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At least 109 records · Page 6Linked to original sources
PubMed1994

[An unusual cervical tumor: meningioma. Apropos of a case of petrous origin. Review of the literature of meningioma presenting as cervical mass].

Primary ectopic meningiomas are uncommon. The authors report a case of a 12-year-old boy with a meningioma presenting as a neck mass. The conclusion of the initial biopsy was chemodectoma, but on surgical resection, the tumour was found to have invaded the petrous bone. Post-operative follow-up was uneventful but magnetic resonance imagery revealed extension to the cerebello-pontine angle, the cavernous sinus, the tentorium and the falx. The authors discuss the main pathogenic hypotheses and the classification of ectopic meningiomas. Based on 62 similar cases reported in the literature, primary ectopic meningiomas are found most often in young subjects, with no female predominance, neurofibromatosis is often observed and angioblastic or malignant features are frequent. These tumours can be divided into 6 localizations (jugulo-carotid space, lymph nodes, parotid gland, thyroid gland, soft paravertebral tissues, skin) and into 3 pathogenic groups (solitary ectopic tumour of the neck, tumour of the neck connected to a cranial or spinal meningioma, metastasis). Meningioma of the jugulo-carotid space with connection to the skull base is the most frequent entity. Solitary ectopic meningiomas of the neck occur in only 1 out of 5 cases. In 2 out of 3 cases, the neck localization involves a connection to a cranial or spinal meningioma. In a few cases the neck mass is a metastasis. These findings suggest that a complete neuroradiological work-up is required. Prognosis depends on the completeness of the surgical resection and the histologic aggressiveness frequently encountered.

Child↗
PubMed1990

[Etiologic interpretation of acute intestinal diseases].

The authors suggest a scheme for the detection of the etiologic factor of an acute intestinal condition; this scheme permits detecting dysbiotic changes in the microbiocenosis, finding pathogenic or opportunistic microorganisms in fecal culture. Classification of acute intestinal diseases into those induced by pathogenic and opportunistic microorganisms, as well as those resultant from acute imbalance of the normal ratio of intestinal bacteria helps carry out differential therapy of patients. The results of such bacteriologic studies may be useful for epidemiologists.

Acute Disease↗
PubMed1993

Chronic fatigue syndrome: influence of histamine, hormones and electrolytes.

The chronic fatigue syndrome is poorly understood. We believe the underlying causes in many atopics and women are a persistent infection and hypersensitivity to the immune-suppressive effects of histamine and certain pathogens. We believe much to the symptomatology can be explained by all four types of hypersensitivity (Gell and Coombs classification) in reaction to a pathogen, electrolyte disturbances which include sometimes permanent changes in cell membranes' ability to pass electrolytes, sometimes permanent biochemical changes in mitochondrial function, and disturbances of insulin and T3-thyroid hormone functions. We also explain in detail what 'fatigue' means for these patients. We present evidence from the medical literature for the plausibility of our hypotheses.

Electrolytes↗
PubMed1988

Etiological agents of bovine mastitis.

A total of 137 microbial species, subspecies and serovars have been isolated from the bovine mammary gland. Nucleic acid hybridization studies have restructured the classification of many mastitis pathogens. Availability of defined species descriptions has permitted greater insight into the distribution and pathogenicity of many previously unrecognized microorganisms associated with bovine mastitis. Precise epidemiological studies are needed to better delineate the role of some microorganisms in bovine mastitis and to aid development of improved control methods.

Animals↗
PubMed1980

Classification of urinary tract infections by biotype identification of the pathogens.

Bacterial isolates from urinary tract infections were identified by biotyping. During a 2-year period all episodes of urinary tract infection in 276 patients from an office practice could be classified into 4 categories: 1) first or simple urinary tract infection, 2) recurrent urinary tract infection owing to unresolved bacteriuria during treatment, 3) recurrent urinary tract infection owing to bacterial persistence and 4) recurrent urinary tract infection owing to reinfection.

Adolescent↗
PubMed2001

Phenotypic and genetic characterization of NAD-dependent Pasteurellaceae from the respiratory tract of pigs and their possible pathogenetic importance.

Nicotinamide adenine dinucleotide (NAD)-dependent Pasteurellaceae other than Actinobacillus pleuropneumoniae and Haemophilus parasuis are frequently isolated from the respiratory tract of pigs. The taxonomic classification and relevance for pathogenicity of these bacteria deserves further attention. In the present study, 107 of these NAD-dependent isolates from the porcine respiratory tract, primarily from lungs with pathological changes, were investigated. On the basis of phenotypic criteria, such as haemolysis, urease, catalase, and indole formation as well as other fermentative activities, 50 of the isolates were assigned to Actinobacillus minor, 36 isolates to Actinobacillus porcinus and 21 isolates to Actinobacillus indolicus. However, many isolates among the three species showed fermentative activities differing from those of the respective type strain of the species. Serotyping on the basis of heat-stable polysaccharide antigens and 16 rDNA sequencing also revealed substantial heterogeneity within each of the three species although they clustered together in three distinct groups in the phylogenetic analysis. These three groups of NAD-dependent bacteria are different from, or in a borderline position, to the existing species or genera within the family Pasteurellaceae. A considerable number of isolates of these three groups were isolated in pure cultures from pneumonic lungs. Consequently, it will be necessary to critically review the opinion, that these NAD-dependent Pasteurellaceae are only "agents colonizing the mucosa". Further, taxonomic examinations of the strains within these three groups are indispensable to testing isolates for their virulence in gnotobiotic pigs.

Animals↗
PubMed1999

Characterization by numerical taxonomy and ribotyping of Vibrio splendidus biovar I and Vibrio scophthalmi strains associated with turbot cultures.

Twelve Vibrio strains were examined phenotypically in 91 biochemical characters and genotypically by ribotyping. Ten were isolated from sea water and two from diseased turbot (Scophthalmus maximus). All isolates originated from one experimental system located in Ría de Vigo (Galicia, north-west Spain). Different type strains were used for comparative purposes. The taxonomic position was analysed with the NTSYST-pc and similarities among strains were calculated by the Simple Matching coefficient (SSM). rRNA gene restriction patterns were performed with the HindIII enzyme. The SSM coefficient separated the 12 Vibrio strains into two groups which included strains that showed a SSM coefficient quite similar to V. splendidus biovar 1 (ATCC 33125) and V. scophthalmi (CECT 4638). None of 91 phenotypical characters were specific in distinguishing both species. The ribotyping confirmed the taxonomic classification of strains. The pathogenicity of each strain was evaluated; 10 environmental strains were avirulent and two, isolated from diseased turbot, were virulent. Different biotypes and ribotypes were found among the avirulent isolates. This work showed ribotyping to be a valuable tool for identification and confirmed the necessity of extending the ribotype database within closely related Vibrio species in order to clarify the taxonomic position.

Animals↗
PubMed1989

Comparative analysis of the genomes of intestinal spirochetes of human and animal origin.

The aim of the present work was to compare the genomes of 21 strains of intestinal spirochetes, which were isolated from patients suffering intestinal disorders, with those of Treponema hyodysenteriae (strain P18), the known etiological agent of swine dysentery (bloody scours), and of a nonpathogenic strain (M1) of Treponema innocens. The percent guanine-plus-cytosine value of the 23 DNAs was found to be 25.5 to 30.1, as determined by a double-labeling procedure based on nick-translation by DNA polymerase I. The genome size of two spirochetal strains, of human and porcine origin, was found to be similar (4 x 10(6) base pairs) and close to that of the reference bacterium Escherichia coli (4.2 x 10(6) base pairs). Restriction analysis showed the presence of two modified bases in spirochetal DNA. Methyladenine was present in the GATC sequence of DNA from 15 spirochetes of human origin, and methylcytosine was present in several sequences occurring in all strains. The DNA of T. hyodysenteriae displayed a 30 to 100% homology with respect to that of 21 spirochetes from humans, thus suggesting the occurrence of a genetic heterogeneity in the latter group. These data indicate that the intestinal spirochetes analyzed in the present work are related; hence there is a possibility of domestic animals being reservoirs of microorganisms pathogenic for humans. A classification of intestinal treponemes into subgroups has been proposed on the basis of restriction analysis and hybridization experiments.

Animals↗
PubMed1979

Numerical classification of Yersinia enterocolitica and relationship between its subdivision and pathogenicity.

A total of 102 strains of Yersinia enterocolitica were studied on their morphology, physiology and biochemistry at 25 degrees C. All data coded in binary notation and similarities between each pair of strains by simple matching coefficient were calculated using subsequent computation. Four clusters were distinguished within the 102 strains at a similarity level of 90--93%. Although some discrepancies were recognized on reactions of indole, xylose, esculin and salicin, it was evident that 3 of the 4 groups in the present study correspond to the DNA relatedness groups of Brenner et al., respectively. On the other hand, it was confirmed, using feeding tests with monkeys, that only the group 1 was enteropathogenic. These results support the suggestion of Brenner et al. that their DNA relatedness group 1 is true Y. enterocolitica.

Animals↗
PubMed1992

Evolutionary relationships of a plant-pathogenic mycoplasmalike organism and Acholeplasma laidlawii deduced from two ribosomal protein gene sequences.

The families within the class Mollicutes are distinguished by their morphologies, nutritional requirements, and abilities to metabolize certain compounds. Biosystematic classification of the plant-pathogenic mycoplasmalike organisms (MLOs) has been difficult because these organisms have not been cultured in vitro, and hence their nutritional requirements have not been determined nor have physiological characterizations been possible. To investigate the evolutionary relationship of the MLOs to other members of the class Mollicutes, a segment of a ribosomal protein operon was cloned and sequenced from an aster yellows-type MLO which is pathogenic for members of the genus Oenothera and from Acholeplasma laidlawii. The deduced amino acid sequence data from the rpl22 and rps3 genes indicate that the MLOs are more closely related to A. laidlawii than to animal mycoplasmas, confirming previous results from 16S rRNA sequence comparisons. This conclusion is also supported by the finding that the UGA codon is not read as a tryptophan codon in the MLO and A. laidlawii, in contrast to its usage in Mycoplasma capricolum.

Acholeplasma laidlawii↗
PubMed1985

Limitations and problems of diabetes classification from an epidemiological point of view.

There are residual ambiguities between the two main current glycaemic definitions of the categories of DM, IGT and normal GT which should be resolved. IGT is clearly a highly heterogeneous category and could with advantage be resolved into its identifiable subsets though adequate data for this is not yet available. The concept of insulin dependency requires clearer definition for operational purposes. Biochemical parameters (e.g. C-peptide responses) may help. Attempts to combine clinical manifestations and pathogenic mechanisms in a single classification (e.g. IDDM/NIDD versus Type I/Type II) should be handled with care. If the term Type I is to be retained, it should be applied to a defined pathogenic process, not to a clinical type of DM. The term Type II is inadequately defined at present. IDDM and NIDDM, clinical descriptive terms, may be provoked by a variety of pathogenic mechanisms (i.e. they are 'heterogeneous'). They could be subclassified by mechanism (when known). More visibility should be given in classification to non-Europid forms of DM (e.g. 'Tropical or 'Nutritional' DM). A staging dimension should be recognised in classifications of DM. Future classifications will benefit from the incorporation of the presence or absence of susceptibility/resistance factors to diabetes itself or to its severe long term sequelae. There remain uncertainties about the definitions and clinical implications of gestational DM (and gestational IGT) not discussed above. It should be accepted that different user groups may need different subclassification of diabetes and glucose intolerance to meet their specific requirements and so long as this is made clear and definitions are adequate this should not be a problem. However, for the present, all groups should accept the proposed glycaemic definitions of DM or IGT for the purposes of comparability.

Adult↗
PubMed2026

Spatiotemporal patterns of Rift Valley fever virus in Africa: a retrospective genomic epidemiology and phylodynamic modelling study.

BACKGROUND: Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing outbreaks in humans and ruminants across Africa and the Arabian Peninsula. Originally restricted to the Great Rift Valley, RVFV has expanded geographically, prompting its classification by WHO as a pathogen of pandemic potential. We investigated the evolutionary and spatial dynamics of RVFV across Africa. METHODS: We used genomic data generated at the International Livestock Research Institute Nairobi genomic laboratory (BioProject PRJNA1106221) and combined with publicly available datasets retrieved from the National Center for Biotechnology (NCBI) GenBank nucleotide database. In retrieving RVFV genome sequences from the NCBI GenBank, we applied the search terms "Rift Valley fever virus segment L AND 6404[SLEN]", "Rift Valley fever virus segment M AND 3885[SLEN]", and "Rift Valley fever virus segment S AND 1520:1690[SLEN]" for L (Large), M (Medium), and S (Small) segments, respectively. For sequences without additional spatiotemporal information, we searched PubMed to extract the associated sequence metadata. We performed molecular clock analysis, phylogenetic inference, phylodynamic modelling (continuous phylogeographic reconstruction), and landscape phylogeography on the three RVFV genome segments (L, M, and S). We aimed to assess evolutionary rates, dispersal patterns, and environmental drivers. Focus was placed on lineage C, the most widely distributed variant. FINDINGS: The global dataset used in this study consisted of large (n=236), medium (n=237), and small (n=247), which were further filtered to exclude potential reassortants and vaccine strains. Genome sequences retrieved from NCBI GenBank database comprised large (n=180), medium (n=184), and small (n=202). The genome sequences from retrospective human and livestock isolates comprised large (n=56), medium (n=53), and small (n=45) collected in Burundi (2018), Kenya (2007, 2018, 2019, 2021, and 2022), and Rwanda (2018 and 2022). Our dataset revealed that RVFV exhibited low overall genetic diversity. Lineage C, however, showed evidence of active evolution, with substitution rates ranging from 3·58 × 10-4 to 9·76 × 10-4 substitutions per site per year. This lineage probably originated in Zimbabwe in the mid-1970s and has since expanded across eastern and southern Africa. Phylogeographic reconstructions revealed rapid spread, with diffusion coefficients exceeding 50 000 km2 per year. INTERPRETATION: Lineage C appears capable of establishing endemic transmission in new regions, with ongoing diversification observed during interepidemic periods. These observations reinforce the value of continuous genomic surveillance, particularly during cryptic transmission phases when adaptive mutations might emerge. Although further evidence is needed, observed trends in climate variability and land-use change point to the potential benefit of targeted surveillance in settings that could be at increased risk, including urban centres and wetlands. FUNDING: This work was supported by the German Federal Ministry for Economic Cooperation and Development, the Rockefeller Foundation, and the Africa Centres for Disease Control and Prevention.

Rift Valley fever virus↗
PubMed2000

[Mechanisms of persistence in bacterial pathogens].

This paper gives an original classification of persistent bacterial mechanisms, that is based on the protection (isolation) of peptidoglycan, by recognizing the host immune system. The classification includes a bacterial cell wall screening and production of secreted agents, inactivating host defense, as well as antigenic mimicry, and bacterial wall-free formations (L forms). A group of novel bacterial secreted agents by suppressing host defense is described.

Animals↗
PubMed2026

The Animal Variant Classification Guidelines v2: An Update With New Criteria and Improved Clarifications.

The Animal Variant Classification Guidelines (AVCG) were developed to standardize and objectify the classification of putative disease-causing variants. These guidelines are sufficiently reproducible and are used to classify previously published and new disease-causing variants across species. Here, the guidelines are updated (AVCG.v2), based on a three-phase decision process. Overall, four new criteria and seven clarifying comments were added. The number of criteria has increased from 23 to 27, with three new criteria supporting pathogenicity and one new criterion supporting benign classification. Pharmacogenomic variants were determined to fall within the scope of the guidelines. These updated guidelines are being used by the Variant Pathogenicity Working Group (VPWG), part of the Animal Genetic Testing Standardization standing committee, which is a committee of elected members of the International Society for Animal Genetics (ISAG). Under the auspices of ISAG, the VPWG retrospectively classifies published putative disease-causing variants. The pathogenicity label for a variant will be presented in the variant tables of Online Mendelian Inheritance in Animals (OMIA; https://omia.org/). The AVCGv.2 criteria and recommendations were developed by the expertise of the animal genetics community and the ISAG Executive Committee through the Animal Genetics Testing Standardization Committee endorses and strongly encourages their use to evaluate the evidence supporting pathogenicity of putative disease-causing variants.

Animals↗
PubMed1997

Classification of human and animal strains of Fusobacterium necrophorum by their pathogenic effects in mice.

Forty-six strains of Fusobacterium necrophorum, 24 from animals and 22 of human origin, were examined by pathogenicity tests in mice, while the same strains were being examined in laboratories elsewhere by other methods. The pathogenicity tests consisted of (1) subcutaneous inoculation with a large dose of a pure culture, (2) subcutaneous inoculation with a small dose of F. necrophorum mixed with a large but relatively harmless dose of Staphylococcus aureus, and (3) intravenous inoculation with a large dose of a pure culture. Fourteen strains, all of animal origin, showed the characteristic behaviour of biotype A. Twenty-eight strains, 10 of animal origin and 18 from man, were classified as biotype B. The remaining four strains, all from man, produced a distinct type of infection in mice; these strains were referred to as 'A2433-like' because of their resemblance to a strain described in an earlier study. It would appear that biotype A strains, responsible for classical necrobacillosis in animals, do not infect man; that biotype B strains occur in both man and animals; and that 'A2433-like' strains are probably confined to man.

Animals↗
PubMed2026

Exploring shotgun metagenomic data to detect microeukaryotic pathogens in wildlife.

BACKGROUND: Microeukaryotic parasites of the intestinal tract are an understudied group of organisms that infect humans and many other animals. Targeted sequencing methods focused on individual loci are usually employed for detection of these parasites, making comprehensive studies of microeukaryotic parasite diversity within hosts or other systems difficult. Exploratory approaches such as shotgun metagenomic sequencing to survey the diversity of microeukaryotic parasites in new and existing datasets are not well developed. RESULTS: Utilizing existing datasets from 12 goose fecal samples, we explored some of the benefits and challenges of using shotgun metagenome sequencing to detect microeukaryotic parasites. We demonstrated the importance of careful curation of read classification data to avoid erroneously linking pathogens to hosts or environments as unsupported classifications were common in the data and varied widely depending on analysis parameters. However, we were able to establish strong support for the presence of sequences of Eimeria and Enterocytozoon bieneusi. In addition, examination of trichomonad reads indicated that parasite reads mapping to human pathogens unlikely to colonize geese may in fact represent cryptic microeukaryotic species that are not included in existing curated databases opening new potential avenues of study. CONCLUSIONS: Taken together these findings support the idea that exploring microeukaryotic parasite diversity within shotgun metagenomic datasets can be beneficial to our understanding of the presence and diversity of these organisms in wildlife hosts.

Animals↗
PubMed2026

RNA splicing evidence enables robust classification of BRCA1 exon 18 variants: Results from the ENIGMA consortium.

The Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) research consortium conducted a comprehensive study to characterize spliceogenic variants in BRCA1 exon 18. The absence of systematic RNA-based assessment for these variants has led to inconsistent interpretation, limiting accurate classification and management of individuals and their families. The splicing profile of 166 variants was assessed using minigene assays; 32 were additionally analyzed in blood-derived RNA from 51 individuals and 18 in mouse embryonic stem cell (mESC)-based assays to evaluate homology-directed repair (HDR) capacity. mRNA assessment by RT-PCR in blood samples and minigene assays showed a significant positive correlation, with splicing analysis in mESCs displaying highly concordant results. The mESC-based HDR assay showed that the in-frame exon 18 skipping (&#x394;18) transcript encodes a non-functional protein lacking rescue activity. Linear regression analysis using mESC splicing and functional data indicated that &#x2265;59% of full-length (FL) levels and <34% of &#x394;18 were associated with benign HDR activity. These thresholds differ from those recommended by the ClinGen ENIGMA BRCA1 and BRCA2 Variant Curation Expert Panel American College of Medical Genetics and Genomics (ACMG)/Association for Molecular Pathology (AMP) specifications for applying BP7_strong(RNA): >30% functional transcripts or <70% non-functional transcripts. Incorporation of RNA splicing evidence into variant interpretation increased pathogenic (28.6%-31.7%) and benign (3.7%-24.4%) classifications while reducing likely pathogenic (19.5%-17.7%), uncertain (18.9%-8.5%), and likely benign (29.3%-17.7%) categories. Experimental mRNA profiling impacted the interpretation of 34% of variants and resolved uncertainty in approximately 10% of cases. Exon 18 skipping was less tolerated, indicating that the degree of splice perturbation required to impair BRCA1 function may depend on the nature of the resulting non-functional transcript.

Humans↗
PubMed1997

Identification of pathogenic yeasts of the imperfect genus Candida by polymerase chain reaction fingerprinting.

With the increase in the number of immunocompromised hosts, the number of fungal pathogens has increased markedly. Identification and classification, especially of yeast species and strains, is often difficult when based solely on phenotypic characteristics. Since it became clear that different fungal pathogens require specific treatment strategies, there is a need for simple, rapid and reliable methods to identify fungal isolates. Polymerase chain reaction (PCR) fingerprinting was successfully applied here to identify yeast isolates. Microsatellite [(GTG)5; (GACA)4] and minisatellite [(5'GAGGGTGGCGGTTCT 3'), derived from the core-sequence of the phage M13] specific primers were used as single primers in the PCR to amplify hypervariable interrepeat DNA sequences from over 200 European, American and Australian clinical isolates within the genus Candida. Each species, represented by its type strain, could be identified by a specific multilocus pattern, allowing for the assignment of all the isolates to the appropriate species. Intra-species variation in the multilocus profiles was about 20% compared to inter-species variation, which was up to 80%. Anamorph-teleomorph pairs could be identified by highly homologous PCR fingerprint patterns. PCR fingerprinting was more discriminatory when compared with routinely used biochemical tests (Vitek YBC and API ID 32C). PCR fingerprinting has proven to be a powerful tool for the identification of medically important yeasts. It is rapid, sensitive, reliable, highly reproducible, stable in vitro and in vivo, and applicable to large scale experiments. Potential applications include: yeast taxonomy, epidemiology, environmental surveys, and improvement of the diagnosis of mycotic diseases.

Australia↗