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At least 127 records · Page 7Linked to original sources
PubMed1988

[Genetic variants of human albumin: structural characterization of allotypes used as references for electrophoretic classification].

Eight different types of genetic variants of albumin are observed in the French population. The analysis of electrophoretic patterns of sera containing these variants, performed a three different pHs (8.6, 5.0 and 6.9) after addition of a reference protein (transferrin), allows the identification each variant by a quantitative estimation of its relative mobilities. The accuracy and reproducibility of the technique make it a useful reference method, commonly employed for studying European variants. The samples used as references for five genetic variant types, proalbumins Christchurch and Lille, albumins Vanves, B and Reading, were subjected to sequence analysis to determine the nature and localization of their structural change. Together with the mutations of albumins Gent and Roma previously described, the data presented here make available seven reference specimens for which the structural changes are characterized out of the eight variants known to exist in France.

Amino Acid Sequence↗
PubMed1999

Boosted mixture of experts: an ensemble learning scheme.

We present a new supervised learning procedure for ensemble machines, in which outputs of predictors, trained on different distributions, are combined by a dynamic classifier combination model. This procedure may be viewed as either a version of mixture of experts (Jacobs, Jordan, Nowlan, & Hintnon, 1991), applied to classification, or a variant of the boosting algorithm (Schapire, 1990). As a variant of the mixture of experts, it can be made appropriate for general classification and regression problems by initializing the partition of the data set to different experts in a boostlike manner. If viewed as a variant of the boosting algorithm, its main gain is the use of a dynamic combination model for the outputs of the networks. Results are demonstrated on a synthetic example and a digit recognition task from the NIST database and compared with classifical ensemble approaches.

Algorithms↗
PubMed1989

[Clinico-morphologic parallels in malignant lymphoma].

Concurrent clinicomorphological studies were carried out in patients with malignant Hodgkin's and non-Hodgkin lymphomas treated in the Hematologic Clinic of the High Medical Institute in Pleven. The frequency of the different clinicomorphological variants and their classification in accordance with their initial localization, clinical stage and histological variant were studied. Some clinicomorphological features of the patients studied are analyzed.

Adult↗
PubMed1981

[Classification and the criteria of hypertrophy of the heart based on data from the weighing of its separate parts].

Variation statistical analysis of summary data of separate weighing parts of the hearts of 605 apparently normal subjects was carried out. The ranges of normal variations, the borders of the transitional zone, and criteria of pathology by 15 parameters of the myocardium weight were determined by the method of sigmal deviations and centil method. Two variants of pathoanatomical classification of changes in the heart weight are proposed. The first variant is based on two criteria: myocardial-height and ventricle indices. It includes 6 forms of changes of the muscle weight: absolute and relative hypertrophy of the right and left ventricles, combined hypertrophy of both ventricles, and myocardial atrophy. The second variant is based on comparative evaluation of the absolute weight of the right and left ventricles, allowing to distinguish 10 forms of changes of the myocardium weight. Both variants allow an objective and significant classification of any case. Nomograms have been compiled to facilitate the use of the classifications.

Adult↗
PubMed2001

A classification scheme for human polyomavirus JCV variants based on the nucleotide sequence of the noncoding regulatory region.

The human polyomavirus JCV is responsible for the central nervous system (CNS) demyelination observed in cases of progressive multifocal leukoencephalopathy (PML). Lytic infection of oligodendrocytes, the cells that constitute the basis of myelin in the CNS, is established by JCV in conjunction with immunosuppressive conditions. Beyond this, however, many questions related to JCV pathogenesis remain unanswered. The JCV regulatory region is a hypervariable noncoding sequence positioned between the early and late protein-coding regions. The particular nucleotide sequence of a JCV regulatory region affects levels of viral transcription and replication. Modifications to this promoter/enhancer structure can alter the cellular host range and may be responsible for switching JCV between states of lytic and latent infection. The regulatory region structure has, therefore, been used to distinguish JCV variants. Nucleotide sequencing studies have uncovered numerous variations of regulatory region structure. Until now, however, no inclusive nomenclature existed that linked variants by regulatory region structure and/or activity. We have arranged all known variant JCV regulatory regions into quadrants according to the integration of particular sequence sections and repetition of sequence section groups. This arrangement of regulatory regions results in an updated nomenclature that is well-suited for describing the relationships between JCV variants. Four distinct structural forms (I-S, I-R, II-S, and II-R) are defined along with tissue tropisms. This design provides logical connections between the variant regulatory regions and may be useful for elucidating crucial steps in JCV pathogenesis.

DNA, Viral↗
PubMed1990

[Classification of glucose-6-phosphate dehydrogenase enzymopathies: evaluation of kinetic parameters using multivariate methods].

The dependence between 9 kinetic parameters of glucose-6-phosphate dehydrogenase from 13 normal controls and 78 G6PD-deficient patients from the GDR and other socialist countries has been investigated by multivariate statistical methods. Using principal component analysis a two-dimensional presentation of the data was obtained from which similarities between individual enzyme variants became detectable. Conclusions could be drawn in how as far the kinetic parameters contribute to the discrimination between different variants. An objective classification of G6PD-variants was achieved by application of cluster analysis. The proposed methods provide an effective means for differential elucidation of G6PD-enzymopathies and should be also useful in the case of other enzymopathies.

Cluster Analysis↗
PubMed2000

Burkitt's lymphoma in Greek adults. A study of the Hellenic co-operative oncology group.

Non-African Burkitt's lymphoma is a rare disease among adults without AIDS. Among 1352 Greek adult patients with non-Hodgkin's lymphoma, 24 cases (1.8%) were classified as Burkitt's (BL) or Burkitt-like (BLL) lymphoma. Eleven cases fulfilled the criteria of BL and 13 of BLL. No statistical differences were found in the general characteristics of the two groups at the time of diagnosis. Extranodal involvement was a common finding in both groups and bulky disease (>10 cm) was observed in almost one half of the patients. The majority of the patients were treated with intensive, although different, protocols. After induction treatment, complete remission (CR) was achieved in 14 patients (60.8%). CR was reached in all cases with stage I-II, while in stage IV the CR rate was 30.4%. The median overall survival was 27 months. The median survival for BL was 13 months compared to 27 months in the BLL group (P=0.34). The data of the present retrospective analysis, indicated that there were not significant clinical differences between BL and BLL variants. Since BLL is still a non-reproducible category in the REAL classification, all BL variants must be treated uniformly with intensive protocols.

Adolescent↗
PubMed2026

Expansion of the allelic and phenotypic spectrum of MED25-related developmental disorder: novel compound heterozygous variants with structural domain implications.

MED25-related developmental disorder (Basel-Vanagaite-Smirin-Yosef syndrome) is a rare autosomal recessive disorder, defined by severe neurodevelopmental delay, corpus callosum abnormalities, ocular involvement, epilepsy, and marked facial appearance. MED25 pathogenic variants interfere with the functioning of the Mediator complex, which is responsible for RNA polymerase II transcription. We report a 9-year-old girl who presents with significant global developmental delay, agenesis of the corpus callosum, congenital cataracts, epilepsy, hypotonia, musculoskeletal abnormalities, and typical craniofacial features. Trio-based whole-exome sequencing revealed compound heterozygous variants in MED25: a maternally transmitted truncating variant (c.1366 C > T; p.Gln456*) and a paternally inherited missense variant (c.430 C > T; p.Leu144Phe). The new classification of the missense variant as potentially pathogenic is supported by a systematic ACMG re-evaluation supported by segregation analysis, phenotypic specificity, computational prediction, and structural localization in the MED25 Activator Interaction Domain (ACID). Comparative phenotypic analyses show strong agreement with reported cases but add more data to fine-tune clinical spectrum. This article broadens the allelic and phenotypic spectrum of MED25-related developmental disorder and highlights the need for comprehensive evaluation across molecular, structural, and phenotypic pathways to elucidate variant signature in rare genetic disease models correctly.

Humans↗
PubMed1986

Proposal for the nomenclature of human plasminogen (PLG) polymorphism.

Since its discovery, human plasminogen (PLG) polymorphism has received widespread acceptance in population genetics and forensic haematology. Due to the large number of variant alleles described, a PLG reference typing and Plasminogen Symposium was held, at which a nomenclature proposal was inaugurated. The technology of comparing PLG variants was based on isoelectric focusing and subsequent detection by caseinolytic overlay and 'Western' blotting. Typing results permitted comparison of so far described variant designations and resulted in a new nomenclature proposal for PLG polymorphism. It is recommended that the two most common alleles found in all investigated races be called: PLG*A (previously also PLG*1) and PLG*B (previously also PLG*2), the known variants with acidic pI: PLG*A1 to *A3, intermediate variants: PLG*M1 to *M5, PLG*M5 being functionally inactive, and basic variants: PLG*B1 to *B3. For future classification of newly discovered variants, samples should be compared at any of the laboratories participating in the reference typing.

Collodion↗
PubMed1979

Syndrome delineation. 2. Inborn errors of metabolism, deformities, and variant familial developmental patterns.

Classification of genetic disorders and birth defects into the following five categories aids in efficient patient evaluation, prognostic counseling, and therapy: malformations, dysplasias, inborn errors of metabolism, deformities, and variant familial developmental patterns. These categories highlight different pathogenetic aspects of disease processes. Mixed disorders with manifestations from the different categories may be of special significance.

Abnormalities, Multiple↗
PubMed1976

Human alcohol dehydrogenase ADH1, ADH2 and ADH3 loci in a mixed population of Bahia, Brazil.

1. The three structural gene loci of human alcohol dehydrogenase have been studied in liver, jejunum and lung from 300 newborns in a triracially mixed population of Bahia, Brazil. 2. The frequency of the ADH23 allele was 0-1392, suggesting that the ADH23 allele is less frequent in Negroes. 3. A new ADH2 variant was identified. The electrophoretic pattern was interpreted as due to a new allele which is provisionally called ADH2Bahia. 4. By electrophoretic classification the 'atypical' variant was found in 2-8% of the sample. A question is raised regarding the ancestral origin of the 'atypical' variant in the population. Because this variant is common in Japanese it may have reached the present day population of Bahia through their American Indian ancestors. 5. Subjective estimation of the proportions of beta chains by giving scores to the liver isozymes alphaalpha, alphabeta and betabeta showed a clear relationship between the fetal weight and the beta chain activity. 6. The proportion of beta chains in the liver is significantly less when there is no enzyme activity in the lung, indicating some synchronous 'turning on' mechanism for alcohol dehydrogenase synthesis in both tissues.

Alcohol Oxidoreductases↗
PubMed1985

Improved resolution of PI (alpha 1-antitrypsin) phenotypes by a large-scale immobilized pH gradient.

PI variants and PI M subtypes were examined by isoelectric focusing in a preformed immobilized pH gradient. Conditions were found that permit reliable classification of PI variants and of most PI M subtypes: the pH gradient ranges from 4.3 to 4.8 on a polyacrylamide gel with a length of 20 cm and a separation distance of approximately 16-17 cm (delta pH = 0.025 U/cm). The PI phenotypes observed are presented.

Humans↗
PubMed1977

Sucrose-negative variants of Candida tropicalis.

Four cultures of a Candida sp. that lacked alpha-glucosidase activity were isolated from clinical specimens. Physiological, morphological, and serological characterizations of the yeasts and deoxyribonucleic acid reassociation studies supported their classification as a variant of C. tropicalis.

Antigens, Fungal↗