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PubMedDate not supplied

[Geometry and algebra of branches of the middle cerebral artery].

A classification of the cortical branches of the middle cerebral artery (MCA) is suggested by means of which each branch in any hemisphere can be qualified and identified in any variant of MCA branching. The principle of the classification consists in grouping the branches into arteries and trunks of the second, third, etc. order. Branches supplying blood to a certain sector of the lateral surface of the hemisphere are designated arteries. Their number and zone of branching are constant. Branches giving rise to 2 and more arteries are named trunks. Branching of the trunks, the number of trunks of the second, third, etc. order, and the site and type of origin of the arteries are extremely variable. Each trunk can be designated by a formula stating its order and the name of the artery supplied by this trunk. The arrangement of the MCA branches on the surface of the gyri and deep in the sulci, represented on the map of the lateral surface of the hemisphere, is designated conditionally as geometry of MCA branches. The order of branching of the trunks and the type of origin of the arteries, represented on abstract maps of the lateral surface of the hemisphere, are designated conditionally as algebra of the MCA branches. The variability of the geometry and algebra of the MCA branches must be taken into consideration in operations for extra-intracranial microanastomosis and in endovasal intervention on the MCA.

Cerebral Arteries↗

PubMedDate not supplied

[Subdivision of certain morphological variants of chronic glomerulonephritis].

Modern methods allow to detail morphological classification of chronic glomerulonephritis, to adapt it to the clinical classification and to recommend it for practical use. This specification concerns minimal changes and a group of mesangial chronic glomerulonephritis. The term "minimal changes" is a light-microscopic definition and covers rather a heterogeneous group of diseases or their initial manifestations. Differential diagnosis of these diseases is feasible only at the electron microscopic level. A group of chronic glomerulonephritis (mesangioproliferative and mesangiocapillary) includes variants distinguished on the basis of immunohistochemical, light microscopic and electron microscopic methods. Of them, the immunohistochemical method is most valuable for differentiation of mesangioproliferative glomerulonephritis.

Chronic Disease↗

PubMed2001

Topological polymer chemistry: systematic classification of nonlinear polymer topologies.

Nonlinear polymer topologies composed of cyclic and branched polymer segments are systematically classified by reference to constitutional isomerism in a series of alkanes (CnH2n+2), monocycloalkanes (CnH2n), and polycycloalkanes (CnH2n-2, CnH2n-4, etc). Thus, the total number of chain ends (termini) and of branch points (junctions) are maintained as invariant parameters, as well as the number of branches at each junction and the connectivity of junction. On the other hand, the distance between two adjacent junctions and that between the junction and terminus are taken as variant parameters. On the basis of the classification of polymer topologies, a novel synthetic strategy by an "electrostatic self-assembly and covalent fixation" technique has been proposed to construct a variety of topologically unique polymer architectures.

Journal Article↗

PubMed2004

Revised description and classification of atypical isolates of Pasteurella multocida from bovine lungs based on genotypic characterization to include variants previously classified as biovar 2 of Pasteurella canis and Pasteurella avium.

Strains deviating in key phenotypic characters, mainly isolated from cases of bovine pneumonia in five European countries, were genotyped in order to examine their genotypic relationship with Pasteurella multocida. Twenty-two strains of Pasteurella avium biovar 2, including variants in indole, xylose and mannitol, 18 strains of Pasteurella canis biovar 2 and variants of this taxon, five strains of P. multocida subsp. septica showing variations in indole and ornithine decarboxylase, nine strains of P. multocida subsp. multocida showing variation in ornithine decarboxylase and mannitol, and type strains of the subspecies of P. multocida were included. Ribotyping was used to examine the relationship of the strains, and 13 types, each containing between one and 20 isolates, were observed. Identical ribotypes were observed in some cases for P. avium biovar 2 and either P. canis biovar 2 or P. multocida subsp. septica. ITS (16S-23S rRNA internal transcribed spacer) fragment-length profiling showed identity of the majority of strains (47 of 52), representing all four taxa, with only five divergent strains. A 16S rRNA sequence comparison of 11 strains representing the main ribotype clusters showed 99.9 % similarity to the type strain of P. multocida subsp. multocida, but only 97.4 % similarity was obtained to P. canis (biovar 1) and 93.7 % to P. avium (biovar 1). A species-specific PCR test for P. multocida gave a positive result with biovar 2 variants of P. avium and P. canis. DNA-DNA hybridizations between strains of P. multocida, biovar 2 variants of P. avium and P. canis, and P. multocida subsp. septica confirmed similarity at the species level. It is proposed, on the basis of genotypic similarity, that P. multocida be reclassified to include the biovar 2 variants of P. avium and P. canis and that the existence of the biovar 2 variants of P. avium and P. canis is highly questionable. It is concluded that the redefined P. multocida is genotypically homogeneous, although phenotypically diverse lineages exist with respect to ornithine decarboxylase, indole and mannitol, characters that have been regarded as essential for identification to the species level. A formal reclassification of the species is not possible, however, since too few strains have been found to vary in these key characters. Considering the phenotypic diversity of P. multocida, identification will have to depend partly on genotypic methods and the source host also seems important for safe diagnosis.

Animals↗

PubMed2005

Congenital prepubic sinus: a variant of dorsal urethral duplication (Stephens type 3).

Abstract A 3-year-old boy was admitted for yellowish discharge from a tiny opening in the midline prepubic area on the dorsal base of the penis. No other symptom related to the genitourinary tract was noted. Sinuousgraphy showed a non-communicating sinus tract with the urinary tract. At surgical exploration, through a diamond-shaped incision, a 4.5 cm-long sinus was found that ended blindly as a fibrous cord at the anterior surface of the pubic symphisis. Histologically, it was lined by stratified squamous epithelium and surrounded by bundles of smooth muscle and collagen. According to Stephens' classification, the sinus appears to be a variant of dorsal urethral duplication of Stephens type 3.

Child, Preschool↗

PubMed1995

Misidentification syndromes in schizophrenia: case reviews with implications for classification and prevalence.

Misidentification syndromes represent false, delusionally-based identification of self and/or others. These are variants of the Capgras Syndrome. Although the frequency of misidentification syndromes in schizophrenic populations has not yet been established, the authors believe this syndrome is more prevalent than previously described. Seven of twenty-five (28%) consecutive patients admitted to a chronic clozapine unit with a variant of misidentification syndrome will be described. Their symptoms are categorised according to traditional classification, and Silva's proposed nomenclature. Problems inherent in these classifications are discussed. The need for a more systematic classification of misidentification syndromes is emphasised. Longitudinal studies of misidentification syndrome, and the development of a standardised assessment tool for clinicians who treat chronically psychotic patients, are encouraged.

Adult↗

PubMed2000

Artifacts, anatomical and physiological variants, and unrelated diseases that might cause false-positive whole-body 131-I scans in patients with thyroid cancer.

The whole body 131-I scan remains an important component in the postoperative treatment of patients with well-differentiated thyroid cancer. Because normal thyroid tissue remnants and residual or metastatic foci of well-differentiated thyroid cancer have the unique ability to concentrate, organify, and store 131-I, the whole body scan provides a depiction of those tissues that can be ablated with therapeutic doses of 131-I. Over time, it has become obvious that the whole body scan may also reveal foci of 131-i uptake owing to a wide variety of other causes. We provide a detailed pathophysiological classification of the artifacts, anatomic and physiological variants, and nonthyroidal diseases that may give rise to false-positive whole body scans in postoperative patients with thyroid cancer. These include ectopic foci of normal thyroid tissue; nonthyroidal physiological sites (eg, choroid plexus, salivary glands, gastric mucosa, urinary tract); contamination by physiological sections; ectopic gastric mucosa; other gastrointestinal abnormalities; urinary tract abnormalities; mammary abnormalities; serous cavities and cysts; inflammation and infection; nonthyroidal neoplasms; and currently unexplained causes. This article also provides a detailed review of the widely scattered English language literature in which these phenomena were originally described.

Artifacts↗

PubMed2003

The Madrid triple classification of dry eye.

From the clinical point of view, there are many etiologic causes, several combinations of anatomo-pathologic manifestations, and different grades of severity of Dry Eye diseases in the dysfunctional tear film syndrome. The dacryologist doctor must recognize these three parameters, quantify them, and establish the most appropriate treatment. The present triple classification has been elaborated for this purpose. First, there is an etiologic distribution in ten groups: age-related, hormonal, pharmacologic, immunopathic, hyponutritional, dysgenetic, inflammatory, traumatic, neurodeprivative, and tantalic. Each of these groups comprise many variants. Second, there is an anatomo-pathologic classification named ALMEN classification from the acronym of aquodeficiency, lipodeficiency, mucodeficiency, epitheliopathy, and non-ocular exocrine affectations. Finally, there is a severity classification in five grades: subclinical (symptoms only when overexposure), mild (habitual symptoms), moderate (symptoms plus reversible signs), severe (symptoms plus permanent signs), and disabling (all the above, plus visual discapacity).

Dry Eye Syndromes↗

PubMed2006

Cutaneous malignant lymphomas: update 2006.

Cutaneous lymphomas represent a unique group of lymphomas and are the second most frequent extranodal lymphomas. As with other neoplasias, the pathogenesis is based mainly on a stepwise accumulation of mutations of suppressor genes and oncogenes caused by genetic, environmental or infectious factors. The diagnostic work-up includes clinical, histological, imaging and hematological investigations and in many cases immunohistochemical and molecular biological analyses. The current WHO/EORTC classification of cutaneous lymphomas differentiates "mature T-cell and NK-cell lymphomas", "mature B-cell lymphomas" and "immature hematopoietic malignancies", their variants and subgroups. It is compatible with the WHO classification for neoplasias of the hematopoietic and lymphoid tissue and respects the organ-specific peculiarities of primary cutaneous lymphomas. The assignment of the various types of cutaneous lymphomas into prognostic categories (pre-lymphomatous "abortive" disorders; definite malignant lymphomas of low-grade malignancy; definite malignant lymphomas of high-grade malignancy) provides essential information on the biological behavior and allows an appropriate planning of the therapeutic strategy, which may be topical or systemic and aggressive or non-aggressive. Besides the classical options for therapy, there are new and "experimental" strategies, the efficacy of which has to be studied in clinical trials.

Dermatology↗

PubMed2000

2000 World Health Organization classification of tumors of the nervous system.

This is a review of the 2000 World Health Organization (WHO) classification of tumors of the nervous system. It contains an overview of the most important changes and short descriptions of the new entities or variants of already existing entities included in the current classification. These are: chordoid glioma of the third ventricle, cerebellar liponeurocytoma, large cell medulloblastoma, medulloblastoma with extensive nodularity and advanced neuronal differentiation, atypical teratoid/rhabdoid tumor, perineuroma, and rhabdoid meningioma. In contrast to the former WHO tumor classification series, the present one is based on the complex criteria, which include not only the clinical course and histologic appearance of the neoplasm but its immunophenotypic features and molecular/cytogenetic profile as well. Thus, it is strongly disease-oriented and uses extensively the recent advances in the basic sciences.

Humans↗

PubMed1997

[What is a virus?].

Viruses are simple biological particles, consisting of a genome, a protein capsid and, in the case of enveloped viruses, an external lipidic envelope. Owing to the presence of envelope, most enveloped viruses are fragile although some exceptions may be observed. Viruses behave as complete intracellular parasites. Their multiplication results from the replication and self-assembly of viral components, this process being directed by the viral genome after it has been released within an infected cell. Virus classification is now essentially based on molecular properties, concerning both the structure and replication strategy of viruses. In virus taxonomy, serial hierarchical levels are family, subfamily, genus and species. Within species, lower hierarchical levels are type, subtype, variant and strain. Knowledge of virus structure and classification is essential for considering the physiopathology, diagnosis and therapy of viral infections.

Humans↗

PubMed1998

Light scatter and immunophenotypic characteristics of blast cells in typical acute promyelocytic leukemia and its variant.

Acute promyelocytic leukemia (APL), defined by the French-American-British (FAB) classification as the M3 subtype of acute myeloblastic leukemia (AML), is readily diagnosed by direct cytomorphologic examination. The potential difficulty in recognizing the microgranular variant of APL (M3v) stems from the morphological characteristics of APL leukemic cells, which resemble monocytes. From 109 newly diagnosed acute leukemic patients, 48 were classified as AML and 16 of these patients (33%) had APL Mononuclear cells (MNC) of all APL patients were analyzed by flow cytometry for immunophenotypic features and forward and right angle scatter (FW-SC/RT-SC) light characteristics. Two clearly different FW-SC/RT-SC distribution patterns were recognized and defined as hypergranular (mature cells) and hypogranular (immature cells). Correlation between FW-SC/RT-SC patterns and the FAB system was poor: from eight patients classified as M3, six had the hypergranular pattern and two had the hypogranular pattern; from eight cases with M3, five and three patients had hypogranular and hypergranular patterns, respectively. The most relevant cellular immunophenotypic feature was the high frequency of CD34+ cases (5/7) recorded exclusively in patients with the hypogranular pattern. An interesting finding was that MNCs of all APL patients changed color from beige to green in the course of 3-4 h, whereas none of the 93 specimens of non-M3 acute leukemia cases showed this phenomenon. Summarizing, the FW-SC/RT-SC characteristics of APL blast cells along with the immunophenotype may represent an objective and reproducible measurement system to distinguish microgranular (M3v) from typical (M3) APL In addition, the present study has identified another unique feature of APL based on the green color of their blast cells imparted by the high content in myeloperoxidase.

Adolescent↗

PubMed1983

Adult non-Hodgkin's lymphoma. Correlation of cell surface marker phenotype with prognosis, the new working formulation, and the Rappaport and Lukes-Collins histomorphologic schemes.

The interrelationships between histomorphologic classification, cell surface marker phenotype and prognosis were prospectively studied in 130 adults with non-Hodgkin's lymphomas. Within each of the classification schemes used there were certain histologic variants that exhibited heterogeneity of cell lineage as well as those that were extremely uniform. Diffuse lymphomas with cell populations consisting of large cells, or mixtures of large and small cells were the most heterogeneous phenotypically and were most resistant to precise definition of immunologic cell lineage. The new Working Formulation for Clinical Usage likewise exhibited considerable heterogeneity of phenotype even within well defined histomorphologic categories. Two immunologic phenotypic variables that conferred a significant favorable prognosis were the expression of surface membrane immunoglobulin (B derivation) and the simultaneous expression of a membrane mu and delta immunoglobulin heavy chain. The results of this study suggest that cell surface marker phenotypic determinations have well defined and potentially useful correlations with histomorphologic classification schemes, and are useful in predicting biologic behavior and prognosis. It is suggested that a knowledge of both immunologic phenotype and histomorphologic characteristics is necessary in formulating therapeutic decisions.

Humans↗

PubMedDate not supplied

The diagnosis of borderline personality disorder: problematic but better than the alternatives.

BACKGROUND: The purpose of this review is to examine empirical evidence concerning critiques of the diagnosis of borderline personality disorder (BPD): for uncertain validity, and for overlap with other mental disorders. METHODS: A review of the literature on the validity and comorbidity of BPD was conducted. RESULTS: Since BPD is a complex multidimensional construct, its validity is inevitably problematic, but no more so than most other psychiatric diagnoses. The comorbidity of BPD is probably an artefact of the current classification system, and there is no convincing evidence that BPD is a variant of an Axis I disorder. CONCLUSIONS: Although further research should lead to changes in classification, the diagnosis of BPD retains significant clinical utility.

Borderline Personality Disorder↗

PubMedDate not supplied

[Angiographic study of the colonic vessels with a view to esophagoplasty].

Variants of the colic vessels were studied angiographically in 34 cadavers, drawing up an original classification of the colic arteries arising from the lower mesenteric artery. Sixteen variants of the left colic artery were found, which were grouped into five main types, the classical type being encountered in only 22.6% of the cases. In one case the lower mesenteric artery was absent. In coloesophagoplasty better results were obtained with the isoperistaltic transverse colon than with the upper ileocolon in 64% of the cases and similar results in 20%; in 16% of the cases the latter operation was preferable.

Angiography↗

PubMed1996

Myxoid liposarcoma with cartilaginous differentiation.

Common histologic variants of liposarcoma are readily recognized. Histologic classification might be difficult, however, when liposarcoma demonstrates cartilaginous differentiation. Although this phenomenon has previously been noted, it has not, to our knowledge, been reported as a specific pathologic entity. All three patients in the present study were men, ages 37, 42, and 63 years. Each presented with a solitary, enlarging mass of the thigh that was surgically excised. The tumors ranged in size from 8 to 13 cm. Microscopically, each lesion displayed characteristic features of myxoid liposarcoma; in addition, all possessed discrete, rounded foci of mature-appearing hyaline cartilage. One case displayed small foci showing chondrocyte atypia. No other patterns of mesenchymal differentiation were present. All patients received postoperative radiation therapy. No recurrences or metastases have been identified (mean duration, 39 mo). Myxoid liposarcomas with cartilaginous differentiation are of importance because they might be misdiagnosed as malignant mesenchymoma. The latter, if not qualified as to histologic grade, might be presumed to be a biologically more aggressive lesion. In addition, these lesions must be distinguished from two benign processes: chondroid lipoma and extraskeletal chondroma with lipoblast-like cells. Additional studies of this uncommon variant of liposarcoma will be necessary to document further its status as a low-grade sarcoma.

Adult↗

PubMed2026

Tackling non-canonical splicing in arrhythmogenic cardiomyopathy to reduce the uncertain significance variants burden.

BACKGROUND: Splice-altering variants (SAVs), particularly those outside canonical splice sites, are an underappreciated contributor to inherited cardiovascular diseases. In arrhythmogenic cardiomyopathy (ACM), these variants frequently remain classified as of uncertain significance (VUS) due to limited predictive power and lack of transcript-level evidence, constraining genetic yield and clinical management. Our study aimed to determine the functional impact of SAVs in ACM genes and refine their classification using ACMG/AMP and ClinGen SVI criteria. METHODS: SAVs identified in 200 ACM probands underwent SpliceAI prediction, GTEx cardiac exon-usage annotation, and functional assessment using pSPL3-based minigene assays. Aberrant transcripts were quantified using Percent Splicing Alteration (PSA). Segregation data and ACMG/AMP criteria refined by ClinGen SVI were applied to integrate functional and clinical evidence for classification. RESULTS: Aberrant splicing was confirmed in 9/20 variants (45%), including synonymous, missense, and non-canonical intronic changes. SpliceAI scores correlated strongly with PSA values (R²=0.86). Case-control burden testing revealed significant enrichment of splice-altering variants in DSP, DSG2, DSC2 and FLNC. Integrating predictive algorithms with experimental validation and segregation analysis markedly enhances reclassification of 16/20 variants (80%). CONCLUSION: Splicing defects beyond canonical sites significantly shape ACM genetic landscape. Integrating predictive models with experimental validation clarifies uncertain variants bridging the gap between genomic uncertainty and clinical decision-making.

Humans↗

PubMedDate not supplied

Ensemble methods for classification in cheminformatics.

We describe the application of ensemble methods to binary classification problems on two pharmaceutical compound data sets. Several variants of single and ensembles models of k-nearest neighbors classifiers, support vector machines (SVMs), and single ridge regression models are compared. All methods exhibit robust classification even when more features are given than observations. On two data sets dealing with specific properties of drug-like substances (cytochrome P450 inhibition and "Frequent Hitters", i.e., unspecific protein inhibition), we achieve classification rates above 90%. We are able to reduce the cross-validated misclassification rate for the Frequent Hitters problem by a factor of 2 compared to previous results obtained for the same data set with different modeling techniques.

Journal Article↗