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At least 667 records · Page 37Linked to original sources
PubMed2002

Molecular characterization of Candida spp. isolated from the oral cavities of patients from diverse clinical settings.

Infections by Candida spp. have increased in medical importance over the past few decades. Our understanding of species identification, commensalisms, pathogenicity, person-to-person spread, and the development of antifungal resistance within specific strains has been greatly enhanced by the utilization of molecular epidemiological methodology. The aim of the current research was to assess the quantity, species and molecular characterization of oral yeast isolates from well-defined cohorts of immunocompetent patients from a diverse range of clinical settings. Oral rinse samples were assessed for the growth of yeast and degree of colonization. Isolates were defined to the species level by both phenotypic and molecular methods and strains were further genotypically subtyped. Significant variation was shown to exist in the number, species and genotypic subgroups of yeast isolated from the oral cavity in different patient groups. This variation could be attributed to the local oral conditions unique to these patient groups.

Adult↗
PubMed2001

Oral administration of unmodified colonic but not small intestinal antigens protects rats from hapten-induced colitis.

Colonic administration of a hapten, 2,4,6-trinitrobenzene sulphonic acid (TNBS) has been shown to induce colitis in rats. We are using this model to investigate the role of colonic antigens in the immunopathology. In this study, we show that colitis can be suppressed by oral administration of haptenized colonic antigens prior to the TNBS enema. Moreover, our data suggest that haptenization of the colonic antigens is not essential because oral feeding of non haptenized colonic antigens too protects rats from TNBS-induced colitis. Thus, unmodified colonic antigens may be involved in the induction of oral tolerance, and possibly in the pathogenesis in this model of colitis. Further, we show that the protective immunity or oral tolerance induced by non haptenized colonic antigens can be passively transferred to naïve rats by mesenteric T lymphocytes. Interestingly, oral feeding of small intestinal antigens, haptenized and non haptenized, does not protect rats from colitis, suggesting a specific role for colonic antigens. These data underscore the usefulness of this rat model in the identification of pathogenic antigens in colitis and in the development of therapeutic strategies based on oral tolerance.

Administration, Oral↗
PubMed1997

Identification of a new pathogen-induced member of the subtilisin-like processing protease family from plants.

By using biochemical, immunological, and molecular strategies we have identified and cloned a cDNA encoding a protease from tomato (Lycopersicon esculentum) plants (P69B) that is part of a proteolytic system activated in the plant as a result of infection with citrus exocortis viroid. This new protease is closely related, in terms of amino acid sequence and structural organization, to the previously identified pathogenesis-related subtilisin-like protease (Tornero, P., Conejero, V., and Vera, P. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 6332-6337). The 745-residue amino acid sequence of P69B begins with a cleavable signal peptide, contains a prodomain and a 631-residue mature domain which is homologous to the catalytic modules of bacterial subtilisins and eukaryotic Kex2-like proteases. Within the catalytic domain, the essential Asp, His, and Ser residues that conform the catalytic triad of this family of proteases are conserved in P69B. Northern blot and reverse transcriptase-polymerase chain reaction analysis demonstrated widespread induced expression of the 2.5-kilobase hybridizing mRNA in plant tissues as a consequence of viroid infection. We propose that P69B is a member of a complex gene family of plant Kex2/subtilisin-like proteases presumably involved in a number of specific proteolytic events activated during pathogenesis in plants and that takes place in the extracellular matrix.

Amino Acid Sequence↗
PubMed2007

In vivo characterization and therapeutic efficacy of a C5-specific inhibitor from the soft tick Ornithodoros moubata.

The involvement of complement (C) in inflammatory diseases has driven the search for agents capable of inhibiting dysregulated complement activation. Many of these reagents inhibit the C3 convertases during the early stages of the cascade. However, a drawback of total systemic C inhibition, particularly in longterm treatment of chronic disease, is potentiation of infection and immune complex disease due to an inability to opsonize complexes and foreign cells and to lyse pathogens. Recent identification of a C5-binding protein in the salivary gland of the soft tick Ornithodoros moubata has enabled development of a terminal pathway-specific reagent, OmCI, with potential to ameliorate disease while leaving key physiological processes unaffected. Here we demonstrated that OmCI has broad cross-species activity. When given intravenously to rodents, OmCI totally ablated complement hemolytic activity, which gradually restored as C5 was resynthesized. The circulating half-life of OmCI was 30 h, demonstrating a much slower clearance than other small, biological agents. Using C5-sufficient and C5-deficient mice we showed that prolonged half-life was due to binding to plasma C5. Surface plasmon resonance analysis of C5 binding to OmCI confirmed a high binding affinity with a slow dissociation rate. OmCI was effective in preventing experimental autoimmune myasthenia gravis induced by passive transfer in normal Lewis rats. OmCI ablated clinical disease, reduced C3 and C9 deposition at the neuro-muscular junction, and effected a marked reduction in cellular infiltration at this site. These data offer exciting prospects for targeted treatment of complement-mediated diseases without the detrimental inhibition of the opsonic roles of complement.

Animals↗
PubMed2002

Differentiation of nocardia species by PCR-randomly amplified polymorphic DNA fingerprinting.

Representatives of fifteen validly described and three non-validly described species of Nocardia were assigned to nineteen groups based on an optimised PCR-randomly amplified polymorphic DNA fingerprinting technique. Species specific banding patterns were recognised for the representatives of N. brasiliensis, N. crassostreae, N. farcinica, N. otitidiscaviarum and N. seriola. Unique banding patterns were also seen for the type strains of N. brevicatena, N. carnea, N. salmonicida, N. uniformis and N. vaccinii, and for the single representatives of "N. fusca", "N. pseudosporangifera", and "N. violaceofusca". More than one banding pattern was detected for the N. asteroides, N. flavorosea, N. nova, N. pseudobrasiliensis and N. transvalensis strains though in the case of the representative strains of N. nova and N. transvalensis the patterns were similar for each of these species. The results are in line with current trends in nocardial systematics thereby indicating that PCR-randomly amplified polymorphic DNA fingerprinting provides valuable data for the classification and identification of pathogenic nocardiae to the species level.

DNA Fingerprinting↗
PubMedDate not supplied

Sap beetles and mycotoxins in maize.

Sap beetles (Coleoptera: Nitidulidae) are important in vectoring mycotoxigenic species of Aspergillus and Fusarium to maize. Species examined are attracted to fungal and maize volatiles, and are resistant to most mycotoxins compared to maize ear-infesting caterpillars. They will invade ears damaged by birds or caterpillars or those ears that have poor husk coverage. An integrated control programme for these insects under development presently includes pheromones and host coattractants for trapping; identification and dispersal of pathogenic nematodes and fungi; identification of maize varieties cross-resistant to mycotoxigenic fungi and other insects, and the potential mechanisms involved; and formulations of insecticides for single treatment, low active ingredient, selective control of insect pests of ears including sap beetles and caterpillars that preserve naturally occurring predators and parasites. Autoinoculative devices are also being tested to use sap beetles to deliver biocompetitors of mycotoxigenic fungi to maize.

Adaptation, Physiological↗
PubMed1990

Identification of extracellular siderophores of pathogenic strains of Aspergillus fumigatus.

Clinical and environmental isolates of Aspergillus fumigatus synthesized extracellular siderophores when grown in defined medium. Six hydroxamate siderophores were purified from culture filtrates and identified by thin layer chromatography. The most prominent siderophore was identified as N,N',N"-triacetylfusarinine C and the second most prominent siderophore was identified as ferricrocin. In addition, a hydrolytic product of N,N',N"-triacetylfusarinine C was identified. Three other siderophores were present in smaller amounts and were not identified. Since the same siderophores were produced by isolates from diseases of varying severity and from environmental material, it is unlikely that the extracellular siderophores function as virulence factors during infection. However, they may function as growth factors by mediating iron uptake by the fungus in the micro-environment of the inflammatory focus.

Aspergillus fumigatus↗
PubMed2002

Vertebral osteomyelitis: long-term outcome for 253 patients from 7 Cleveland-area hospitals.

We report a retrospective study of 253 patients with vertebral osteomyelitis (VO) who had long-term follow-up. Eleven percent of the patients died, residual disability occurred in more than one-third of the survivors, and relapse occurred in 14%. Median duration of follow-up was 6.5 years (range, 2 days to 38 years). Independent risk factors for adverse outcome (death or qualified recovery) were neurologic compromise, time to diagnosis, and hospital acquisition of infection (P< or =.004). Surgical treatment resulted in recovery or improvement in 86 (79%) of 109 patients. Magnetic resonance images (110 patients) were often obtained late in the course of infection and did not significantly affect outcome. Often, relapse developed in individuals with severe vertebral destruction and abscesses, appearing some time after surgical drainage or debridement. Recurrent bacteremia, paravertebral abscesses, and chronically draining sinuses were independently associated with relapse (P< or =.001). An optimal outcome of VO requires heightened awareness, early diagnosis, prompt identification of pathogens, reversal of complications, and prolonged antimicrobial therapy.

Adolescent↗
PubMed1994

Nonradiometric ELISA-based quantitation and validation of polymerase chain reaction-amplified DNA, including detection of point mutations, without allele-specific amplification, or ligation.

We describe two simple novel procedures, one direct and the other involving hybridization, for the enzyme-linked immunosorbent assay (ELISA)-based detection, quantitation, and validation of polymerase chain reaction (PCR)-amplified DNA. Both procedures are applicable to any PCR reaction, and do not require specially synthesized or enzyme-tagged oligonucleotides. We obtained accurate quantitation of PCR-amplified human cc10kDa cDNA with a sensitivity of about 0.6 fmoles. This cDNA was also used to detect single-base insertions, deletions, and substitutions specifically. Additionally, we could readily distinguish zinc-finger Y chromosome-specific genomic sequences in mixtures of male and female cells and normal and mutant cystic fibrosis transmembrane conductance regulator (CFTR) gene sequences in crude fibroblast lysates. To our knowledge, this is the first report of point mutation detection in solution by ELISA without allele-specific amplification or ligation. These novel procedures have vast potential for basic and clinical applications, including gene expression studies, rapid screening of genetic diseases, detection of oncogene and anti-oncogene mutations, and identification of pathogens (e.g., HIV-1) in clinical specimens.

Base Sequence↗
PubMed2003

Shedding light on health and disease using molecular beacons.

The detection and identification of pathogens is often painstaking due to the low abundance of diseased cells in clinical samples. The genomic sequences of the pathogen can be amplified through methods such as the polymerase chain reaction and nucleic acid sequence-based amplification, but the nucleic acid targets are often lost among other unintended products of amplification. Novel nucleic acid probes known as molecular beacons have been developed allowing for the rapid and specific detection of genetic markers of a disease. Molecular beacons are hairpin-forming oligonucleotides labelled at one end with a quencher and at the other end with a fluorescent reporter dye. In the absence of target, the fluorescence is quenched. In the presence of target, the hairpin structure opens upon beacon/target hybridisation, resulting in the restoration of fluorescence. The ability to transduce target recognition into a fluorescence signal with high signal-to-background ratio, coupled with an improved specificity, has allowed molecular beacons to enjoy a wide range of biological and biomedical applications. Here, we describe the basic features of molecular beacons, review their applications in disease detection and diagnosis and discuss some of the issues and challenges of in vivo studies. The aim of this paper is to foster the development of new molecular beacon-based assays and to stimulate the application of this technology in laboratory and clinical studies of health and disease.

Animals↗
PubMed1992

General guidelines for clinical bacteriology. Infectious Diseases Society of America and the Food and Drug Administration.

This guideline summarizes recommendations for (1) developing cogent procedures for diagnosis and antimicrobial susceptibility testing; (2) developing quality-control parameters for the microbiological components of clinical trials; (3) continually updating U.S. Food and Drug Administration (FDA) guidelines; (4) reviewing microbiological recommendations from other groups, such as Microbiology Subcommittees of the National Committee for Clinical Laboratory Standards; and (5) improving the microbiological aspects of FDA package inserts for antimicrobial drugs. Sensitive and specific methods for isolation and identification of pathogens are essential to the proper conduct of clinical trials. Susceptibility tests should be performed in an accurate and reproducible fashion. Verification of results in a reference laboratory is encouraged to monitor quality control.

Anti-Bacterial Agents↗
PubMed2000

Untangling tau-related dementia.

Abundant cytoplasmic inclusions consisting of aggregated hyperphosphorylated protein tau are a characteristic pathological observation in several neurodegenerative disorders such as Alzheimer's disease, Pick's disease, frontotemporal dementia, cortico-basal degeneration and progressive supranuclear palsy. The recent finding that mutations in the tau gene are responsible for frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) has provided convincing evidence that tau protein plays a key role in neurodegeneration. In the short period since the identification of pathogenic mutations in tau, remarkable progress has been made in understanding some of the mechanisms by which these mutations lead to neurodegeneration. Understanding the disease processes will hopefully provide us with new leads in developing effective therapies for dementia.

Dementia↗
PubMed1998

Protothecosis: an unusual cause of chronic subcutaneous and soft tissue infection.

Protothecosis of subcutaneous and soft tissues is a rare occurrence in humans. We present two patients with chronic subcutaneous protothecosis affecting the elbow and foot respectively. Both patients had been treated with local corticosteroid injections and had recent exposure to water. The diagnosis was made histopathologically in both cases and confirmed by culture in one case. Histopathology showed typical Protothecal sporangia with surrounding mixed inflammatory infiltrate including necrotizing granulomas. Organisms stained positively with periodic acid-schiff, Gomori's methenamine silver, and Gridley fungus stains. In one case, intravenous chemotherapy was required to eliminate the pathogens. Histopathologic identification of the organisms is vital to ensure adequate therapy and avoid chronic smoldering infection.

Chronic Disease↗
PubMed2002

Identification of upper respiratory bacterial pathogens with the electronic nose.

OBJECTIVE: To use an electronic nose to identify common upper respiratory bacterial pathogens. STUDY DESIGN: Controlled in vitro analysis. METHODS: Swabs of bacteria were obtained from in vitro samples. The specimens were vaporized and analyzed over the organic semiconductor-based electronic nose (Cyranose 320). Data from the 32-element sensor array were subjected to principal component analysis for depiction in two-dimensional space and differences in odorant patterns were assessed by calculating Mahalanobis distances. RESULTS: The electronic nose was able to distinguish between control swabs and bacterial samples. Furthermore, calculation of the Mahalanobis distances among the various bacteria demonstrated distinct odorant classes (Mahalanobis distance > or = 3). This demonstrates that the electronic nose could differentiate among various common bacterial pathogens of the upper respiratory tract, including Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenza, and Pseudomonas aeruginosa. CONCLUSIONS: The electronic nose represents a novel method to identify potential upper respiratory infections and to discriminate among common upper respiratory bacterial pathogens. This technology could provide a rapid means to identify organisms causing upper respiratory infections.

Bacteria↗
PubMedDate not supplied

Evaluation of modified New York City carbohydrate medium for the speciation of Neisseria.

A comparative study of modified New York City carbohydrate medium, Minitek (BBL Microbiology Systems, Cockeysville, Md.) and cystine-trypticase agar was conducted for determination of the relative accuracies of these media in the identification of pathogenic Neisseria. Of 170 isolates of Neisseria gonorrhoeae, 169 were correctly identified by New York City carbohydrate media, 131 by Minitek, and 117 by cystine-trypticase agar. Of the 72 isolates of Neisseria meningitidis tested, all were accurately speciated by New York City carbohydrate media, whereas Minitek and cystine-trypticase agar identified 61 and 49 strains, respectively. The greater reliability of New York City carbohydrate media is accompanied by advantages not offered by the other media.

Agar↗
PubMed2005

Ultrasound markers of fetal infection part 1: viral infections.

Diagnosis of fetal infection has depended on identification of pathogens by means of microbiological cultures, immunologic techniques, and special molecular biology techniques that can identify organisms known or suspected of being associated with adverse outcomes of pregnancy. Rubella, cytomegalovirus (CMV), herpes simplex virus (HSV), and human immunodeficiency virus (HIV), for example, are capable of gaining access to the amniotic cavity and producing fetal infection, even when amniotic membranes are intact. Intrauterine invasion by viruses can be associated with maternal symptoms of infection or can be completely silent. In many instances extensive fetal compromise with irreversible structural damage or fetal death will have occurred by the time infection is confirmed by culture or other histopathological methods. The evidence of fetal infection may be as subtle as nascent intrauterine growth restriction (IUGR), mildly inappropriate calcification of fetal organs, placenta, cord, and membranes, and failure to adequately develop fetal fat reserves. The evidence of infection may be as dramatic as obvious fetal malformation, severe central nervous system structural damage, or fetal death. Sonography is capable of detecting most of the grave alterations and some of the subtle effects that are typical of fetal infection.

Cytomegalovirus Infections↗
PubMed2006

An RNA aptamer that distinguishes between closely related human influenza viruses and inhibits haemagglutinin-mediated membrane fusion.

Aptamers selected against various kinds of targets have shown remarkable specificity and affinity, similar to those displayed by antibodies to their antigens. To employ aptamers as genotyping reagents for the identification of pathogens and their strains, in vitro selections were carried out to find aptamers that specifically bind and distinguish the closely related human influenza A virus subtype H3N2. The selected aptamer, P30-10-16, binds specifically to the haemagglutinin (HA) region of the target strain A/Panama/2007/1999(H3N2) and failed to recognize other human influenza viruses, including another strain with the same subtype, H3N2. The aptamer displayed over 15-fold-higher affinity to the HA compared with the monoclonal antibody, and efficiently inhibited HA-mediated membrane fusion. These studies delineate the application of aptamers in the genotyping of viruses.

Amino Acid Sequence↗