Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “pathogenicity classification”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMed1975

Nucleic acid content and nucleotide composition of DNA in leptospirae.

The contents of DNA and RNA were studied in 9 strains of leptospirae and the composition of nitrogen bases of DNA in 20 strains of pathogenic and saprophytic leptospirae. It has been found that leptospirae contain a high per cent ration of nucleic acids. According to the nucleotide composition, the family of Leptospira as a whole belongs to the AT-type. According to overall guanine and cytosine contents, the investigated strains of pathogenic leptospirae fall into 3 groups and differ from the seprophytic strains. With respect to the limited number of the investigated strains, the DNA nucleotide composition of leptospirae can be used as a supplementary biochemical criterion in the classification of leptospirae.

Chromatography, Paper↗
PubMed2005

Association of genetic variability within the Borrelia burgdorferi sensu lato with the ecology, epidemiology of Lyme borreliosis in Europe.

Lyme borreliosis (LB) represents the most common vector-borne zoonotic disease in the Northern Hemisphere. The infection is caused by the spirochetes of the Borrelia burgdorferi sensu lato (s.l.) complex which circulate between tick vectors and vertebrate reservoir hosts. The complex of Borrelia burgdorferi s.l. encompasses at least 12 species. Genetic variability within and between each species has a considerable impact on pathogenicity, clinical picture, diagnostic methods, transmission mechanisms and its ecology. The distribution of distinct genospecies varies with the different geographic area and over a time. In recent years, new molecular assays have been developed for direct detection and classification of different Borrelia strains. Profound studies of strain heterogeneity initiated a new approach to vaccine development and routine diagnosis of Lyme borreliosis in Europe. Although great progress has been made in characterization of the organism, the present knowledge of ecology and epidemiology of B. burgdorferi s.l. is still incomplete. Further information on the distribution of different Borrelia species and subspecies in their natural reservoir hosts and vectors is needed.

Animals↗
PubMedDate not supplied

Pathogenetic interrelations between cholesterolosis and cholesterol gallstone disease.

In order to define the relationship between cholesterolosis (COL) and cholesterol gallstone disease (CGD), risk factors were comparatively investigated in a great number of patients. Sex, age and metabolic risk factors were the same for both diseases, but gallbladder anomalies and neuroendocrine disturbances were more often associated with COL. The lipid composition of the gallbladder bile was determined in patients with COL. The bile acid decrease and the increase of cholesterol molar concentration (moles %) were found, similar to those known in CGD. The similarity of risk factors and of bile lithogenicity, as well as the frequent association of COL and CGD suggest a pathogenic relationship of both diseases. Local morphological changes in conditions of high biliary cholesterol levels may be responsible for the intraparietal precipitation of cholesterol in COL. Thus, COL seem to be a peculiar variant of CGD and its classification into the heterogeneous group of cholecystoses is at present questionable.

Adult↗
PubMed2026

Whole-genome characterization and phylogenetic placement of Fusarium oxysporum f. sp. vasinfectum isolates.

Fusarium wilt of cotton, caused by Fusarium oxysporum f. sp. vasinfectum (Fov), remains a persistent threat to cotton production worldwide. Among the known races, Fov race 4 and its extra-virulent variants cause particularly severe losses in Upland cotton. Although several Fov genome assemblies have been assigned to races, the genomic diversity and evolutionary relationships among pathogenic and non-pathogenic isolates associated with cotton outbreaks remain poorly understood at the whole-genome level. This study addressed these gaps by generating and comparing high-quality genome assemblies of four Fusarium isolates collected from Texas cotton fields: two pathogenic (TX17-24 and TX18-9) and two non-pathogenic (TX17-6 and TX18-6). Draft assemblies were generated using Oxford Nanopore long reads and polished with Illumina reads. Comparative genomic analyses showed that pathogenic isolates possessed larger genomes and more conserved orthologous families, whereas non-pathogenic isolates contained more unique genes. Analyses of predicted secreted effectors, transposable elements, and carbohydrate-active enzymes further distinguished pathogenic and non-pathogenic lineages, suggesting roles in virulence adaptation and genome plasticity. Phylogenomic analyses using k-mer-based, assembly- and alignment-free methods incorporated all available long-read Fov genomes and revealed substantial genetic diversity within races 1 and 4, clustering isolates into multiple sublineages. These findings show that Fov race diversification is underestimated when based on traditional classification schemes and may be shaped by host specialization, geographic separation, or horizontal gene transfer. This work advances our understanding of the genomic diversity and evolutionary dynamics of Fov and establishes a foundation for improved race identification and characterization of Fusarium wilt pathogenesis in cotton.

Fusarium oxysporum↗
PubMed1976

Classification of hyperlipidaemias - a time for review?

Evidence is presented to show that the classical diagnosis of disturbances in lipid metabolism in terms of lipoprotein phenotypes should now be replaced by a more simple one based on evaluation of plasma lipids alone. This is because of the chemical heterogeneity of the lipoproteins, the clinical, biochemical, pathogenic and genetic heterogeneity of hyperlipoproteinaemias, and the questionable value of 'typing' of the secondary disorders.

Apoproteins↗
PubMed1998

Alzheimer's disease and Parkinson's disease: distinct entities or extremes of a spectrum of neurodegeneration?

Alzheimer's disease (AD) and Parkinson's disease (PD) are generally considered to be separate and distinct disease entities. However, a considerable amount of evidence demonstrates that these disorders share common clinical and neuropathologic features and that overlap between the two conditions is extensive. For example, a significant percentage of AD patients exhibit extrapyramidal features, and many PD patients develop dementia. Similarly, at autopsy many AD patients not only exhibit the neuropathologic features of that disorder but also exhibit nigral pathology, including Lewy bodies. The vast majority of demented PD patients show widespread neurofibrillary tangles and senile plaques as well as Lewy body formation and nigral degeneration. The extent of such overlap is far greater than one would anticipate by chance alone. We argue that such overlap reflects a common pathogenic mechanism for the neurodegeneration encountered within specific vulnerable neuronal populations. Furthermore, we suggest that the current nosologic approach, which attempts to separate AD from PD, fails to properly deal with the issue of overlap and that a new classification of the neurodegenerative disorders should be considered.

Alzheimer Disease↗
PubMedDate not supplied

Pyrolysis mass spectrometry characterisation and numerical taxonomy of Aeromonas spp.

Reference strains (2) and 29 isolates of Aeromonas spp. from clinical material and environmental specimens were characterised in traditional biochemical tests, and in pyrolysis mass spectrometry, which gives data reflecting whole-cell composition. Numerical taxonomic analyses of the data sets were compared with conventional identification at species level, and pathogenic potential, as inferred from the origin of the isolates. Clustering with conventional test reaction patterns showed, for each of the species represented, a clearly defined core group of 'typical' isolates, surrounded by a halo of aberrant strains. One further cluster comprised strains intermediate between A. caviae and A. hydrophila, and one strain was grossly atypical in both analyses. Clustering from pyrolysis data corresponded less well with species identification. Broadly, the biochemical division between core and halo strains was supported in pyrolysis for A. caviae and A. sobria, but the main group of A. hydrophila in pyrolysis comprised strains clustering in the core and halo groups of this species, and three strains intermediate between A. hydrophila and A. caviae in biochemical tests. Two further pyrolysis clusters comprised core and halo strains of A. hydrophila. However, pyrolysis clustering correlated well with inferred pathogenicity, showing four clusters of probable pathogens, six clusters of probable non-pathogens, and one two member cluster of doubtful status. Most strains that clustered in the species haloes, or in species-intermediate groups in biochemical tests, were non-human isolates, or were isolated in the absence of symptomatic infection. The correlation of inferred pathogenicity with biochemical clustering was poorer than that with pyrolysis clustering.

Aeromonas↗
PubMed2005

A study on symptom profiles of late-life depression: the influence of vascular, degenerative and inflammatory risk-indicators.

BACKGROUND: If specific symptom profiles of depressive disorders in the elderly are related to a specific etiology, this could have implications for everyday clinical practice. We hypothesized that a "motivational" profile, with symptoms such as psychomotor change, loss of interest and loss of energy, could clinically separate patients with predominantly vascular or degenerative risk indicators from patients with inflammatory risk indicators. METHODS: A total of 4051 subjects participated in a study on mental health problems in community-dwelling elderly. Information on psychiatric symptoms, demographic and medical status, previous history and family history was obtained. We distinguished three subgroups according to predominant somatic risk-indicators; vascular, degenerative and inflammatory groups. RESULTS: Motivational symptoms were associated with vascular or degenerative risk-indicators for depression; psychomotor change with both indicators; loss of energy with vascular, though also with the inflammatory indicator, and thinking/concentration disturbance with the degenerative indicator. The so-called mood symptoms of depression, especially thoughts of death, were more strongly related with the inflammatory risk-indicator. Melancholic symptoms like appetite and sleep disturbances were more strongly associated with the inflammatory risk-indicator. LIMITATIONS: Etiological classification was not confirmed by additional investigations such as laboratory findings or MRI brain scans. CONCLUSION: This study showed that in patients with a late-life depression specific symptoms of the depressive disorder may reflect the predominant underlying pathogenic mechanism.

Age of Onset↗
PubMed1965

ERWINIA-LIKE MICROORGANISMS ISOLATED FROM ANIMAL AND HUMAN HOSTS.

Erwinia-like microorganisms were isolated from the vital organs of more than 40% of a large deer population examined as well as from 13% of a small random sampling. Over a brief period of observation, a similar isolate was recovered from throat cultures of two children and one adolescent. There is no obvious explanation of the presence of the plant pathogen or its significance under these circumstances.

Adolescent↗
PubMed1998

Comparative genome analysis of Bacillus sphaericus by ribotyping, M13 hybridization, and M13 polymerase chain reaction fingerprinting.

A comparative genome analysis of 15 strains representing the five homology groups of the highly heterogeneous species Bacillus sphaericus was performed by M13 hybridization fingerprinting, M13 polymerase chain reaction fingerprinting, and ribotyping with the whole rrn operon. The computer cluster analyses of the polymorphic patterns, presented in dendrograms, showed that these methods allow the differentiation of the individual strains and some homology groups. Our results confirm the close genetic relatedness of the mosquito pathogenic strains of group IIA and support the idea for differentiation of a separate species. At the same time, we present additional proof of the significant genetic heterogeneity of B. sphaericus and the necessity of reconsideration of its present classification.

Bacillus↗
PubMed2006

Epidemiology, etiology and pathophysiology of traveler's diarrhea.

Traveler's diarrhea (TD) is the most frequent health problem in travelers to developing countries. Several personal and environmental risk factors are at the basis of TD acquisition and are discussed in this paper. TD is caused by a wide range of infectious organisms, ETEC and EAEC bacteria strains being the main enteropathogens incriminated in TD. Other causative bacteria are: Shigella spp., Campylobacter spp., Vibrio spp., Aeromonas spp., Salmonella spp., and Plesiomonas spp. Parasite species are also included: Cyclospora cayetanensis, Giardia lamblia, Cryptosporidium, Entamoeba histolytica, as well as viruses: rotavirus, adenovirus, Norwalk virus. Due to the great diversity of pathogens incriminated, several pathophysiological mechanisms have been described and some of them are still poorly understood. The clinical symptoms present are also quite variable, although inflammatory and non-inflammatory diarrhea have been established as a classical and basic classification of diarrhea.

Bacteria↗
PubMed2005

Survival of clostridium perfringens during simulated transport and stability of some plasmid-borne toxin genes under aerobic conditions.

Clostridium perfringens is a pathogen of great concern in veterinary medicine, because it causes enteric diseases and different types of toxaemias in domesticated animals. It is important that bacteria in tissue samples, which have been collected in the field, survive and for the classification of C. perfringens into the correct toxin group, it is crucial that plasmid-borne genes are not lost during transportation or in the diagnostic laboratory. The objectives of this study were to investigate the survival of C. perfringens in a simulated transport of field samples and to determine the stability of the plasmid-borne toxin genes cpb1 and etx after storage at room temperature and at 4 degrees C. Stability of the plasmid-borne genes cpb1 and etx of C. perfringens CCUG 2035, and cpb2 from C. perfringens CIP 106526, JF 2255 and 6 field isolates in aerobic atmosphere was also studied. Survival of C. perfringens was similar in all experiments. The cpbl and etx genes were detected in all isolates from samples stored either at room temperature or at 4 degrees C for 24-44 h. Repeated aerobic treatment of C. perfringens CCUG 2035 and CIP 106526 did not result in the loss of the plasmid-borne genes cpb1, cpb2 or etx. Plasmid-borne genes in C. perfringens were found to be more stable than generally reported. Therefore, C. perfringens toxinotyping by PCR can be performed reliably, as the risk of plasmid loss seems to be a minor problem.

Clostridium perfringens↗
PubMed1993

Sepsis-bacteraemia and other infections due to non-opportunistic bacterial pathogens in a consecutive series of 788 patients hospitalized for HIV infection.

A retrospective study was carried out to evaluate the incidence, etiology and role of non-opportunistic bacterial infections in a series of 788 consecutive HIV-infected patients hospitalized during the last 7 years; 71.9% of patients were i.v. drug addicts, 15.6% homo-bisexual men, 7.4% heterosexuals, 2.7% haemophiliacs and 2.4% children with vertically-acquired infection. According to the CDC classification of HIV infection, 71 patients were classified as CDC I-II, 148 as CDC III, and 569 (72.2%) as CDC IV. Diagnosis of bacterial infection was based on signs and symptoms, in association with the isolation of microorganisms consistent with the clinical picture. Two hundred and nineteen patients out of 788 (27.8%) (4 in CDC group I-II, 34 in CDC III and 181 in CDC IV), presented one or more episodes of non-opportunistic bacterial infection. The morbidity of these infections showed a significant correlation with the progression of HIV disease (CDC III vs. CDC I-II [p < 0.003] and CDC IV vs. CDC III [p < 0.05]), but no significant relation was found with age, sex or type of risk for HIV infection. The most frequent clinical picture was sepsis/bacteraemia (33.3%), followed by respiratory tract (23.8%), and genitourinary tract (20.8%) infections. A total of 399 bacterial pathogens were isolated in 303 different episodes of infection: 211 (52.9%) were gram-positive and 188 gram-negative, with Staphylococcus aureus (69 isolations), Staphylococcus epidermidis (50), and Pseudomonas spp. (48) as the major pathogens. Sepsis/bacteraemia was the most frequent clinical picture associated with growth of gram-positive pathogens, while detection of gram-negative bacteria appeared more significantly related with genitourinary or respiratory tract localizations. Bacterial infections in hospitalized HIV-infected patients, even though rarely life-threatening, need particular attention because of the high incidence and recurrence rate, the wide aetiological and clinical spectrum, the frequent microbial associations and the strict relationship with the progression of HIV disease.

Adolescent↗
PubMed1984

[Classification and pathogenesis of cutaneous paraneoplastic syndromes].

The associations between skin conditions and malignant tumours are reviewed and classified in two groups: indirect associations (predisposing genetic factor or carcinogenic agent), and direct associations with parallel evolutions corresponding to the true paraneoplastic syndromes. Occasional associations are also mentioned. The cutaneous paraneoplastic syndromes can be classified according to their pathogenic mechanisms, although these are mostly hypothetical, allowing those of secretory, immunological, deficient and neurovascular origins to be distinguished.

Acanthosis Nigricans↗
PubMed1995

Splenectomy as part of cytoreductive surgery for ovarian carcinoma.

Splenectomy is sometimes necessary to achieve optimal cytoreduction or manage iatrogenic injury in the surgical management of epithelial ovarian cancer (EOC) and related conditions. To determine the place of splenectomy in cytoreductive surgery a retrospective review was made of patient hospital records. Between April 1989 and August 1994, 18 patients were found to have undergone a splenectomy as a component of their surgery leading to optimal debulking. Morbidity attributable to the splenectomy was minimal, with no significant increase in operative time or blood loss. The morbidity attributable to the splenectomy was as follows: atelectasis and/or effusion (8), pancreatic tail injury (4), thrombocytosis > 10(6)/microliters (3), pancreatic pseudocyst (1), partial left adrenalectomy (1), and pulmonary embolism (1). There were no instances of overwhelming postsplenectomy infection. Five patients were anticipated to require splenectomy and may have benefitted from preoperative vaccination against potential pathogens. Three patients were found to have splenic parenchymal metastases. Consistent with the international literature, these patients had other features consistent with stage IV disease, recurrent disease, or poor survival. Consideration should be given to expanding the FIGO stage IV classification to include splenic parenchymal disease. Splenectomy is a feasible and safe procedure to facilitate optimal tumor debulking; however, the potential associated morbidity mitigates against this procedure if significant, suboptimal residual disease is left elsewhere.

Adult↗
PubMed2006

A new parasite that infects eggs of the mud crab, Scylla serrata, in Australia.

The mud crab, Scylla serrata, is currently being evaluated for its feasibility for mass aquaculture in Australia. As part of the evaluation process, pathogens that can affect this species need to be identified. This research note describes a possible new parasite that infects the eggs of S. serrata. The parasite was discovered in two separate cases (three months apart) in a broodstock research program and appears to cause 100% egg mortality. The parasite consists of a cluster of cells with rhizoids that appear to function as an anchorage and a feeding organ. The individual cells range from 3 to 6 microm with a single nucleus. The parasite could not be classified to a phylum by morphology alone. However, BLAST analysis of the DNA sequence from a PCR amplicon generated using universal 18S ribosomal RNA gene primers indicated similarity to pathogenic thraustochytrids, Dermocystidium sp. and Rhinosporidium seeberi. All except R. seeberi are protistan parasites of fish and crustaceans. A neighbour-joining phylogenetic tree confirmed the homology with the thraustochytrids; however, further molecular techniques need to be exploited for absolute classification of this new parasite.

Animals↗
PubMed2026

An Integrative Morphological and Genomic Analysis With a Refined Fluorescence In Situ Hybridization (FISH) Threshold and Novel Kinase Fusions in a Large Asian Cohort of Spitzoid Neoplasms.

Differentiating atypical Spitz tumors (ASTs) from true Spitz melanomas (SMs) and conventional melanomas with spitzoid features (MSFs) remains a formidable diagnostic challenge. Because current molecular epidemiological data are overwhelmingly derived from Caucasian cohorts, the genomic landscape of Asian populations remains largely unexplored. To elucidate the molecular progression landscape and refine the diagnostic criteria, we performed a comprehensive multimodal analysis-integrating histomorphology, immunohistochemistry, multiprobe fluorescence in situ hybridization (FISH), and targeted RNA/DNA-based next-generation sequencing (NGS)-on a cohort of 140 spitzoid neoplasms. This cohort, comprising 126 ASTs, 8 SMs, and 6 MSFs, represents the largest Asian cohort to date. Malignant phenotype strongly correlated with lesional asymmetry, deep atypical mitoses, a sheet-like growth pattern, diffuse preferentially expressed antigen of melanoma positivity, and significant loss of p16 expression (64.3% in SM/MSF vs 9.5% in ASTs; P < .0001). Building upon the established melanoma FISH criteria, we optimized a prognostic threshold of &#x2265;2 FISH abnormalities specifically tailored for spitzoid neoplasms. We demonstrated that isolated single chromosomal aberrations (particularly MYB loss) are relatively stable events that are frequent in indolent ASTs, whereas our refined &#x2265;2 threshold yielded 100% sensitivity and 92.5% specificity for predicting regional lymph node metastasis/local recurrence. Molecularly, NGS identified mutually exclusive initiating driver alterations (comprising kinase fusions and HRAS mutations) in 89.9% of true Spitz neoplasms, a remarkably high prevalence suggesting a distinct genetic background in Asian populations. We also characterized 5 entirely novel kinase fusions (ZNF24::ROS1, PCBP1::ROS1, NUMA1::RET, CBWD1::ALK, and TPR::NTRK1). Furthermore, NGS definitively segregated true Spitz neoplasms from morphological mimics (MSF), which lacked fusions and were driven by canonical genomic alterations of the conventional melanoma pathway. Integrating these genomic landscapes validated a stepwise progression model. Although isolated kinase fusions drove indolent ASTs, malignant SM invariably harbored concurrent pathogenic secondary alterations, demonstrating a profound reliance on CDKN2A/B, TP53, and CDK4 aberrations. Ultimately, we propose an integrated diagnostic algorithm combining morphological evaluation, the refined FISH threshold, and comprehensive NGS profiling, providing a precise, evidence-based framework for pathway classification and clinical management of spitzoid neoplasms.

fluorescence in situ hybridization↗