Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Recurrent variant”

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 181 records · Page 10Linked to original sources
PubMed1991

Estimating allele frequencies of hypervariable DNA systems.

Several polymorphisms of human DNA have been shown to be hypervariable due to the recurrence of a variable number of tandem repeats (VNTRs) in the lengths of allelic restriction fragments. The recurrence of allelic variants in this novel class of polymorphisms seems to comply well with a model of continuous random variables. Based on this assumption, we have compiled some simple algorithms for classification of continuous data and estimation of classes of relative frequencies and have implemented these routines for the management of databases storing hypervariable single locus DNA genetic systems. The algorithms are compiled in BASIC language and can be incorporated in task-oriented computer programs. Three procedures are discussed, based in turn on: (a) using predetermined, arbitrary classes; (b) point estimations of frequencies for single fragments using error measurements associated with the kilobase value assignment; (c) estimates of phenotype frequencies according to error measurements. Error measurements are obtained from a statistic of values pertaining to several restriction fragments (genomic controls) repeatedly tested in different experiments. Problems related to these approaches are discussed.

Algorithms↗
PubMed2005

Primary chronic sclerosing osteomyelitis--a case-report.

A case of primary chronic sclerosing osteomyelitis of the fibula in a 14-year-old is described. This rare condition can be difficult to differentiate from a bone tumor. Its pathogenesis is controversial, although the prevalent hypothesis involves chronic osteomyelitis developing after an unrecognized phase of acute infection. The existence of primary chronic sclerosing osteomyelitis as a disease in its own right has been challenged. Recently, primary chronic sclerosing osteomyelitis has been interpreted as a localized or monofocal variant of multifocal recurrent chronic osteitis or of the bone abnormalities associated with seronegative spondyloarthropathies (SAPHO syndrome).

Adolescent↗
PubMed2006

Associative sequence learning in humans.

In a series of experiments using the serial reaction time paradigm, the authors compared the predictions of a powerful associative model of sequence learning (the simple recurrent network; J. L. Elman, 1990) with human performance on the problem devised by A. Maskara and W. Noetzel (1993). Even though the predictions made by the simple recurrent network for variants of this problem are often counterintuitive, they matched human performance closely, suggesting that performance was associatively based rather than rule based. Simple associative chaining models of sequence learning, however, have difficulty in accommodating these results. The authors' conclusion is that, under the conditions of the experiments, human sequence learning is associatively driven, as long as this is understood to mean that a sufficiently powerful means of extracting the statistical regularities in the sequences is in play.

Adolescent↗
PubMed1998

Delusions and hallucinations in patients with borderline personality disorder.

To clarify the nature of delusional and hallucinatory symptoms in borderline personality disorder (BPD), the authors investigated five patients with BPD who developed those symptoms, and discussed their duration, recurrence, types of variants and relation to the situation. The duration of these symptoms tended to vary widely, although six of 11 episodes lasted more than 7 days. Episodes tended to recur in all patients two or three times. Each episode could be classified into three types of delusions and hallucinations, such as delusions without hallucinations, complicated delusion and hallucination, and hallucinations without delusion. Delusions without hallucination occurred a total of four times in two patients and had a tendency to occur when the patient confronted personal adversities. They projected their feelings directly toward the person concerned. A complicated delusion and hallucination was observed three times in two patients. This type of symptom also tended to occur at the time of interpersonal problems but the patient's attitude was more passive. Hallucination without delusion occurred a total of four times in three patients. This symptom tended to occur when the patient avoided an interpersonal relationship. In this case the patients isolated themselves from others and withdrew.

Adolescent↗
PubMed1986

The value of radiation therapy as an adjuvant to surgery in intracranial meningiomas.

Our experience with benign and malignant intracranial meningiomas between 1970 and 1983 is reported. Fourteen cases were treated after surgery, 10 benign and four malignant, following complete or incomplete resection or recurrence after resection. Two of 10 benign meningiomas have recurred and one of the two has been controlled by reoperation. None of the malignant meningiomas have been cured, but disease-free intervals up to 4 years were noted. The mean radiation dose was 5,400 rad, given with complex fields and shrinking field technique with no major complications. Adjuvant radiation after resection of meningiomas results in frequent cure of benign meningioma and may extend the interval of recurrence in malignant variants.

Adult↗
PubMed2026

Microglial GRB2 is essential for brain ventriculogenesis and CSF homeostasis.

Microglia play essential yet poorly understood roles in brain development, including axon guidance, regulation of neurogenesis, and pruning of neuronal projections. Congenital hydrocephalus (CH), characterized by enlarged cerebrospinal fluid (CSF)-filled ventricles, is a leading cause of pediatric brain surgery, but its molecular mechanisms remain unclear. We have identified what we believe to be novel, recurrent, damaging missense variants in the SH3-binding domain of the adaptor protein Growth Factor Receptor-Bound Protein 2 (GRB2) in unrelated patients with CH. GRB2 is significantly co-expressed with one of its known upstream receptor tyrosine kinase partners, CSF1R, in the developing human brain, particularly in a microglial subtype associated with regulation of neural stem cells. Immunoprecipitation validated GRB2-CSF1R binding in mouse microglial cells and human monocyte cell line. Cx3cr1-Grb2fl/fl mice engineered with conditional deletion of Grb2 in microglia exhibit congenital absence of microglia and early postnatal severe communicating (non-obstructive) hydrocephalus, mimicking GRB2-mutant patients. The severe ventriculomegaly of Cx3cr1-Grb2fl/fl mice is associated with both depletion of cerebral cortical neurons and impairment of glia-lymphatic-mediated CSF flow. Together, these findings implicate a role of GRB2 in microglia that could be essential for brain development and CSF homeostasis.

Genetics↗
PubMed1999

Genetic Aspects of Immunopathology in Prenatal and Postnatal Period.

The development of immunopathology in prenatal and postnatal periods has been studied with special refer to immune interaction character in mother-fetus system and inherited HLA DR genes. The immune variant of customary recurrent abortion has been shown to be associated with the HLA DR2 and HLA DR6 genes, with poor immune recognition of fetus HLA antigens and absence of serum suppressive factors in women. The distorted immune interactions with HLA antigens in the mother-fetus system are transformed into the neonatal period as purulent-septic diseases and hemolytic disease of the newborns. The development of immunopathology, the maturation of main immunity parameters and postvaccinal immune response in the first-year-infants are associated with the inherited HLA DR genes.

Journal Article↗
PubMed2003

Susceptibility of herpes simplex virus isolates to nucleoside analogues and the proportion of nucleoside-resistant variants after repeated topical application of penciclovir to recurrent herpes labialis.

Subjects received topical penciclovir for 4 days during successive episodes of recurrent herpes labialis. Isolation of herpes simplex virus (HSV) was attempted from lesions obtained before initiation of treatment and on each day of therapy. Isolates remained sensitive to penciclovir when tested by a plaque reduction assay, and there was no significant change in sensitivity during any treatment course or between successive treatments. The proportion of nucleoside-resistant variants present within a subset of these isolates was further investigated using a more-sensitive plating efficiency assay. Although the proportion of antiviral-resistant HSV variants increased on successive days, it invariably remained a minor subpopulation. Moreover, isolates from successive episodes obtained before treatment showed no change in the proportion of resistant HSV variants. We conclude that antiviral-resistant variants, which are readily detected in HSV isolates from peripheral lesions, do not accumulate in the sensory ganglia of immunocompetent patients receiving multiple courses of nucleoside analogues.

Acyclovir↗
PubMed2000

The linkage disequilibrium between chloroplast DNA and mitochondrial DNA haplotypes in Beta vulgaris ssp. maritima (L.): the usefulness of both genomes for population genetic studies.

The structure and evolution of the plant mitochondrial genome may allow recurrent appearance of the same mitochondrial variants in different populations. Whether the same mitochondrial variant is distributed by migration or appears recurrently by mutation (creating homoplasy) in different populations is an important question with regard to the use of these markers for population genetic analyses. The genetic association observed between chloroplasts and mitochondria (i.e. two maternally inherited cytoplasmic genomes) may indicate whether or not homoplasy occurs in the mitochondrial genome. Four-hundred and fourteen individuals sampled in wild populations of beets from France and Spain were screened for their mitochondrial and chloroplast polymorphisms. Mitochondrial DNA (mtDNA) polymorphism was investigated with restriction fragment length polymorphism (RFLP) and chloroplast DNA (cpDNA) polymorphism was investigated with polymerase chain reaction PCR-RFLP, using universal primers for the amplification. Twenty and 13 variants for mtDNA and cpDNA were observed, respectively. Most exhibited a widespread geographical distribution. As a very strong linkage disequilibrium was estimated between mtDNA and cpDNA haplotypes, a high rate of recurrent mutation was excluded for the mitochondrial genome of beets. Identical mitochondrial variants found in populations of different regions probably occurred as a result of migration. We concluded from this study that mtDNA is a tool as valuable as cpDNA when a maternal marker is needed for population genetics analyses in beet on a large regional scale.

Chenopodiaceae↗
PubMed1981

[Clinical trial of a variation of combined radiation therapy of recurrent rectal cancer in women].

The results of clinical testing of the variant of associated radiotherapy for recurrent rectal cancer in 34 female patients are reported. Distant grid gamma therapy in the regime of uneven irradiation was associated with intracavitary irradiation and gammatherapy from open fields. An average focal dose under uneven irradiation was 86 Gy (8600 rad) in intracavitary gammatherapy--30 Gy (3000 rad), in open field irradiation--30 Gy (3000 rad), the radiation stress being 1.5-2 times increased within the limits of normal tisues tolerance compared with routine variants of irradiation. No marked radiation injuries hampering the continuation of the treatment were observed in the period to follow. Among 34 patients in 8 (23.5%) the complete tumor regression was gained.

Adenocarcinoma↗
PubMed1994

An estrogen receptor genetic polymorphism and the risk of primary and secondary recurrent spontaneous abortion.

OBJECTIVE: A case-control study was undertaken to assess the association between an estrogen receptor gene variant and the risk of recurrent spontaneous abortions. STUDY DESIGN: The frequency of the estrogen receptor gene variant in blood lymphocyte deoxyribonucleic acid and other selected maternal characteristics was compared among 60 primary recurrent aborters, 61 secondary recurrent aborters, and 43 women who had had at least two live births but no spontaneous abortions. RESULTS: No association was evident between the estrogen receptor gene variant and the risk of either primary or secondary recurrent abortion. There were data suggesting that primary recurrent aborters in particular were more likely to report a family history of recurrent abortion and a family history of breast cancer. CONCLUSIONS: These findings indicate that the estrogen receptor polymorphism is not a genetic marker for recurrent spontaneous abortions. Therefore, as suggested by previous investigations, this polymorphism appears to be a marker for breast cancer risk only among the subgroups who have had a history of repeated abortions.

Abortion, Habitual↗
PubMed2026

A Novel De Novo STAG1 Variant at the RAD21 Binding Interface Is Associated With Hypoglycemia, Recurrent Fever, Immunodeficiency and Features of Classical Cohesinopathies.

The cohesin complex, composed of SMC1, SMC3, RAD21, and STAG1/STAG2, is essential for chromosome cohesion, DNA repair, and transcriptional regulation. Pathogenic variants in cohesin components cause cohesinopathies. The classical characteristics of cohesinopathies include developmental delay (DD), intellectual disability (ID), feeding difficulties, hypotonia, short stature, hearing loss, and dysmorphic features. Here, we present a 5-year-old boy with classical cohesinopathy features, including DD/ID and feeding difficulties, along with non-classical features such as hypoglycemia, recurrent fever, and immunodeficiency. Trio exome sequencing identified a novel de novo missense variant of uncertain significance (NM_005862.3:c.643G>A(p.Val215Ile)) in the STAG1 gene. The variant localizes to the RAD21 interaction interface, and molecular dynamics (MD) simulations revealed conformational changes comparable to other STAG1 variants reported as likely pathogenic in patients, supporting a deleterious effect which may disrupt the STAG1-RAD21 interaction interface. This case expands the phenotypic and molecular spectrum of STAG1-related cohesinopathy and advances our understanding of the disease mechanism.

STAG1↗
PubMed1986

Correlation between automated DNA ploidy measurements of Hürthle-cell tumors and their histopathologic and clinical features.

The treatment of Hürthle-cell tumors of the thyroid is controversial because of their rarity and the inconsistent histopathologic criteria for their diagnosis. In order to obtain more objective criteria for the management of Hürthle-cell tumors, the nuclear DNA content of cells from 20 cases was measured with the MicroTICAS system and the correlation between the DNA distribution patterns and the clinical and histopathologic findings was evaluated. Three main DNA patterns were found: euploid, polyploid and aneuploid. The euploid or polyploid Hürthle-cell tumors came from patients who did not develop distant metastases or recurrence whereas the aneuploid variants came from patients who died of their disease and/or developed distant metastases and recurrence. Various correlation analyses were performed between DNA ploidy and age, sex, size of tumor, growth pattern, pleomorphism, invasion and metastases. Our data suggests that an aneuploid DNA pattern or one with a large percentage of aneuploid nuclei with DNA content exceeding 5N may predict eventual metastases or recurrence from Hürthle-cell tumor.

Adenoma↗
PubMed2003

The recurrent IgH translocations are highly associated with nonhyperdiploid variant multiple myeloma.

Aneuploid is ubiquitous in multiple myeloma (MM), and 4 cytogenetic subcategories are recognized: hypodiploid (associated with a shorter survival), pseudodiploid, hyperdiploid, and near-tetraploid MM. The hypodiploid, pseudodiploid, and near-tetraploid karyotypes can be referred to as the nonhyperdiploid MM. Immunoglobulin heavy-chain (IgH) translocations are seen in 60% of patients. We studied the relation between aneuploidy and IgH translocations in MM. Eighty patients with MM and abnormal metaphases were studied by means of interphase fluorescent in situ hybridization (FISH) to detect IgH translocations. We also studied a second cohort of 199 patients (Eastern Cooperative Oncology Group [ECOG]) for IgH translocations, chromosome 13 monosomy/deletions (Delta13), and ploidy by DNA content. Mayo Clinic patients with abnormal karyotypes and FISH-detected IgH translocation were more likely to be nonhyperdiploid (89% versus 39%, P <.0001). Remarkably, 88% of tested patients with hypodiploidy (16 of 18) and 90% of tested patients with tetraploidy (9 of 10) had an IgH translocation. ECOG patients with IgH translocations were more likely to have nonhyperdiploid MM by DNA content (68% versus 21%, P <.001). This association was seen predominantly in patients with recurrent chromosome partners to the IgH translocation (11q13, 4p16, and 16q23). The classification of MM into hyperdiploidy and nonhyperdiploidy is dictated largely by the recurrent (primary) IgH translocations in the latter.

Aneuploidy↗
PubMed2004

Fine-needle aspiration of primary and recurrent benign fibrous histiocytoma: classic, aneurysmal, and myxoid variants.

There is a limited number of correlative cytopathological studies of fibrous histiocytoma (FHC). To better define cytopathological criteria of diagnosis, we have reviewed fine-needle aspirates (FNA) from 36 FHCs (32 classical, 1 myxoid, and 3 aneurysmal variants on corresponding histological sections). Original cytological diagnoses were benign in 33 (91.7%) cases (22 accurate) and false positive in 3 (8.3%) cases. All smears were surprisingly homogenous and composed of histiocytic cells with finely vacuolated cytoplasm in 27 (75%) cases, small regular spindle cells in 25 (69%) cases, and giant cells in 17 (47%) cases. Histiocytic cells were attached to vascular structures in 9 (25%) cases. Slight cytonuclear atypia was seen in five (14%) cases. Three (8.3%) cases showed numerous siderophages. In two (5.6%) cases, there were abundant inflammatory backgrounds and in one (3%) case there was a scant myxoid background. Storiform patterns, round cells, prominent atypia, necroses, or mitotic figures were not seen. FHC should be differentiated from other benign, low- and intermediate-grade spindle-cell neoplasms such as low-grade fibrosarcoma, dermatofibrosarcoma protuberans, nodular fasciitis, spindle-cell malignant melanoma, and monophasic synovial sarcoma. Some cases may be misinterpreted as malignant, especially in cases of recurrence or in patients with a cancer history.

Adolescent↗
PubMed1999

The Tall cell variant of papillary carcinoma of the thyroid: cytologic features and loss of heterozygosity of metastatic and/or recurrent neoplasms and primary neoplasms.

BACKGROUND: The Tall cell variant of papillary carcinoma of the thyroid (TCV) is characterized by the proliferation of oxyphilic, tall, columnar cells with a height-to-width ratio of at least 2:1. TCV exhibits more aggressive clinical behavior than conventional thyroid papillary carcinoma (CPC). Cytologic features suggestive of TCV have been described in fine-needle aspiration material from primary tumors. Similarly, loss of heterozygosity (LOH) for chromosome 1 (D1S243) and the p53 gene (TP53) have been reported in TCV but not in CPC, thus making exploitation of this genetic feature a potential tool for molecular discrimination between these two neoplasms. METHODS: Cytology samples of metastatic and/or recurrent neoplasms (M/R) (12 cases) and 7 cases of primary TCV obtained from 12 patients were evaluated. The cytologic findings of these cases were compared with previously published findings. Microdissection and polymerase chain reaction for LOH for chromosome 1 and p53 (D1S243 and TP53 markers) were performed on cytologic smears from 6 cases of M/R tumors and 3 cases of primary tumors. RESULTS: More then 50% of M/R showed atypical follicular cells with enlarged nuclei, granular chromatin, nuclear grooves, pseudoinclusions, and abundant finely granular cytoplasm. Cells were disposed in monolayers (58%) and papillary clusters (50%). Similar findings were present in cases of primary TCV. LOH studies showed that 4 of 6 M/R were noninformative and 2 of 3 cases of primary TCV were informative for the D1S243 marker; however, in contrast with previously published reports, no LOH was detected for the markers evaluated. CONCLUSIONS: M/R and primary TCV have similar cytologic features. Additional studies of larger series of M/R and primary TCV should be performed to delineate further any potential application of LOH for chromosome 1 and the p53 gene as a tool for diagnosing TCV with cytologic preparations. Cancer (Cancer Cytopathol)

Adult↗