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PubMedDate not supplied

[The classification of nervous system tumors].

The paper presents the classification of tumors of the nervous system, which is based on the Second Variant of the International Histological Classification of Tumors of the Nervous System which was developed by the WHO experts in 1993 and on the section "Morphology of Neoplasms" of the International Classification of Diseases, Xth review. These classifications were critically reviewed by taking into account the experience gained by the Laboratory of Pathomorphology, Academician N. N. Burdenko Research Institute, Russian Academy of Medical Sciences. The proposed classification may unify the material of our country's neurosurgical clinics and provide more corrective statistic data.

Humans↗

PubMed1995

Phylogenetic position of Rickettsia tsutsugamushi and the relationship among its antigenic variants by analyses of 16S rRNA gene sequences.

The 16S rRNA gene sequences of Rickettsia tsutsugamushi and Rickettsia sibirica were determined by PCR and DNA sequencing. Phylogenetic analysis revealed that R. sibirica is positioned in a cluster of the genus Rickettsia with a similarity value of 98.1-99.6%, whereas R. tsutsugamushi is located apart from the cluster with a similarity value of 90.2-90.6%. This evidence suggests that R. tsutsugamushi should be excluded taxonomically from the genus Rickettsia. The phylogenetic classification of six antigenic variants in R. tsutsugamushi moderately reflected their antigenic relationship known in closely and distantly related strains.

Antigens, Bacterial↗

PubMedDate not supplied

Automated white blood cell classification revisited.

A novel approach to the problem of automated white blood cell classification is described. Whereas in most earlier attempts the segmentation of the cells has been recognized as the most difficult and most critical step in the sequence of operations resulting in the classification, the method described here eliminates the necessity of the detection of the contour of the nucleus and of the cytoplasm, and is therefore less sensitive to such disturbing factors as the presence of granules, of other cells touching the cell of interest, etc. The multiple sequential threshold method to be described here in two slightly different variants yields a correct classification rate of 94.7% for a 4 class problem (90 cells in the test set), and 91.8% for an 8 class problem (279 cells in the test set). Both experiments include immature cell types.

Densitometry↗

PubMed1985

[Comparative analysis of the histological variants of renal cell cancer].

85 cases of renal-cell carcinoma are studied histologically, cytologically and electron-microscopically. Morphological variant was determined according to the classification of N. A. Krayevsky et al. Histological and cytological variants of renal-cell carcinoma, differences of the degree of their differentiation are shown. Electron-microscopically the cell types characteristic of clear-cell and granular-cell variants of a different degree of differentiation are distinguished. Similarity of cell ultrastructure in granular-cell, sarcoma-like and glandular tumour variants is found. The ultrastructural features of nephrocytes and renal tubules in the form of the accumulation of microvilli, cytoplasmic membrane invaginations, desmosomes, basal membrane fragments which are seen as the markers of the tumour organospecificity were preserved in all variants of renal-cell carcinoma studied.

Adult↗

PubMed2001

Rapid molecular analysis of the haemagglutinin gene of human influenza A H3N2 viruses isolated in spain from 1996 to 2000.

A simple molecular technique was used for the rapid preliminary genetic characterization of human influenza A H3N2 viruses isolated in Spain from 1996 to 2000. Subtyping, based on RT-PCR, was followed by subtype-specific restriction enzyme fragment length polymorphism (RFLP) analyses of an amplified region of the HA1 domain of the H3 haemagglutinin (HA) gene to distinguish variants differentiated by common amino acid substitutions in HA1. The approach was tested using 135 Spanish H3N2 isolates and included nucleotide sequencing and phylogenetic analyses of a region of the HA1 domain of 41 representative isolates. The viruses were distinguished by haemagglutination inhibition (HI) assays into two antigenically discernible groups, the A/Wuhan/359/95-like and A/Sydney/5/97-like viruses. The results of PCR-RFLP analysis allowed a finer classification into five genetic variant subgroups, corresponding to those distinguished by phylogenetic analyses. This rapid, simple and variant-specific procedure could, therefore, be used to rapidly screen clinical specimens prior to more detailed antigenic and genetic analyses.

Hemagglutinin Glycoproteins, Influenza Virus↗

PubMed2000

[Hepatic arterial vascular anatomy and its variants].

PURPOSE: We investigated the frequency of anatomical variants of the hepatic artery, which can influence interventional angiographic procedures. MATERIAL AND METHODS: We reviewed 150 consecutive angiograms performed for the treatment of primary (112) or metastatic (38) liver tumors and evaluated the frequency of anatomical variants of the hepatic artery based on the classification proposed by Michels in 1955, which describes 10 variants. The so-called typical anatomy, which is in fact only found in 55% of cases, is indicated as type I. RESULTS: The typical anatomy (type I variant) was seen in 78 patients (52%) and variants were seen in the other 72 (48%). We found 15 type II variants (10%), 23 type III (15.5%), 1 type IV and 1 type V (0.6%), 3 type VI (2%), 1 type VII (0.6%) and finally 6 type IX (4%). There were no type VIII or X variants, but in 22 patients (14.7%) vascular anatomy did not fit Michaels' classification. DISCUSSION AND CONCLUSIONS: In our series the typical hepatic artery anatomy was found in 52%, which is in agreement with Michels' findings, while the frequency of the individual anatomical variants differed. Not all of the variants reported by Michels were seen in our series and we found 22 patients with different variants. Disagreement might be due to the fact that Michels' was an autoptic series while our patients were cancer patients only and thus variability could be at least partly accounted for by neoplastic neovascularization. We believe that thourough knowledge of the anatomical variants of the hepatic artery is fundamental to angiographic practice, in particular for interventional procedures, because such variants can influence the choice of vascular technique and of materials.

Angiography↗

PubMedDate not supplied

[Variants of hermaphroditism (clinical findings)].

False and true hermaphroditism (FH and TH) are often encountered in surgery for hypospadia. A clinically validated classification of various types and variants of hermaphroditism is proposed. FH is divided into male FH and female FH. TH also falls into two categories: TH without anomalies of external genitalia and that with these anomalies. The latter category has three variants: 1) all genitalia of males or females and some genitalia of the other sex; 2) some female and male organs in various combinations; 3) all organs of both sexes. All TH variants are illustrated by 5 case reports. These patients were thoroughly examined and their sex was surgically corrected.

Adolescent↗

PubMed2026

Genetic diversity and molecular mechanisms in hypertrophic cardiomyopathy: toward personalized therapy.

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac muscle disorder, yet contemporary genomic and mechanistic research still lacks a cohesive model explaining how diverse genetic architectures give rise to heterogeneous phenotypes. This review synthesizes advances across sarcomeric and nonsarcomeric mutations, including intermediate-effect variants, polygenic modifiers, and ancestry-dependent sources of variant misclassification to elucidate how these factors govern disease penetrance and clinical expression. It critically evaluates how genetic diversity intersects with key molecular pathways, including sarcomeric hypercontractility, calcium dysregulation, mitochondrial energy deficiency, and transforming growth factor-β (TGF-β) and protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling, to drive hypertrophic and fibrotic remodeling. Emerging mechanism-based therapies, such as myosin inhibition, allele-specific silencing, clustered regularly interspaced short palindromic repeats (CRISPR)-based correction, and metabolic modulation, are examined with respect to their capacity to modify upstream molecular drivers rather than downstream hemodynamic consequences. Persistent challenges, including variants of uncertain significance classification, ancestry-biased databases, inequitable access to genetic testing, and unresolved safety concerns for gene-based therapies, are critically assessed as major barriers to precision-medicine integration. By linking genetic architecture, molecular pathogenesis, and targeted interventions, this review advances a contemporary, mechanistically grounded framework that informs both individualized management and future research directions. Future research should prioritize pathway-specific therapeutics, functional and mechanistic validation of emerging variants, deeper physiologic phenotyping to refine disease modeling, and accelerate translation throughout the continuum of HCM pathophysiology.

Humans↗

PubMed2004

A harmonic structure of the genetic code.

In this paper is presented a new, very harmonic structure of the genetic code (GC) within a system of "4 x 5" (and/or of "5 x 4") of amino acids (AAs) in two variants. In first variant, the five rows within the system start with one polar charged amino acid (AA) each, making first column, consisting from five polar charged AAs (D, R, K, H, E). Five polar non-charged AAs (N, P, Y, W, Q) follow, then five non-polar AAs as last column (A, L, F, V, I) and, finally, five polar or non-polar AAs, in a combination, as first to last column (A as non-polar; S, T as polar, and G, P as ambivalent AAs). A second variant is subsequent to this one-"4 x 5" system with five nitrogen AAs (K, R, P, H, W), five oxygen (D, E, Y, S, T), five solely carbon (A, L, F, V, I) and five "combined" AAs (G with hydrogen as side chain; C and M with carbon and sulfur; N and Q with carbon, oxygen and nitrogen). A strict balance of atom and nucleon number as well as molecule mass follows the classification in both system variants.

Amino Acids↗

PubMed1994

[The current diagnosis of acute nonlymphoblastic leukemias].

The paper presents the results of the retrospective study of blast cells from 377 patients with acute nonlymphoblastic leukemia (ANLL). Morphocytochemical, immunological, cytogenetic assessments and cloning in semisolid agar were employed. The authors specify blast characteristics with reference to ANLL variants according to the FAB classification, define diagnostic criteria for poorly differentiated myeloblastic (MO), erythroblastic (M6) and megakaryoblastic (M7) leukemia, hybrid variants.

Adult↗

PubMed2007

[Mediastinal large B-cell lymphoma].

Mediastinal B-cell lymphoma is a locally highly aggressive tumour which was first described in the early 1980s. The incidence is about 2-3% of all non-Hodgkin's lymphomas. The conceptional evolution of this lymphoma entity was hampered by its low incidence and the broad spectrum of morphological variants present. However, since mediastinal B-cell lymphoma has distinct morphological, immunological, genetic, and clinical features, it has been listed in the revised European-American Classification of Lymphoid Neoplasms (REAL-Classification) since 1994 as a variant of diffuse large B-cell lymphoma. In the World Health Organization classification of malignant lymphomas, mediastinal B-cell lymphoma is now listed with an own disease code (ICD-9679/3).

Humans↗

PubMed1983

Creatine kinase variants. Report on the workshop conference of the German Society for Clinical Chemistry held on September 19 to 21, 1982 in Tübingen, FRG.

It was the aim of the workshop to summarize present knowledge of the variant creatine kinases in human blood. Discussion was centered on the nature, measurement, and clinical significance of these variants. On the basis of the presented results, the different creatine kinase variants can be classified as follows: Normal size variants (80000 Daltons). These originate from postsynthetic modifications of the three dimeric isoenzymes creatine kinase-MM, MB or BB. The M subunit can be transformed by a serum constituent and these modifications result in at least three different creatine kinase-MM and two creatine kinase-MB variants, which still show catalytic activity. The mechanism of the postsynthetic alterations of creatine kinase-BB seems to be more complex: In vitro incubation of this isoenzyme even in a non-serum matrix changes its electrophoretic mobility and decreases activity. In vivo there is evidence that on the one hand intact creatine kinase-BB molecules are directly removed from the circulation. On the other hand, however, inactive creatine kinase-BB-protein is reported to occur in serum. Variants with higher molecular weights (greater than 200000 Daltons). These are termed macro creatine kinases. Macro creatine kinase type 1 comprises the immunoglobulin-bound creatine kinase isoenzymes. Of these immune complexes, IgG-linked creatine kinase-BB is well known and has been described in detail, whereas the occurrence of creatine kinase-MM-containing macro creatine kinases is still questionable. Macro creatine kinase type 1 is found in the blood of about 2% of all hospitalized patients. It occurs mainly in elderly women, but it is not known whether it has any special clinical significance. Macro creatine kinase type 2 is the term for an oligomeric form of mitochondrial creatine kinase released after breakdown of mitochondria in liver, heart and some tumours. After treatment with urea this oligomeric form is converted into a normal sized, dimeric creatine kinase-MiMi. Macro creatine kinase type 2 is found exclusively in seriously ill patients, and may occur in more than 3% of all hospitalized patients. This classification of the creatine kinase variants seems logical, since it takes into account the nature of the creatine kinase variants, and it permits the classification of all atypical creatine kinases described in the literature. As quantification and differentiation now become possible, further experimental and clinical investigations should provide the information necessary for a better understanding of the physiology and pathobiochemistry of these multiple forms of creatine kinase.

Creatine Kinase↗

PubMed1988

Malignant fibrous histiocytoma: the most common soft-tissue sarcoma.

Although soft-tissue sarcomas account for less than 1% of all malignancies, over 55 different histological variants have been described. Consequently clinicians often find the classification both complex and confusing. A new variant, the malignant fibrous histiocytoma (MFH), is now the most common adult soft-tissue sarcoma, therefore a clear understanding of the diagnosis, its implications and the optimum treatment is desirable.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

[A case of GM-Gangliosidosis (atypical form of the AB variant)].

A case of GM-gangliosidosis, variant AB, with some atypical feautres is reported in a male child, who died at the age of 4 years and 3 months. When he was 2 and a half years old, he showed signs of progressive cerebral disease with increasing motor and mental impairment. The clinical signs suggested a form of neurolipidosis; however the data of the enzymatic activities of the peripheral blood leucocytes did not show any deficit related to these forms. More specifically the values of the exosaminides A and B were normal, although the component A was near the lowest limit of the range. The anatomical, histological, histochemical, ultrastructural and chemical studies showed that it was a form of GM-gangliosidosis with visceral involvement. In the crude lipid extracts of various organs there was not only GM-ganglioside, but also a compound not previously demonstrated in these forms of neurolipidosis. Chemically this compound may be considered a phosphoglyco-lipid-and protein complex. From the enzymatic data in the peripheral blood leucocytes, the case may be a variant AB of the Sandhoff and al. classification (1971). However some clinical signs make our case closer to the 3th type of the O'Brien and al, classification while some histopathological aspects are similar to Tay-Sachs disease (i.e. to the variant B of the Sandhoff et al. classification; i.e. to the 1th type of the O'Brien et al. classification). These data, and the presence of an 'unknown compound', not yet demonstrated in the known forms of GM-gangliosidosis, support the hypothesis that our case may be considered as an 'atypical' form of the variant AB of the gangliosidosis GM and that further studies are necessary to reach a final nosography of these entities.

Brain Chemistry↗

PubMed1996

[Rare variants of cutaneous T-cell lymphomas].

Besides the classical forms of cutaneous T-cell lymphoma (C-CTCL), such as mycosis fungoides and Sézary's syndrome, unique variants may be encountered. The classification of these rare cutaneous T cell lymphomas is problematic and controversial. Newer classifications of lymphoma in general, such as the Revised European-American Lymphoma (REAL) Classification, emphasize well-established clinico-pathological entities. It seems appropriate to attempt to bring greater clarity to the classification of cutaneous T-cell lymphomas using the same principles. In this review, we list and characterize the rare variants of cutaneous T-cell lymphoma, such as (1) clinical, histological and immunological variants of mycosis fungoides; (2) progressive cutaneous T-cell lymphoma (P-CTCL) including transformed classical cutaneous T-cell lymphoma (TC-CTCL) and primary progressive cutaneous T-cell lymphoma (PP-CTCL); (3) angiocentric and angioimmunoblastic cutaneous T-cell lymphomas; (4) large cell anaplastic, CD30+ cutaneous T-cell lymphoma; (5) HTLV-I-associated adult T-cell leukemia/lymphoma (ATLL); (6) cutaneous manifestations of primary extracutaneous T-cell neoplasias; (7) unclassifiable cutaneous T-cell lymphoma.

Antigens, CD↗

PubMed2006

Primary focal segmental glomerular sclerosis in children: clinical course and prognosis.

To review the clinical course and identify prognostic factors, we retrospectively analyzed 92 children with steroid-resistant primary focal segmental glomerulosclerosis (FSGS). The mean age of onset was 80.4+/-42.4 months. The mean follow-up duration was 98.2+/-63.3 months. Eighty-five patients presented with nephrotic syndrome and seven presented with asymptomatic proteinuria. Thirty-three patients were initial responders to steroid treatment (late non-responders) and 59 were initial nonresponders. At last follow-up, 36 patients (39.1%) were in complete remission, and 29 (31.5%) progressed to chronic renal failure (CRF). Renal survival rates at 5, 10, and 15 years were 84, 64, and 53%, respectively. By morphological classification, there were tip variants (6.1%), collapsing variants (10.6%), cellular variants (1.5%), perihilar variants (9.1%), and NOS (not otherwise specified, 72.7%). Among the variants, there were no significant differences in age of onset, degree of proteinuria, response to treatment, or progression to CRF. Poor prognostic factors for CRF included: asymptomatic proteinuria at presentation, initial renal insufficiency, higher segmental sclerosis (%), severe tubulointerstitial change, initial nonresponse, and absence of remission. In the multivariate analysis, an increase in the initial serum creatinine and resistance to treatment were independent risk factors for CRF. A more prolonged use of corticosteroid therapy and early introduction of cyclosporin A (CsA) may improve the prognosis for primary FSGS in patients with initial steroid nonresponsiveness.

Adolescent↗

PubMed2006

An analysis of unclassified missense substitutions in human BRCA1.

Classification of rare sequence variants observed during mutation screening of susceptibility genes in high-risk individuals presents an interesting and medically important challenge. A recently described method for analysis of unclassified variants in BRCA1 and BRCA2 provides an extensible framework within which several different types of analytic data can be integrated. Among the methods already integrated in this framework are a measure of sequence conservation at specific positions in BRCA1 and BRCA2, and a measure of the difference between wild-type and missense amino acid residues, the Grantham Matrix Score. Recently, we extended the idea of Grantham Matrix Scores to multiple sequence alignments by introducing two new measures, the Grantham variation and Grantham Deviation. We also created a measure of risk associated with sets of BRCA1 missense substitutions, the BRCA1-with-BRCA2 Ascertainment Ratio. Here, we complement these measures with a more powerful measure of risk associated with sets of missense substitutions, the Missense Enrichment Ratio. By combining these four measures, we demonstrate two points: (1) pooled evidence is completely in accord with a hypothesis that missense substitutions that fall at variable positions in the alignment of vertebrate BRCA1s and are within the range of variation observed at those positions are neutral, and (2) many of the missense substitutions falling at invariant positions in the alignment must be deleterious and the longer the period over which the position has been invariant, the stronger the evidence that this is so.

Amino Acid Sequence↗

PubMed2001

Low-grade gliomas.

Low-grade gliomas are uncommon primary brain tumors classified as histologic grades I or II in the World Health Organization (WHO) classification. The most common variants are pilocytic and low-grade astrocytomas, oligodendrogliomas, and mixed oligo-astrocytomas located in the cerebral hemispheres. Prognostic factors that predict progression-free and overall survival include young age, pilocytic histology, good Karnofsky performance status, gross total resection, lack of enhancement on imaging, and small preoperative tumor volumes. Edema and vasogenic effects are typically managed with corticosteroids. Dexamethasone is given at an initial dosage of 4 mg given four times daily. Anticonvulsants are given prophylactically after resection and for patients who present with seizures. The rationale for open craniotomy depends on the need for immediate palliation of symptoms by reduction of intracranial pressure or focal mass effect, and/or improved oncologic control. Gross total resection of tumor is generally defined as the absence of residual enhancement on contrast-enhanced postoperative MRI scan. Most retrospective studies suggest that patients who have undergone a gross total resection of tumor have improved survival. Depending upon the proximity of the tumor to eloquent brain, gross total resection may or may not be possible. In these cases a stereotactic biopsy is required to provide the histologic diagnosis. Adjuvant radiotherapy is recommended for patients with incompletely resected grade II tumors or for patients older than age 40 regardless of extent of resection. It may be considered for any pilocytic astrocytoma from which a biopsy has been performed. Phase III randomized prospective trials have shown statistically significantly improved progression-free survival at 5 years with the addition of radiotherapy, though overall survival does not appear different. Based on prospective randomized phase III trials, 50.4 Gy to 54 Gy of conventionally fractionated radiotherapy appears to be a safe and effective regimen with minimal neurotoxicity; 45 Gy may be adequate for biopsied pilocytic astrocytomas. Currently, RTOG trial 98-02 is investigating the efficacy of postradiation PCV chemotherapy (procarbazine, CCNU, and vincristine) in the treatment of newly diagnosed unfavorable low-grade gliomas. Other areas of investigation include Temozolomide chemotherapy and the association of 1p and 19q chromosomal deletions with prolonged survival in oligodendrogliomas and sensitivity to PCV chemotherapy. Radiosurgery and/or experimental chemotherapy may provide some measure of local control in the recurrent disease setting.

Adolescent↗