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Results for “pathogenicity classification”

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At least 595 records · Page 33Linked to original sources
PubMed1996

[Antiganglioside antibodies in neuropathies and motor neuronopathies].

The presence of antiganglioside antibodies is associated with several neurologic disorders. These antibodies recognize several epitopes, generally saccharides present in these glucolipids. The presence of antiGM antibodies has been described in certain clinical syndromes, the main one being multifocal motor neuropathy with and without conduction blocks. The frequency of antiGM1 class IgM antibody falls between 20 and 80% in this disease. Axon predominant Guillain-Barré syndrome is also associated with high titers of antiGM1 antibodies, although in this case class IgG is implicated. The most important association to date has been established between Miller-Fisher syndrome and the presence of antiGQ1b antibodies. Several authors have reported molecular similarities among these gangliosides and bacterial lipopolysaccharides, mainly Campylobacter iejuni. The principal aims in the study of antiganglioside antibodies are to establish their pathogenic role as well as the clinical usefulness of analyzing for them, and to discover new specificities that aid in the diagnosis and classification of neuropathies, whether they are predominantly motor disorders or chronic sensory ones.

Antibodies↗
PubMed1998

A short history of plant virology. II. The twenties.

Plant virology, born at the end of the last century, consolidated during the Twenties. Important new viral diseases were described and their causal agents partially purified and characterized not least because of the development of methods and techniques. An interesting debate concerned the so called "intracellular bodies", which were finally demonstrated to be aggregates of virus particles. Discoveries mainly arrived from experimental investigations on tobacco mosaic virus, and concerned the identification of strains, the demonstration of antigenic property, and the protein nature of viruses. A new concept of virus drew great advantage from the first attempts of classification and nomenclature, and a debate on the living or non-living nature of viruses, universally accepted as a new class of pathogens, was opened. The idea of viruses as self-reproducing particles was first advanced, although on a controversial basis. On the contrary, there was only erratic investigations on the physiological alterations produced by viral diseases in plants and on the relationships between viruses and vectors. In spite of this gaps, the Twenties must be mentioned as the years of the turning-point towards a biochemical concept of viruses, which will be achieved in the next decade.

Antigens, Viral↗
PubMed1996

Quantifying water pathogen risk in an epidemiological framework.

Traditionally, microbial risk assessors have used point estimates to evaluate the probability that an individual will become infected. We developed a quantitative approach that shifts the risk characterization perspective from point estimate to distributional estimate, and from individual to population. To this end, we first designed and implemented a dynamic model that tracks traditional epidemiological variables such as the number of susceptible, infected, diseased, and immune, and environmental variables such as pathogen density. Second, we used a simulation methodology that explicitly acknowledges the uncertainty and variability associated with the data. Specifically, the approach consists of assigning probability distributions to each parameter, sampling from these distributions for Monte Carlo simulations, and using a binary classification to assess the output of each simulation. A case study is presented that explores the uncertainties in assessing the risk of giardiasis when swimming in a recreational impoundment using reclaimed water. Using literature-based information to assign parameters ranges, our analysis demonstrated that the parameter describing the shedding of pathogens by infected swimmers was the factor that contributed most to the uncertainty in risk. The importance of other parameters was dependent on reducing the a priori range of this shedding parameter. By constraining the shedding parameter to its lower subrange, treatment efficiency was the parameter most important in predicting whether a simulation resulted in prevalences above or below non outbreak levels. Whereas parameters associated with human exposure were important when the shedding parameter was constrained to a higher subrange. This Monte Carlo simulation technique identified conditions in which outbreaks and/or nonoutbreaks are likely and identified the parameters that most contributed to the uncertainty associated with a risk prediction.

Animals↗
PubMed1997

[A classification of virus-related neurological disease].

Virus-related neurological diseases (VRNDS) are classified according to, (1) the site of main pathologic changes, (2) the type of cells infected with (parasitized by) pathogenic viruses, (3) the species of causative viruses. In the acutenesis of the development of clinical manifections and (5) the length of latency (period between infection and the onset of the illness). VRNDs were classified into meningitides, encephalitides, myelitides and neuritides. The VRNDs in which nerve cells (neurons, neuroglial cells or both) are parasitized by pathogenic viruses can be called neuroinfective viral neurological diseases. The VRDs in which nerve cells can be called non neuro-infective neurological viral disease. VRNDs were classified into those by Papova viruses, those by Herpes viruses, those by Picornaviruses, those by Toga viruses, those by Flaviviruses, those by Paramyxoviruses, those by Rhabdoviruses, those by Arenaviruses, those by Buniaviruses and those by Retroviruses. VRNDs may develop acutely, subacutely on chronically. There are VRNDs that can be called progressive because their course is progressive and their outcome is fatal. Some VRNDs develop soon after primary infection and other VRNDs develop long after primary infection on reactivation of the virus.

Humans↗
PubMed2006

Erwinia tasmaniensis sp. nov., a non-phytopathogenic bacterium from apple and pear trees.

Bacteria were isolated from flowers and bark of apple and pear trees at three places in Australia. In Victoria, Tasmania and Queensland, strains with white colonies on nutrient agar were screened for dome-shaped colony morphology on agar with sucrose and were found to be closely related by several criteria. The isolates were not pathogenic on apples or pears. They were characterized by a polyphasic approach including microbiological and API assays as well as fatty acid methyl ester analysis, DNA-DNA hybridization and DNA sequencing. For molecular classification, the 16S rRNA cistron and the conserved genes gpd and recA of these bacteria were investigated. Together with other taxonomic criteria, the results of these studies indicate that the bacteria belong to a novel separate species, which we propose to name Erwinia tasmaniensis sp. nov., with the type strain Et1/99(T) (=DSM 17950(T)=NCPPB 4357(T)). From DNA-DNA hybridization kinetics, microbiological characteristics and nucleotide sequence analyses, this species is related to pathogenic Erwinia species, but also to the epiphytic species Erwinia billingiae.

Australia↗
PubMed2025

HCSeeker: A classification tool for human genetic variant hot and cold spots designed for PM1 and benign criteria in the ACMG-AMP guideline.

PURPOSE: The PM1 criterion, which states that a variant is located in a mutational hot spot and/or critical and well-established functional domain without benign variation (such as the active site of an enzyme), is considered moderate evidence for assessing its pathogenicity. Although guidelines from the American College of Medical Genetics and Genomics and the Association for Molecular Pathology are widely adopted, the PM1 criterion remains limited from lacking a reliable database of variant hot spots. Compared with hot spots, cold spots are neglected by the guidelines. To improve variant classification, we suggest including cold spots for supporting benign classifications. Consequently, we have developed the HCSeeker to provide data support for PM1 and the "Benign" criteria. METHODS: HCSeeker uses the Kernel Density Estimation and the Expectation-Maximization algorithm to identify hot- and cold-spot regions. RESULTS: Through HCSeeker, we identified 988 hot spots and 682 cold spots across 889 genes and provided a public database (http://www.genemed.tech/hcseeker/) for researchers and clinicians to query variant locations, facilitating the application of American College of Medical Genetics and Genomics and the Association for Molecular Pathology PM1 or "Benign" criteria. CONCLUSION: We developed the HCSeeker tool, which can effectively identify variant hot and cold spots within genes to enhance the interpretability of gene variants.

Humans↗
PubMed1991

Mycotic aneurysm of the suprarenal aorta secondary to Streptococcus pneumoniae: an unusual pathogen.

Mycotic aneurysms of the suprarenal aorta are rare lesions, accounting for less than 1% of aortic reconstructions for aneurysmal disease. The bacteriology of these lesions differs from the infrarenal aneurysms and primarily consists of Gram-negative organisms. We report an unusual case of an 87-year-old man successfully treated for a ruptured mycotic suprarenal aortic aneurysm caused by Streptococcus pneumoniae. We have not seen a previously reported case where this pathogen has been associated with a suprarenal mycotic aneurysm. The unique bacteriology of these aneurysms is reviewed along with theories of etiology and their classification. The current management of these aneurysms is summarized.

Aged↗
PubMed1998

Otitis media.

This article discusses the different classifications of otitis media, with particular emphasis on acute otitis media and otitis media with effusion. The change in antimicrobial resistance of the common pathogens presents new challenges to clinicians who treat these disorders.

Acute Disease↗
PubMed1951

A new member of the psittacosis-lymphogranuloma group of viruses that causes infection in calves.

From portions of intestine and feces of apparently normal calves, a virus that produces elementary bodies was procured in guinea pigs and in embryonated eggs. Morphologically and tinctorially this virus closely resembled members of the psittacosis-lymphogranuloma group of viruses and it shared a common antigen or antigens with them. Comparison of serological, pathogenic, and other properties indicated that this virus from calves is a new member of the psittacosis-lymphogranuloma group and in keeping with classification practices it is provisionally named Miyagawanella bovis. Miyagawanella bovis when fed to experimental calves established an infection in the intestinal tract that resembled the inapparent infection seen in natural cases but failed to produce evident disease. Ability of the virus to infect experimental animals by feeding, and its presence in feces of infected animals indicate its natural mode of spread. This method of dissemination and persistence of virus for long periods of time in infected animals suggested the virus should be widespread and more than 60 per cent of the calves in the vicinity of lthaca were found to be infected.

Animals↗
PubMed1987

Antigenic characterization of the oligosaccharide portion of the lipooligosaccharide of nontypable Haemophilus influenzae.

Monoclonal antibodies (MAbs) directed against epitopes in the oligosaccharide portion of the lipooligosaccharide (LOS) of nontypable Haemophilus influenzae (NTHI) were used to characterize the LOS of this pathogen. Western blot (immunoblot) analysis with four LOS-specific MAbs and proteinase K-derived LOS preparations from 69 NTHI strains allowed the classification of these strains into nine LOS antigenic groups. The use of these MAbs in a more sensitive colony blot radioimmunoassay system together with these same NTHI strains identified 14 LOS antigenic groups. Extensive cross-reactivity was detected between the LOS epitopes of these NTHI strains and the LOS of H. influenzae type b. The epitopes recognized by these MAbs were not accessible to antibody on the surface of every strain. These LOS epitopes were also not stably expressed by NTHI growing in vitro; the observed frequency of LOS antigen variation ranged from 1 to 24% when large numbers of colonies of NTHI strains were screened for reactivity with the LOS-directed MAbs in the colony blot radioimmunoassay. This LOS antigenic variation was sometimes associated with alterations in the profile of the LOS molecule as resolved by dodecyl sulfate-polyacrylamide gradient gel electrophoresis followed by staining with silver. These data indicate that considerable antigenic diversity exists among NTHI strains with regard to the oligosaccharide epitopes in their LOS molecules.

Antibodies, Bacterial↗
PubMed2006

Genetic and histopathologic evaluation of BRCA1 and BRCA2 DNA sequence variants of unknown clinical significance.

Classification of rare missense variants as neutral or disease causing is a challenge and has important implications for genetic counseling. A multifactorial likelihood model for classification of unclassified variants in BRCA1 and BRCA2 has previously been developed, which uses data on co-occurrence of the unclassified variant with pathogenic mutations in the same gene, cosegregation of the unclassified variant with affected status, and Grantham analysis of the fit between the missense substitution and the evolutionary range of variation observed at its position in the protein. We have further developed this model to take into account relevant features of BRCA1- and BRCA2-associated tumors, such as the characteristic histopathology and immunochemical profiles associated with pathogenic mutations in BRCA1, and the fact that approximately 80% of tumors from BRCA1 and BRCA2 carriers undergo inactivation of the wild-type allele by loss of heterozygosity. We examined 10 BRCA1 and 15 BRCA2 unclassified variants identified in Australian, multiple-case breast cancer families. By a combination of genetic, in silico, and histopathologic analyses, we were able to classify one BRCA1 variant as pathogenic and six BRCA1 and seven BRCA2 variants as neutral. Five of these neutral variants were also found in at least 1 of 180 healthy controls, suggesting that screening a large number of appropriate controls might be a useful adjunct to other methods for evaluation of unclassified variants.

Alleles↗
PubMed2003

Acute otitis media disease management.

A first step in management decisions regarding otitis media must focus on accurate diagnosis to distinguish normal from acute otitis media (AOM) from otitis media with effusion (OME) or a retracted tympanic membrane without middle ear effusion. There are several classification schemes for AOM that may impact management decisions: patients with acute, persistent, recurrent, or chronic AOM may have a different distribution of bacterial pathogens and a different likelihood of success from antimicrobial therapy. Patient age, prior treatment history and daycare attendance are other important variables. The natural history of AOM without antibiotic treatment is generally favorable; however, from the few studies available, this is difficult to quantitate because the diagnosis was infrequently confirmed by tympanocentesis leaving the possibility that many patients entered into these trials may not have had bacterial AOM. Antibiotic choices should reflect pharmacokinetic/pharmacodynamic data and clinical trial results demonstrating effectiveness in eradication of the most likely pathogens based on tympanocentesis sampling and antibiotic sensitivity testing. Thereafter, compliance factors such as formulation, dosing schedule and duration of treatment and accessibility factors such as availability and cost should be taken into account. The increasing prevalence of antibiotic resistance among AOM pathogens and the changing susceptibility profiles of these bacteria should be considered in antibiotic selection. Current best practice recommends amoxicillin for uncomplicated AOM; continuing or switching to an alternative antibiotic based on clinical response after 48 hours of therapy; and selection of second line antibiotics as first line choices when the patient has already been on an antibiotic within the previous month or is otitis prone. Preferred second-line agents frequently noted in various guidelines include amoxicillin/clavulanate, cefdinir, cefpodoxime, cefprozil, and cefuroxime. Three injections of ceftriaxone or gatifloxacin (when approved) or diagnostic/therapeutic tympanocentisis (when approved) become a third-line treatment option. No single antibiotic or management strategy is ideal for all patients.

Acute Disease↗
PubMedDate not supplied

[Which mast cell inhibition is to be used in ophthalmology?].

Correct treatment of allergic conjunctivitis cannot be achieved bay simple classification into two categories, i.E. as perennial or seasonal conjunctivitis. It is important to distinguish the different forms, each of which have a different pathogenicity and a different treatment. Opticron is the reference product. All others drugs must be evaluated by randomized double-masked studies.

Conjunctivitis, Allergic↗
PubMedDate not supplied

[Venous vascular changes in prostatic adenomyomatosis].

An important role should be attributed to the prostatic venous complex and to its pathology in the clinical aspects of prostate adenoma. This appears to be responsible for the acute retention of urine as well as for the hemorrhages that accompany the disease. The authors, on the occasion of 50 adenomectomies by the trans-vesical method, have carried out histological investigations on the excised tissues and made a correlation with the microscopic aspects of the peri-orificial urethra and of the prosthatic urethra, in connection with the changes noted in the venous system. The veins have displayed more or less important changes in all the cases. These consisted in stasis, lacunar dilatations or of the varicose type, inflammations or parietal modifications of a different origin. At the same time were noted signs of inflammation in the submucosa as well as in the muscular layer of the bladder wall, which appeared to be distrophic. The pathogenic role is stressed of the venous system in the developement of the clinical aspects especially in type II and III of a personal classification.

Aged↗
PubMed2026

RNA sequencing resolves a novel noncanonical splice-region variant in PHKA2 causing glycogen storage disease type IX α2: a case report.

BACKGROUND: Glycogen storage disease type IX α2 (GSD IX α2) is an X-linked hepatic glycogenosis caused by pathogenic variants in PHKA2. Noncanonical splice-region variants located outside the invariant GT/AG dinucleotides pose significant interpretive challenges, as in silico predictions alone are often insufficient for definitive classification. CASE DESCRIPTION: We report a 2.9-year-old boy presenting with short stature, hepatomegaly, markedly elevated aminotransferases, fasting hypoglycemia with ketonuria, hypercholesterolemia, coagulation parameter abnormalities (decreased fibrinogen and prolonged thrombin time), and histological evidence of early hepatic fibrosis as demonstrated by Masson's trichrome staining (portal fibrosis and perisinusoidal fibrosis). Whole-exome sequencing (WES) identified a hemizygous, previously unreported PHKA2 variant [NM_000292.3:c.2517+5G>T, genomic location (GRCh38): NC_000023.11: g.18907895G>T], initially classified as a variant of uncertain significance (VUS) under American College of Medical Genetics and Genomics (ACMG) criteria. RNA sequencing of peripheral blood leukocytes demonstrated predominant exon 22 skipping in 94.2% of informative junction reads, predicting a frameshift and premature termination codon [p.(Gly788Profs*74)] with predicted loss of the C-terminal CBL 2 subdomain. Incorporating this transcript-level evidence, the variant was reclassified as pathogenic (PVS1 + PM2_Supporting + PP4). Following dietary management with uncooked cornstarch supplementation, the patient showed progressive biochemical improvement over a 2.2-year follow-up. CONCLUSIONS: This case expands the mutational spectrum of PHKA2 and demonstrates that RNA sequencing of accessible tissues is a practical and diagnostically informative strategy for resolving noncanonical splice-region variants in pediatric hepatic GSD. Early hepatic fibrosis detected by histological examination before age 3 years underscores the importance of longitudinal hepatic surveillance in GSD IX α2.

Glycogen storage disease type IX α2 (GSD IX ↗
PubMedDate not supplied

235 cases of excessive daytime sleepiness. Diagnosis and tentative classification.

A series of 235 consecutive patients refferred to the Stanford University Sleep Disorders Clinic with the complaint of excessive daytime sleepiness (EDS) were investigated extensively. A satisfactory final diagnosis involving a consistent syndrome or pathogenic process was made in all but 7 patients. In the course of this work a variety of tests, including prolonged polygraphic monitoring of multiple variables and CSF measurements before and after probenecid ingestion, were utilized. Different syndromes were confirmed (harmonious hypersomnia, subwakefulness syndrome); the definitions of others were clarified and extended (narcolepsy, drug dependency, periodic hypersomnia associated with menstruation, upper airway sleep apnea in children). Two new entities were tentatively identified (narcolepsy with sleep apnea, the neutral state syndrome). Narcolepsy and upper airway sleep apnea accounted for the majority of the cases (199). A strategic schema utilizing specific categories and frequency of occurrence in the case series is presented to improve the diagnosis of the complaint of excessive daytime sleepiness by the practicing physician. This case series was analysed in order to develop tentatively a meaningful nosology.

Adolescent↗
PubMed1989

[Classification of spirochetes infecting man].

The systematics od spirochetes must from now own fulfil the genomic criteria recently laid down. Formerly, these parasites were classified on the basis of various phenotypic features, among which the pathogenicity and epidemiological criteria played the predominant role. At present, the order of Spirochaetales is divided into two families: Spirochaetaceae and Leptospiraceae. Two of the four genera of Spirochaetaceae, Treponema and Borrelia, include species that are pathogenic to man. Among Leptospiraceae, only one genus, Leptospira, has pathogenic species. The phenotypic characteristics of the various taxons are detailed, the role of each actor (causative agent, vector, reservoir) in the main pathological complexes and the progress of genotypic studies are briefly described.

Humans↗
PubMed1985

[Classification, diagnosis and therapy of pneumonia].

The different patterns of pneumonia are classified and show the various manifestations of the disease, indicating the necessary specific diagnostic procedures. Only by description and recognition of the possible pathogenic agents, an adequate therapy can be initiated as described in the last chapter.

Aminoglycosides↗