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1.
Autoimmun Rev ; 22(1): 103230, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36347462

RESUMEN

Chronic fatigue syndrome (CFS), fibromyalgia, silicone breast implants syndrome (SBIs), COVID and post-COVID syndrome (PCS), sick building syndrome (SBS), post-orthostatic tachycardia syndrome (POTS), autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants (ASIA) are frequently accompanied by clinical symptoms characteristic for dysautonomia: severe fatigue, dizziness, fogginess, memory loss, dry mouth and eyes, hearing dysfunction, tachycardia etc. The recent discovery of an imbalance of autoantibodies against G protein-coupled receptors (GPCR) in some autoimmune diseases, post-COVID syndrome, SBIs allowed researchers to assume the novel mechanism in these conditions - autoimmune autonomic nervous system imbalance. In this review, all data published on an imbalance of autoantibodies against GPCR, clinical symptoms and pathogenic mechanisms in CFS, Fibromyalgia, SBIs, COVID and PCS, SBS, POTS, and some autoimmune diseases were analyzed. Possible criteria to diagnose the autoimmune autonomic nervous system imbalance were created.


Asunto(s)
Enfermedades Autoinmunes , Implantes de Mama , COVID-19 , Síndrome de Fatiga Crónica , Fibromialgia , Disautonomías Primarias , Síndrome del Edificio Enfermo , Humanos , Síndrome de Fatiga Crónica/etiología , Fibromialgia/etiología , Implantes de Mama/efectos adversos , COVID-19/complicaciones , Sistema Nervioso Autónomo , Autoanticuerpos , Taquicardia , Adyuvantes Inmunológicos , Siliconas
2.
Autoimmun Rev ; : 103231, 2022 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-36356798

RESUMEN

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.autrev.2022.103230. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

3.
Cancer Treat Res Commun ; 29: 100489, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34837797

RESUMEN

The modern checkpoint inhibitors block the programmed death-1 receptor and its ligand, cytotoxic T-lymphocyte-associated antigen 4 on tumor cells and lymphocytes, that induces cytotoxic reactions. Nowadays, there are no approved clinical and laboratory predictor markers of immune therapy efficacy, which would allow a more personalized approach to patient selection and treatment. The aim of this review is to analyze possible biomarkers of efficacy for treatment with checkpoint inhibitors according to the pathogenic mechanisms of drug action. The review revealed possible predictive biomarkers, that could be classified to 3 groups: biomarkers of high mutagenic potential of the tumor, biomarkers of high activity of adaptive immunity, biomarkers of low activity of the tumor microenvironment. The determination of the described markers before the start of therapy can be used to formulate a treatment regimen, in which the use of various immunomodulatory drugs, inhibitors of proinflammatory cytokines, angiogenic molecules, and probiotics can be considered.


Asunto(s)
Inmunidad Adaptativa/inmunología , Biomarcadores de Tumor/metabolismo , Inmunoterapia/métodos , Humanos , Microambiente Tumoral
4.
Physiol Res ; 70(3): 383-391, 2021 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-33982577

RESUMEN

The study aimed to contribute to understanding the role of CRP, chemerin, fetuin-A and osteopontin and to assess their suitability as biomarkers of early stages of cardiovascular diseases in psoriasis vulgaris. Serum levels measured in 28 patients and 22 controls. Patients: increased levels of CRP (p<0.001), chemerin (p<0.05), osteopontin (p<0.05) and decreased levels of fetuin-A (p<0.05), significant relationships between CRP and fetuin-A (rho=0.530, p<0.01), CRP and chemerin (rho=0.543, p<0.01), CRP and age (rho=0.590, p<0.001), osteopontin and fetuin-A (r=-0.415, p<0.05), chemerin and PASI score (rho=-0.424, p<0.05). We confirmed specific roles of the biomarkers in psoriasis. CRP, fetuin-A and osteopontin could be considered appropriate markers for the detection of early stages of cardiovascular diseases.


Asunto(s)
Proteína C-Reactiva/análisis , Quimiocinas/sangre , Factores de Riesgo de Enfermedad Cardiaca , Osteopontina/sangre , Psoriasis/complicaciones , alfa-2-Glicoproteína-HS/análisis , Adulto , Biomarcadores , Índice de Masa Corporal , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad
5.
Clin Immunol ; 227: 108724, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33845192

RESUMEN

Sarcoidosis and tuberculosis have many clinical and laboratory similarities, which allowed researchers to assume the presence of common pathogenetic mechanisms in the development of both diseases. Recently, much attention has been paid to investigate the autoimmune origins in these pathologies. The aim of this study is to find out the characteristics of the autoinflammatory immune response in sarcoidosis and tuberculosis. In patients with sarcoidosis (n = 93), tuberculosis (n = 28), and in healthy donors (n = 40), the serum anti-MCV concentration was measured by ELISA, and B cell subpopulations were analyzed by flow cytometry. Based on the results obtained, the formula ([B-naïve%]\[B-memory%]) * ([B-CD38%] + [B-CD5%]) / [anti-MCV] was described. The increase in the calculated index by more than 5 units with a sensitivity of 80.00% and a specificity of 93.10% (AUC = 0.926) suggest the presence of the autoimmune component, which is more typical for sarcoidosis, rather than tuberculosis patients and may serve as a diagnostic criterion.


Asunto(s)
Anticuerpos Antiproteína Citrulinada/inmunología , Autoinmunidad/inmunología , Linfocitos B/inmunología , Inflamación/inmunología , Sarcoidosis Pulmonar/inmunología , Tuberculosis Pulmonar/inmunología , Vimentina/inmunología , Estudios de Casos y Controles , Citrulinación , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Humanos , Memoria Inmunológica , Inmunofenotipificación , Masculino , Estudios Prospectivos
6.
Annu Rev Biochem ; 90: 165-191, 2021 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-33792375

RESUMEN

Double-strand DNA breaks (DSBs) are the most lethal type of DNA damage, making DSB repair critical for cell survival. However, some DSB repair pathways are mutagenic and promote genome rearrangements, leading to genome destabilization. One such pathway is break-induced replication (BIR), which repairs primarily one-ended DSBs, similar to those formed by collapsed replication forks or telomere erosion. BIR is initiated by the invasion of a broken DNA end into a homologous template, synthesizes new DNA within the context of a migrating bubble, and is associated with conservative inheritance of new genetic material. This mode of synthesis is responsible for a high level of genetic instability associated with BIR. Eukaryotic BIR was initially investigated in yeast, but now it is also actively studied in mammalian systems. Additionally, a significant breakthrough has been made regarding the role of microhomology-mediated BIR in the formation of complex genomic rearrangements that underly various human pathologies.


Asunto(s)
Roturas del ADN de Doble Cadena , Reparación del ADN , Replicación del ADN , Mamíferos/genética , Homeostasis del Telómero/genética , Animales , Reparación del ADN por Unión de Extremidades , Humanos , Mutación , Levaduras/genética
8.
Bratisl Lek Listy ; 121(8): 558-564, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32726118

RESUMEN

BACKGROUND: Goeckerman therapy (GT) of psoriasis involves dermal application of crude coal tar containing polycyclic aromatic hydrocarbons (PAHs) and exposure to ultraviolet radiation (UVR). Little is known about GT influence on DNA epigenetics. OBJECTIVE: The study aim was to discover epigenetic mechanisms altered by the exposure related to the GT of psoriasis. METHODS: Observed group of patients with plaque psoriasis (n = 23) was treated by GT with 3 % CCT. Before and after GT, we analyzed the levels of benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts (BPDE-DNA), p53 protein in serum, 5-methylcytosine (5-mC, global DNA methylation), and methylation in selected CpG sites of p53 gene. RESULTS: We found a significant increase in the levels of BPDE-DNA (p < 0.01) and serum levels of p53 protein (p < 0.01) after GT, and an insignificant decrease in the percentage of 5-mC in peripheral blood DNA. Methylation of p53 CpG sites was affected neither by psoriasis nor by GT. The study confirmed good effectiveness of GT (significantly reduced psoriasis area and severity index; p < 0.001). CONCLUSION: Our findings indicate that there is a significantly increased genotoxic hazard related to the exposure of PAHs and UV radiation after GT of psoriasis. However, global DNA methylation and p53 gene methylation evade the effect of GT, as they remained unchanged (Tab. 4, Fig. 3, Ref. 50).


Asunto(s)
Epigénesis Genética , Hidrocarburos Policíclicos Aromáticos , Psoriasis , Terapia Ultravioleta , Daño del ADN , Epigénesis Genética/efectos de los fármacos , Humanos , Hidrocarburos Policíclicos Aromáticos/efectos adversos , Hidrocarburos Policíclicos Aromáticos/uso terapéutico , Psoriasis/terapia , Rayos Ultravioleta , Terapia Ultravioleta/efectos adversos
9.
Sci Rep ; 10(1): 1059, 2020 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-31974463

RESUMEN

Sarcoidosis is a systemic granulomatous disease that develops due to the Th1, Th17 and Treg lymphocytes disturbance. There is an assumption, that B cells and follicular T-helper (Tfh) cells may play an important role in this disorder, as well as in several other autoimmune diseases. The aim of this study was to determine CD19+ B cells subset distribution in the peripheral blood and to define disturbance in the circulating Tfh cells subsets in patients with sarcoidosis. The prospective comparative study was performed in 2016-2018, where peripheral blood B cell subsets and circulating Tfh cell subsets were analyzed in 37 patients with primarily diagnosed sarcoidosis and 35 healthy donors using multicolor flow cytometry. In the results of our study we found the altered distribution of peripheral B cell subsets with a predominance of "naïve" (IgD + CD27-) and activated B cell (Bm2 and Bm2') subsets and a decreased frequency of memory cell (IgD+ CD27+ and IgD- CD27+) in peripheral blood of sarcoidosis patients was demonstrated. Moreover, we found that in sarcoidosis patients there are increased levels of B cell subsets, which were previously shown to display regulatory capacities (CD24+++ CD38+++ and CD5 + CD27-). Next, a significantly higher proportion of CXCR5-expressing CD45RA - CCR7+ Th cells in patients with sarcoidosis in comparison to the healthy controls was revealed, that represents the expansion of this memory Th cell subset in the disease. This is the first study to demonstrate the association between the development of sarcoidosis and imbalance of circulating Tfh cells, especially CCR4- and CXCR3-expressing Tfh subsets. Finally, based on our data we can assume that B cells and Tfh2- and Tfh17-like cells - most effective cell type in supporting B-cell activity, particularly in antibody production - may be involved in the occurrence and development of sarcoidosis and in several other autoimmune conditions. Therefore, we can consider these results as a new evidence of the autoimmune mechanisms in the sarcoidosis development.


Asunto(s)
Subgrupos de Linfocitos B/citología , Sarcoidosis Pulmonar/sangre , Linfocitos T Colaboradores-Inductores/citología , Adulto , Subgrupos de Linfocitos B/inmunología , Femenino , Citometría de Flujo , Humanos , Recuento de Linfocitos , Masculino , Estudios Prospectivos , Sarcoidosis Pulmonar/diagnóstico , Sarcoidosis Pulmonar/inmunología , Linfocitos T Colaboradores-Inductores/inmunología
10.
Trends Genet ; 34(7): 518-531, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29735283

RESUMEN

Break-induced replication (BIR) is a pathway that repairs one-ended double-strand breaks (DSBs). For decades, yeast model systems offered the only opportunities to study eukaryotic BIR. These studies described an unusual mode of BIR synthesis that is carried out by a migrating bubble and shows conservative inheritance of newly synthesized DNA, leading to genomic instabilities like those associated with cancer in humans. Yet, evidence of BIR functioning in mammals or during repair of other DNA breaks has been missing. Recent studies have uncovered multiple examples of BIR working in replication restart and repair of eroded telomeres in yeast and mammals, as well as some unexpected findings, including the RAD51 independence of BIR. Strong interest remains in determining the variations in molecular mechanisms that drive and regulate BIR in different genetic backgrounds, across organisms, and particularly in the context of human disease.


Asunto(s)
Reparación del ADN/genética , Replicación del ADN/genética , Animales , Roturas del ADN de Doble Cadena , Inestabilidad Genómica/genética , Humanos , Recombinación Genética/genética , Telómero/genética
11.
Radiat Res ; 189(4): 389-398, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29373091

RESUMEN

The research for high-throughput diagnostic tests for victims of radio/nuclear incidents remains ongoing. In this context, we have previously identified candidate genes that predict risk of late-occurring hematologic acute radiation syndrome (HARS) in a baboon model. The goal of the current study was to validate these genes after radiation exposure in humans. We also examined ex vivo relative to in vivo measurements in both species and describe dose-response relationships. Eighteen baboons were irradiated in vivo to simulate different patterns of partial- or total-body irradiation (TBI), corresponding to an equivalent dose of 2.5 or 5 Sv. Human in vivo blood samples were obtained from patients exposed to different dose ranges: diagnostic computerized tomography (CT; 0.004-0.018 Sv); radiotherapy for prostate cancer (0.25-0.3 Sv); and TBI of leukemia patients (2 × 1.5 or 2 × 2 Sv, five patients each). Peripheral whole blood of another five baboons and human samples from five healthy donors were cultivated ex vivo and irradiated with 0-4 Sv. RNA was isolated pairwise before and 24 h after irradiation and converted into cDNA. Gene expression of six promising candidate genes found previously by us in a baboon model ( WNT3, POU2AF1, CCR7, ARG2, CD177, WLS), as well as three genes commonly used in ex vivo whole blood experiments ( FDXR, PCNA, DDB2) was measured using qRT-PCR. We confirmed the six baboon candidate genes in leukemia patients. However, expression for the candidate gene FDXR showed an inverse relationship, as it was downregulated in baboons and upregulated in human samples. Comparisons among the in vivo and ex vivo experiments revealed the same pattern in both species and indicated peripheral blood cells to represent the radiation-responsive targets causing WNT3 and POU2AF1 gene expression changes. CCR7, ARG2, CD177 and WLS appeared to be altered due to radiation-responsive targets other than the whole blood cells. Linear dose-response relationships of FDXR, WNT3 and POU2AF1 using human ex vivo samples corresponded with human in vivo samples, suggesting that ex vivo models for in vivo dose estimates can be used over a wide dose range (0.001-5 Sv for POU2AF1). In summary, we validated six baboon candidate genes in humans, but the FDXR measurements underscored the importance of independent assessments even when candidates from animal models have striking gene sequence homology to humans. Since whole blood cells represented the same radiation-responsive targets for FDXR, WNT3 and POU2AF1 gene expression changes, ex vivo cell culture models can be utilized for in vivo dose estimates over a dose range covering up to 3.5 log scales. These findings might be a step forward in the development of a gene expression-based high-throughput diagnostic test for populations involved in large-scale radio/nuclear incidents.


Asunto(s)
Papio , Transcriptoma/efectos de la radiación , Adulto , Anciano , Anciano de 80 o más Años , Animales , Relación Dosis-Respuesta en la Radiación , Humanos , Masculino , Persona de Mediana Edad , Especificidad de la Especie , Irradiación Corporal Total
12.
Artículo en Ruso | MEDLINE | ID: mdl-18196637

RESUMEN

A role of ethnic and social aspects of risk factors for stroke has been studied in 210 patients born in ethnically homogenous marriages. Patients were recruited from the main ethnic groups of Izhevsk, i.e. Russian, Udmurt and Tartar. Between-ethnic differences in the prevalence of social and cultural factors conferring the risk for stroke have been found. In particular, these factors dominated in Udmurt patients.


Asunto(s)
Etnicidad , Accidente Cerebrovascular/etnología , Población Urbana/estadística & datos numéricos , Adulto , Distribución por Edad , Anciano , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Federación de Rusia/epidemiología , Distribución por Sexo , Factores Socioeconómicos
13.
Artículo en Ruso | MEDLINE | ID: mdl-16447558

RESUMEN

To study hereditary predisposition to stroke in main ethnic groups of Izhevsk, 210 patients born in ethnically homogenous marriages have been examined and the data on state of health of 1701 relatives over 40 years old have been obtained. A role of hereditary factor in development of stroke was revealed. Also, there were ethnic differences related to a prevalence of carbohydrate-lipid metabolism disorder in patients of the Tartar group comparing to Udmurt and Russians.


Asunto(s)
Accidente Cerebrovascular/etnología , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Baskiria/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Federación de Rusia/etnología , Distribución por Sexo
14.
Curr Biol ; 11(13): 1053-7, 2001 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-11470411

RESUMEN

Saccharomyces cells with a single unrepaired double-strand break (DSB) will adapt to checkpoint-mediated G2/M arrest and resume cell cycle progression. The decision to adapt is finely regulated by the extent of single-stranded DNA generated from a DSB. We show that cells lacking the recombination protein Tid1p are unable to adapt, but that this defect is distinct from any role in recombination. As with the adaptation-defective mutations yku70Delta and cdc5-ad, permanent arrest in tid1Delta is bypassed by the deletion of the checkpoint gene RAD9. Permanent arrest of tid1Delta cells is suppressed by the rfa1-t11 mutation in the ssDNA binding complex RPA, similar to yku70Delta, whereas the defect in cdc5-ad is not suppressed. Unlike yku70Delta, tid1Delta does not affect 5'-to-3' degradation of DSB ends. The tid1Delta defect cannot be complemented by overexpressing the homolog Rad54p, nor is it affected in rad51Delta tid1Delta, rad54Delta tid1Delta, or rad52Delta tid1Delta double mutants that prevent essentially all homologous recombination. We suggest that Tid1p participates in monitoring the extent of single-stranded DNA produced by resection of DNA ends in a fashion that is distinct from its role in recombination.


Asunto(s)
Adaptación Fisiológica , Antígenos Nucleares , Daño del ADN , ADN Helicasas , Proteínas Fúngicas/fisiología , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Enzimas Reparadoras del ADN , ADN de Hongos/genética , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/genética , Fase G2 , Eliminación de Gen , Cinética , Autoantígeno Ku , Mitosis , Proteínas Nucleares/genética , Saccharomyces cerevisiae/citología
15.
Genes Dev ; 15(9): 1055-60, 2001 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-11331601

RESUMEN

Without the RAD51 strand exchange protein, Saccharomyces cerevisiae cannot repair a double-strand break (DSB) by gene conversion. However, cells can repair DSBs by recombination-dependent, break-induced replication (BIR). RAD51-independent BIR is initiated more than 13 kb from the DSB. Repair depends on a 200-bp sequence adjacent to ARS310, located approximately 34 kb centromere-proximal to the DSB, but does not depend on the origin activity of ARS310. We conclude that the ability of a recombination-induced replication fork to copy > 130 kb to the end of the chromosome depends on a special site that enhances assembly of a processive repair replication fork.


Asunto(s)
Cromosomas Fúngicos , Reparación del ADN/fisiología , Proteínas de Unión al ADN/metabolismo , Elementos de Facilitación Genéticos , Secuencia de Bases , Replicación del ADN , Proteínas de Unión al ADN/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Datos de Secuencia Molecular , Recombinasa Rad51 , Recombinación Genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae
16.
Mol Cell Biol ; 21(6): 2048-56, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11238940

RESUMEN

Broken chromosomes can be repaired by several homologous recombination mechanisms, including gene conversion and break-induced replication (BIR). In Saccharomyces cerevisiae, an HO endonuclease-induced double-strand break (DSB) is normally repaired by gene conversion. Previously, we have shown that in the absence of RAD52, repair is nearly absent and diploid cells lose the broken chromosome; however, in cells lacking RAD51, gene conversion is absent but cells can repair the DSB by BIR. We now report that gene conversion is also abolished when RAD54, RAD55, and RAD57 are deleted but BIR occurs, as with rad51Delta cells. DSB-induced gene conversion is not significantly affected when RAD50, RAD59, TID1 (RDH54), SRS2, or SGS1 is deleted. Various double mutations largely eliminate both gene conversion and BIR, including rad51Delta rad50Delta, rad51Delta rad59Delta, and rad54Delta tid1Delta. These results demonstrate that there is a RAD51- and RAD54-independent BIR pathway that requires RAD59, TID1, RAD50, and presumably MRE11 and XRS2. The similar genetic requirements for BIR and telomere maintenance in the absence of telomerase also suggest that these two processes proceed by similar mechanisms.


Asunto(s)
Reparación del ADN/genética , Proteínas de Unión al ADN/genética , ADN/genética , Proteínas Fúngicas/genética , Proteínas de Saccharomyces cerevisiae , Cromosomas Fúngicos , ADN Helicasas/genética , ADN Helicasas/metabolismo , Enzimas Reparadoras del ADN , Replicación del ADN/genética , ADN-Topoisomerasas , Proteínas de Unión al ADN/metabolismo , Desoxirribonucleasas de Localización Especificada Tipo II/genética , Desoxirribonucleasas de Localización Especificada Tipo II/metabolismo , Proteínas Fúngicas/metabolismo , Conversión Génica , Eliminación de Gen , Recombinasa Rad51 , RecQ Helicasas , Saccharomyces cerevisiae/genética
17.
Proc Natl Acad Sci U S A ; 97(26): 14500-5, 2000 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-11121053

RESUMEN

In meiosis, gene conversions are accompanied by higher levels of crossing over than in mitotic cells. To determine whether the special properties of meiotic recombination can be attributed to the way in which Spo11p creates double-strand breaks (DSBs) at special hot spots in Saccharomyces cerevisiae, we expressed the site-specific HO endonuclease in meiotic cells. We could therefore compare HO-induced recombination in a well-defined region both in mitosis and meiosis, as well as compare Spo11p- and HO-induced meiotic events. HO-induced gene conversions in meiosis were accompanied by crossovers at the same high level (52%) as Spo11p-induced events. Moreover, HO-induced crossovers were reduced 3-fold by a msh4Delta mutation that similarly affects Spo11p-promoted events. In a spo11Delta diploid, where the only DSB is made by HO, crossing over was significantly higher (27%) than in mitotic cells (

Asunto(s)
Proteínas de Unión al ADN , Desoxirribonucleasas de Localización Especificada Tipo II/metabolismo , Esterasas/metabolismo , Meiosis/fisiología , Recombinación Genética , Proteínas de Saccharomyces cerevisiae , Cromátides , Intercambio Genético , ADN-Topoisomerasas de Tipo II/genética , ADN-Topoisomerasas de Tipo II/metabolismo , Desoxirribonucleasas de Localización Especificada Tipo II/genética , Endodesoxirribonucleasas , Esterasas/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Conversión Génica , Mitosis/fisiología , Saccharomyces cerevisiae/genética
19.
Proc Natl Acad Sci U S A ; 94(13): 6851-6, 1997 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-9192655

RESUMEN

To study targeted recombination, a single linear 2-kb fragment of LEU2 DNA was liberated from a chromosomal site within the nucleus of Saccharomyces cerevisiae, by expression of the site-specific HO endonuclease. Gene targeting was scored by gene conversion of a chromosomal leu2 mutant allele by the liberated LEU2 fragment. This occurred at a frequency of only 2 x 10(-4), despite the fact that nearly all cells successfully repaired, by single-strand annealing, the chromosome break created by liberating the fragment. The frequency of Leu+ recombinants was 6- to 25-fold higher in pms1 strains lacking mismatch repair. In 70% of these cases, the colony was sectored for Leu+/Leu-. Similar results were obtained when a 4. 1-kb fragment containing adjacent LEU2 and ADE1 genes was liberated, to convert adjacent leu2 and ade1 mutations on the chromosome. These results suggest that a linear fragment is not assimilated into the recipient chromosome by two crossovers each close to the end of the fragment; rather, heteroduplex DNA between the fragment and the chromosome is apparently formed over the entire region, by the assimilation of one of the two strands of the linear duplex DNA. Moreover, the recovery of Leu+ transformants is frequently defeated by the cell's mismatch repair machinery; more than 85% of mismatches in heteroduplex DNA are corrected in favor of the resident, unbroken (mutant) strand.


Asunto(s)
Oxidorreductasas de Alcohol/genética , ADN de Cadena Simple/genética , ADN/genética , Marcación de Gen , Recombinación Genética , 3-Isopropilmalato Deshidrogenasa , Saccharomyces cerevisiae/genética
20.
Probl Tuberk ; (4): 8-9, 1997.
Artículo en Ruso | MEDLINE | ID: mdl-9333827

RESUMEN

The antituberculosis measures made have achieved their peak efficiency and, if specific measures to increase the detection rates of patients in the general population and the level of vaccination cannot be found now, tuberculosis morbidity rates cannot be expected to become lower in the near future. This is evidenced by the 1996 prognosis that the morbidity will rise from 84.6 to 96.1 per 10,000 persons. It is expedient to implement preventive antituberculosis measures, by taking into account the regional features of a specific area.


Asunto(s)
Antituberculosos/uso terapéutico , Tuberculosis/prevención & control , Adulto , Niño , Humanos , Morbilidad/tendencias , Estudios Retrospectivos , Federación de Rusia/epidemiología , Tuberculosis/epidemiología
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