence of mucus plugs, containing mucins, bacteria, and neutrophils, blocking the lower airways in the lung of cystic fibrosis (CF) patients has raised the possibility that production of "abnormal" mucins is a critical characteristic of this disease. The molecular nature, if any, of this abnormality is unknown. Recent studies suggest that CF lung disease progression is characterized by an early phase in which airway surface liquid (ASL) increased dehydration is accompanied by altered pH and levels of reduced glutathione (GSH). In a later phase, bacterial infection and neutrophil invasion lead to increased ASL of concentrations myeloperoxidase and hypochlorous acid (HOCl). Independent studies indicate that gel-forming mucins, the key components of airway mucus, form disulfide-linked polymers through a pH-dependent, likely self-catalyzed mechanism. In this article, we present the hypothesis that increased mucus concentration (dehydration) and altered pH, and levels of GSH, myeloperoxidase, and/or HOCl result in the extracellular formation of additional interchain bonds among airway mucins. These novel interactions would create an atypical mucin network with abnormal viscoelastic and adhesive properties.

Bacterial Infections↗

PubMed1994

Characteristics of 'atypical', cytochrome oxidase-negative Aeromonas salmonicida isolated from ulcerated flounders (Platichthys flesus (L.)).

'Atypical', cytochrome oxidase-negative variants of the fish pathogen Aeromonas salmonicida, isolated from ulcerated flounder (Platichthys flesus), were studied using different methods. Two of the strains possessed a protein that corresponded to the A-layer protein of Aer. salmonicida. The strains reacted with antibodies against the A-layer and monoclonal antibodies against the O-antigen of typical Aer. salmonicida. These tests confirm that the isolates from flounder should be classified as Aer. salmonicida. Analysis of the fatty acids showed that the isolates were rather homogeneous but the values of the guanine plus cytosine content of the DNA of the bacteria varied too much for any conclusion to be drawn on their taxonomic location. The strains examined exhibited several biochemical characters that differed from those of the type strains of Aer. salmonicida subsp. salmonicida and Aer. salmonicida subsp. achromogenes. The results suggest that these 'atypical', cytochrome oxidase-negative variants may form a new subspecies of Aer. salmonicida.

Aeromonas↗

PubMed1987

Atypical isolates of Brucella abortus from Canada and the United States characterized as dye sensitive with M antigen dominant.

A total of 41 Brucella isolates, examined by standard biotyping procedures, were found to be similar to Brucella abortus biovar 2 in dye sensitivity but had a dominant M antigen. Oxidative metabolic tests performed on 39 of the isolates confirmed them as B. abortus. Additional biochemical and bacteriophage susceptibility studies were performed on 35 of the isolates. The isolates had identical reactions in the various tests, except for one isolate which was resistant to lysis by all phage strains used. Two isolates were injected into guinea pigs and shown to be virulent. The isolates described in this study appear similar to atypical Brucella isolates previously reported in the United Kingdom and the United States and may form the basis of a new biovar, B. abortus biovar 10.

Animals↗

PubMed1996

scbA from Streptococcus crista CC5A: an atypical member of the lraI gene family.

A new member of the lraI family of putative adhesin genes was cloned, from Streptococcus crista CC5A, and sequenced. The gene, scbA appears to be part of an ABC transport operon and encodes a putative peptide of 34.7 kDa. The protein contains a signal sequence with residues 17 to 21 (L-A-A-C-S) matching the consensus sequence for the prolipoprotein cleavage site of signal peptidase II. ScbA is 57 to 93% identical, at the amino acid level, with the five previous sequenced members of the LraI family. Surprisingly, ScbA does not exhibit adhesion properties characteristic of the other LraI proteins. Strain CC5A bound poorly to saliva-coated hydroxyapatite and did not coaggregate with Actinomyces naeslundii PK606. An scbA insertion-duplication mutation that abolished expression (of ScbA was created. There was no difference in fibrin binding between this mutant and wild-type CC5A. Since it is possible that ScbA could play a role in corncob formation between S. crista and Fusobacterium nucleatum, this property was examined. The mutant strain retained the ability to form corncobs. On the basis of the lack of adhesin properties it appears that ScbA is an atypical member of the LraI family.

Adhesins, Bacterial↗

PubMedDate not supplied

[Modern views on the efficacy of different antibacterial preparations in the treatment and prophylaxis of inflammatory processes in patients after transurethral local ultrasonic hyperthermia of the prostate].

Extensive clinical investigation was accomplished to study the influence of three antibacterial preparations groups (tetracyclines, aminoglycosides and fluorochinolons) on the phagocytic-macrophages and the immune systems in patients, to whom transurethral local microwave hyperthermia (TLMH) of prostate was performed for its benign hyperplasia. The data obtained witness high efficacy of fluorochinolons group preparation (tavanic) toward bacteria of different nosologic groups, as well as to their atypical forms. Pronounced efficacy and simplicity of application of the preparation had allowed to recommend its wide use in urologic practice.

Anti-Bacterial Agents↗

PubMed2003

[RNA responsible for conferring a DNase I sensitive structure on albumin gene in assembled chromatin].

Although the set of genes is virtually the same in all tissues,differential gene expression is appeared in cells of different kinds. Differentiation and ageing are associated with regulation of gene expression that is a fundamental mechanism in eukaryotic development and survival. The sensitivity to DNase I of actively transcribed genes seems to be a general phenomenon. The purpose of the study is to test whether RNAs obtained from different organs or cells can enhance susceptibility of albumin gene to DNase I digestion in BALB/c mouse brain chromatin assembled.RNAs extracted from rat liver, lung, kidney, brain, tRNA from yeast and synthesized RNAs (23 nt completed with mouse alb gene) were added to a system of chromatin reconstitution that was achieved by dialysis from high ionic strength solution. Assembled chromatin was digested with DNase I (12.5 microg/mL) at 20 degrees for 1 min, then PCR assay was used to detect the level of albumin gene digested. PCR products (1200 bp) were run on a 6% polyacylamide gel and analyzed by silver stain assay. RNAs from different organs and synthesized RNAs all increased the sensitivity of albumin gene to DNase I attack in mouse assembled chromatin. The effect was more obvious in liver and lung RNAs than in kidney and brain ones. tRNA from yeast did not enhance the sensitivity of albumin gene to DNase I digestion. RNA increased albumin gene sensitivity to DNase I in a dose-dependent manner. We report here for the first time that RNAs can enhance susceptibility of albumin gene to DNase I digestion. The effect is associated with RNA sources or sequences. It is generally agreed that the formation of gene sensitivity to DNase I, by unfolding of a tightly packed chromatin fiber, is the first step in gene activation, then RNAs that recognize complementary DNA sequences may be the specific factors that affect DNA supercoiling and determine the sensitivity of gene to DNase I digestion. Here we describes "RNA Population Gene Activating Model" that gives a logical interpretation of events leading to expression of specific genes during normal development and differentiation, in the same time,explains ageing and oncogenesis. Gene expression in eukaryotic cells requires two level regulations. The first may be controlled by RNAs that locate complementary regions within the genomes and make these regions loosened potentially, and the second is mainly involved in sequence specific and nonspecific proteins by which genomic regions bound by RNAs are unfolded. In eukaryotic cells, RNA fragments cleaved from all transcripts mix together to form "RNA populations" in which the majority is intron RNA. Every type of RNA fragments and its homologous sequences act as a group to form certain concentration in which repetitive sequences are more effective. If it is considered that there are many groups of RNA fragments in a particular cell,then different groups of RNA fragments are presented in dissimilar cell types of differentiation. Between DNA replication and nucleosome formation, RNA fragments in nuclear liquid will compete with DNA for binding to complement regions, then the chromatin regions bound to RNA can not be wrapped to form typical nucleosomes. After DNA doubles and is divided into 2 cells, these regions containing atypical nucleosomes become loose by function of non-histone. Transcriptionally active regions of chromatin are loose conformation but loosened regions are not always transcriptionally active. In every division, cells suffer in the described procedure that genes express RNAs, then RNAs recognize and imprint DNA. There are different RNA populations in different cells so that they imprint different genes, which is the primary mechanism by which same genes have expression distinctness. Since loosened genes are similar to bacterial operator system, factors in environment around cells play roles in inducing different gene expression to form different RNA population, which is the primary reason of cell differentiation. RNA population produced by certain impressions in genome can not imprint to form the same ones, otherwise immortal cells will be emerged, so that this program also controls ageing and oncogenesis.

English Abstract↗

PubMed2006

Identification of Bruton tyrosine kinase mutations in 12 Chinese patients with X-linked agammaglobulinaemia by long PCR-direct sequencing.

X-linked agammaglobulinaemia (XLA) is an immunodeficiency caused by Bruton tyrosine kinase (BTK) gene mutations. The disease is characterized by recurrent bacterial infections and profound hypogammaglobulinemia with marked reduction or lack of mature B-cells in the peripheral blood. Molecular characterization of BTK gene provides an opportunity for definitive diagnosis of XLA patients, especially for those with atypical phenotype resulting in a milder or late-onset form of the disease. The diagnosis allows accurate carrier detection with subsequent genetic counselling and prenatal diagnosis. In this study, long polymerase chain reaction (PCR)-direct sequencing analysis of the BTK gene in 12 unrelated Chinese XLA patients had been performed. Eight recurrent mutations and four novel mutations were identified. This is the first report of Chinese cases from three different East Asia regions together, including Hong Kong, Singapore and mainland China. Future clinical and genetic information from the undiagnosed Chinese XLA patients may provide insight into the genotype-phenotype correlations of BTK gene.

Adolescent↗

PubMedDate not supplied

Mycologic and bacteriologic investigations of clinical sputum specimens in Lagos, Nigeria.

Of 1,358 sputum specimens collected from in- and out-patients of the Lagos University Teaching Hospital, LUTH, and examined between September 1985 and June 1987, 585 (43.0%) were positive with one or more bacterial and/or fungal species. A total of 19 genera comprising of about 25 species of bacteria and fungi were isolated. Bacteria formed 363 (26.7%) of the 1,358 specimens while fungi isolated were 222 (16.3%). The bacteria were Mycobacterium species 357 (26.3%) consisting of M. tuberculosis 341 (25.1%), atypical mycobacteria 13 (1.0%) and M. Bovis three (0.2%); while Nocardia asteroides accounted for six (0.4%). Amongst the various fungi isolated Candida species, 116 (8.5%) and Aspergillus species 47 (3.5%) were very prevalent. It is noteworthy that 28.5% of the clinical specimens had single aetiologic agents while 14.6% were polymicrobial.

Hospitals, University↗

PubMed1983

[The detection of the agent of Legionnaires' disease--a confirmation of Koch's postulates].

The genus Legionella, belonging to the family of Legionellaceae, comprises nowadays seven species, among which Legionella pneumophila might be the most important. The identification of the agent is difficult because L. pneumophila is very pretentious requiring peculiar conditions concerning culture medium, temperature, and time. The initial cultivation will succeed the best in an atmosphere enriched with CO2. The demonstration of serum antibodies will succeed by means of indirect immunofluorescence; recently the micro-agglutination test is vastly applied. The clinical picture of Legionellosis is characterized by an atypical pneumonia with a serious course in most cases. The Pontiac Fever is an illness with milder course than the classical form of Legionellosis. Erythromycin and Rifampicin are the chemotherapeutics of choice.

Agglutination Tests↗

PubMed1998

Molecular epidemiology of the aetiological agents of Lyme borreliosis.

Ten species are up to now recognized among Borrelia burgdorferi sensu lato complex. Among those, only three (Borrelia burgdorferi sensu stricto, B. garinii and B. afzelii) are reported to be pathogenic for humans and each responsible for a predominant clinical form of Lyme borreliosis. Each species is characterized by its vectors (Ixodidae), its host spectrum, its organotropism (for the pathogenic ones) and its geographical repartition. Borrelia are strictly parasitic and essentially clonal bacteria. Our goal was to explore the diversity of this bacterial complex. We selected, by several molecular markers, atypical isolates and compared them to already known species representative strains by RFLP or sequencing. The results show an unexpected diversity at a level which could be a species one leading to the conclusion that the structure of the Borrelia burgdorferi sensu lato complex is a high number of small (by their populations) clones among which emerge some large ones usually corresponding to the pathogenic species. Our data also allow to speculate on when, where and how these species evolved and migrated.

Animals↗

PubMed1992

DNA melting within stable closed complexes at the Escherichia coli rrnB P1 promoter.

Several transcription complexes are shown to form on the E. coli ribosomal rrnB P1 promoter in vitro. These include two closed complexes that are sensitive to heparin attack, and one open complex. The closed complexes are unusual in that they are both highly specific and stable, properties associated with the atypical DNA sequence of this promoter. The effector ppGpp does not prevent closed complex formation but does reduce the level of open complexes that form.

Adenosine Triphosphate↗

PubMed1991

Slowly resolving, chronic, and recurrent pneumonia.

Slowly resolving, chronic, and recurrent pneumonias are clinical patterns that are often misunderstood and mistreated. This article reviews the natural history, clinical presentation, roentgenography, bacteriology, and relation to underlying illnesses of each of these atypical forms of community-acquired pneumonia. Standard definitions are presented and provide the physician with a means to classify the pneumonias. Appropriate diagnostic evaluation and therapy are also discussed.

Anti-Bacterial Agents↗

PubMed1998

A novel mutation at a probable heme-binding ligand in neutrophil cytochrome b558 in atypical X-linked chronic granulomatous disease.

A membrane-bound cytochrome b558, a heterodimer consisting of gp91-phox and p22-phox, is a critical component of the superoxide (O2-)-generating reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in phagocytes. Chronic granulomatous disease (CGD) is characterized by recurrent bacterial infection caused by a defect of the oxidase. Both subunits are absent from phagocytes in typical X-linked recessive CGD patients who are primarily defective in gp91-phox. We report here an atypical case of X-linked CGD in which neutrophils showed a complete absence of O2--forming NADPH oxidase activity, but a small amount (about 10% of control) of both subunits was detected by immunoblot analysis. Spectrophotometric studies of the neutrophils with a recently developed sensitive method gave no evidence for the heme spectrum in the cytochrome b558, of this CGD. Reverse transcription/polymerase chain reaction and sequence analysis revealed a C to T transition replacing histidine at amino acid position 101 (His101) by tyrosine in gp91-phox. These results provide evidence that His101 of gp91-phox is the one of the heme-binding ligands of cytochrome b558.

Adolescent↗

PubMed1992

Localized, aggregative, and diffuse adherence to HeLa cells, plastic, and human small intestines by Escherichia coli isolated from patients with diarrhea.

Adherence of diarrhea-associated Escherichia coli was studied by scanning electron microscopy. Enteropathogenic E. coli (EPEC) adherence factor-positive (EAF+) E. coli of EPEC serotypes (class I EPEC) adhered to plastic and human jejunal and ileal mucosa, similar to case and HeLa cells. Localized adherence, elongation of cell microvilli, and "locking" of the bacterial aggregates by the elongated microvilli were evident after incubation for 20 min. EAF+ E. coli adhered strikingly to mucus but rarely to M cells in Peyer's patch-associated epithelium. Most enteroaggregative E. coli (EAggEC) strains adhered to plastic, similar to HeLa cells. Some diffuse-adhering E. coli (DAEC) strains displayed no adherence to plastic but formed "dimples" on HeLa cells. Both EAggEC and DAEC adhered at lower levels to human small intestines (except M cells) than did EAF+ E. coli. In all cases of EAF+ E. coli, EAggEC, and DAEC, strains were found with atypical characteristics. The data demonstrate the unique adherence characteristics of EAF+ E. coli, EAggEC, and DAEC.

Adhesins, Escherichia coli↗

PubMed2004

Disruption of the peroxisomal citrate synthase CshA affects cell growth and multicellular development in Dictyostelium discoideum.

Non-mitochondrial citrate synthase catalyses citrate synthesis in the glyoxylate cycle in gluconeogenesis. Screening Dictyostelium discoideum mutants generated by insertional mutagenesis isolated a poor-growing mutant that displayed aberrant developmental morphology on bacterial lawns. Axenically grown mutants developed normally and formed mature fruiting bodies on buffered agar. The affected locus encoded a novel protein (CshA) that was homologous to glyoxysomal citrate synthase. cshA was expressed maximally during vegetative growth and gradually decreased through subsequent developmental stages. An in vitro citrate synthase assay revealed that cshA disruption resulted in a 50% reduction in enzyme activity, implicating CshA as an active citrate synthase. The amino-terminus of CshA was found to have an atypical mitochondrial targeting signal, instead containing a unique nonapeptide sequence (RINILANHL) that was homologous to the conserved peroxisomal targeting signal 2 (PTS2). CshA protein was shown to be localized in the peroxisomes, and the RINILANHL sequence only efficiently targeted the peroxisomal green fluorescent protein. The growth defect of cshA(-) cells was associated with the impairment of phagocytosis and fluid-phase endocytosis, independent from cytokinesis. Disrupted multicellular development on bacterial lawns resulted from the abnormal susceptibility to the environmental conditions, perhaps because of citrate insufficiency. Taken together, these results provide new insights into the function of peroxisomal citrate synthase in cell growth and multicellular development.

Amino Acid Sequence↗

PubMed1985

[Clinical picture of bacterial pneumonias and their differential diagnosis].

Under the influence of antibiotic therapy, bacterial pneumonias have undergone a remarkable change in the last few decades. Individual forms of pneumonia can be distinguished morphologically by their localization, the way in which they spread, their limitations, and their course. Clinically, opportunistic bacterial infections predominate. Increasingly, secondary pneumonias are observed in poststenotic areas, areas of infarction, in hypostatic areas, after aspiration, and in previously damaged lobes. Radiologic criteria for differentiating from atypical pneumonias (viruses, mycoplasmas and chlamydia) are discussed.

Bacterial Infections↗