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1.
Rhinology ; 61(4): 312-319, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37243690

RESUMEN

STATEMENT OF PROBLEM: Evaluating the effectiveness of the management of Olfactory Dysfunction (OD) has been limited by a paucity of high-quality randomised and/or controlled trials. A major barrier is heterogeneity of outcomes in such studies. Core outcome sets (COS) - standardized sets of outcomes that should be measured/reported as determined by consensus-would help overcome this problem and facilitate future meta-analyses and/or systematic reviews (SRs). We set out to develop a COS for interventions for patients with OD. METHODS: A long-list of potential outcomes was identified by a steering group utilising a literature review, thematic analysis of a wide range of stakeholders' views and systematic analysis of currently available Patient Reported Outcome Measures (PROMs). A subsequent e-Delphi process allowed patients and healthcare practitioners to individually rate the outcomes in terms of importance on a 9-point Likert scale. RESULTS: After 2 rounds of the iterative eDelphi process, the initial outcomes were distilled down to a final COS including subjective questions (visual analogue scores, quantitative and qualitative), quality of life measures, psychophysical testing of smell, baseline psychophysical testing of taste, and presence of side effects along with the investigational medicine/device and patient's symptom log. CONCLUSIONS: Inclusion of these core outcomes in future trials will increase the value of research on clinical interventions for OD. We include recommendations regarding the outcomes that should be measured, although future work will be required to further develop and revalidate existing outcome measures.


Asunto(s)
Trastornos del Olfato , Calidad de Vida , Humanos , Proyectos de Investigación , Técnica Delphi , Determinación de Punto Final , Evaluación de Resultado en la Atención de Salud , Trastornos del Olfato/diagnóstico , Trastornos del Olfato/terapia , Resultado del Tratamiento
2.
Nucl Med Biol ; 41(9): 744-8, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25037755

RESUMEN

INTRODUCTION: Noninvasive radionuclide imaging of cells using technetium99m-hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) is a potential diagnostic tool for several applications. Herein we aimed to evaluate the labeling efficiency and cellular toxicity of (99m)Tc-HMPAO with Stromal Vascular Fraction (SVF) of adipose tissue to develop a process tool for theranostic purposes, in particular imaging cardiac stem cell therapy. METHODS: Ten million cells of SVF were labeled with (99m)Tc-HMPAO complex and excess radiolabel was cleared off through washing in PBS. The labeling efficiency of (99m)Tc-HMPAO was detected in labeled cells and their subsequent supernatant wash using isotope dose calibrator and gamma camera. The cytotoxicity was assessed for the comparative reactive oxygen species (ROS) by H2DCFDDA, apoptotic events by annexin-V and TUNEL assay and mitochondrial potential by JC-1. RESULTS: An encouraging labeling efficiency of 33% was observed with (99m)Tc-HMPAO complex. The radionuclide labeling of SVF demonstrated significant safety profile as evaluated by apoptotic assays. CONCLUSION: (99m)Tc-HMPAO labeling efficiency of 33% of total SV fraction would produce sufficient radioactive signals that would enable for in vivo tracking of cells by SPECT-CT. The radionuclide did not demonstrate any significant impact on the structural or functional organization of the labeled cells. Our study indicates that SVF can be safely labeled with (99m)Tc-HMPAO without adverse cytotoxic events and for its potential role in imaging cardiac stem cell therapy.


Asunto(s)
Tejido Adiposo/citología , Tejido Adiposo/efectos de la radiación , Rastreo Celular/métodos , Exametazima de Tecnecio Tc 99m/farmacología , Tejido Adiposo/fisiología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Humanos , Dosis de Radiación , Cintigrafía , Radiofármacos/síntesis química , Radiofármacos/farmacología , Coloración y Etiquetado , Células del Estroma/diagnóstico por imagen , Células del Estroma/efectos de los fármacos , Células del Estroma/fisiología , Exametazima de Tecnecio Tc 99m/química
3.
Colloids Surf B Biointerfaces ; 112: 255-63, 2013 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-23994749

RESUMEN

In this present study, we investigated thio glycolic acid-capped cadmium telluride quantum dots (TGA-CdTe QDs) as nano carrier to study the antiarthritic activity of quercetin on adjuvant induced arthritic Wistar rats. The free radical scavenging activity of QDs-QE complex was evaluated by 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and superoxide anion scavenging assays. Fifteen days after adjuvant induction, arthritic rats received QDs-QE complex orally at the dose of 0.2 and 0.4mg/kg daily for 3 weeks. Diclofenac sodium (DF) was used as a reference drug. Administration of QDs-QE complex showed a significant reduction in inflammation and improvement in cartilage regeneration. Treatment with QDs-QE complex significantly (P<0.05) reduced the expressions lipid peroxidation and showed significant (P<0.05) increase in activities of antioxidant enzymes such as superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) catalase (CAT) levels in paw tissue. C-reactive protein (CRP), rheumatoid factor (RF), red blood cells (RBC) and white blood cells (WBC) count and erythrocyte sedimentation rate (ESR) of experimental animals were also estimated. Histology of hind limb tissue in experimental groups confirmed the complete cartilage regeneration in arthritis induced rats treated with QDs-QE complex. Based on our findings, we suggest that the QDs act as nano carrier for the drugs used in the treatment of various degenerative diseases.


Asunto(s)
Artritis Experimental/tratamiento farmacológico , Compuestos de Cadmio/química , Puntos Cuánticos/química , Quercetina/administración & dosificación , Telurio/química , Tioglicolatos/química , Animales , Antioxidantes/administración & dosificación , Artritis Experimental/sangre , Artritis Experimental/patología , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos , Femenino , Tamaño de la Partícula , Puntos Cuánticos/ultraestructura , Ratas , Ratas Wistar , Espectrofotometría
4.
ISRN Biotechnol ; 2013: 528708, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-25969775

RESUMEN

The optimization of extracellular lipase production by Fusarium isolani strain SKWF7 isolated from dairy wastewater was carried out in this study. Initially, the physicochemical factors significantly influencing enzyme production were studied by varying one-factor-at-a-time (OFAT). A mesophilic temperature of 40°C, alkaline pH of 8, and incubation period of 72 hours were found to be the optimal conditions for lipase production. Among the media components, the disaccharide sucrose acted as the best carbon source; palm oil as the best inducing lipid substrate; casein and (NH4)2SO4 as the best organic and inorganic nitrogen sources; Ca(2+) ion as the best trace element. In the next phase of work, statistical optimization of medium components was performed by employing the Box-Behnken design of Response Surface Methodology (RSM). The optimum concentrations of three significant factors, namely, palm oil, (NH4)2SO4, and CaCO3 were determined by this method to be 5% (v/v), 5.5 g/L, and 0.1 g/L, respectively. RSM-guided design of experiments resulted in a maximum lipase production of 73.3 U/ml, which is a 1.7-fold increase in comparison with that obtained in the unoptimized medium. These results point towards the success of the model in developing a process for the production of lipase, an enzyme of enormous industrial significance.

6.
J Cardiovasc Dis Res ; 2(2): 133-6, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21814420

RESUMEN

A 62-year-old male patient with previous history of myocardial infarction, akinetic myocardial segments, and an ejection fraction of 31% with the NYHA class III category was selected for the autologous bone marrow (ABM)-derived mononuclear cell fraction injection during CABG surgery. Nitrate augmented myocardial tracer uptake was imaged by ECG gated SPECT pre- and 1 year post-ABM therapy, using radiotracer Tc99m Sestamibi. The baseline gated SPECT demonstrated full thickness infarct in 40% area of LAD territory. Bone marrow aspirate of 20.0 ml from sternum yielding a mono nuclear cell fraction of 4.5 × 10(7) cells/ml was suspended in 2.0 ml of sterile normal saline to be injected at eight sites of the injured myocardium. There were no apparent side effects due to the procedure, i.e., life threatening events, major bleeds, reaction, or shock. The case was followed at the end of 1, 3, 6 months by ECG and Holter monitor and ECG gated SPECT at the end of 12 months. The gated SPECT images demonstrated mild but definitely improved tracer uptake within part of the infarcted segments along with improvement in ejection fraction to 45%, and a clinical change in the NYHA Class to II. Cell-based therapy may offer benefits of induction of normal tissue microenvironment.

7.
Diagn Pathol ; 5: 83, 2010 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-21176184

RESUMEN

BACKGROUND: To evaluate the diagnostic utility of alpha-methylacyl CoA racemase (P504S) & HMWCK (34beta E12) in morphologically difficult prostate cancer. METHODS: A total of 1034 cases were reviewed and divided into benign (585) malignant (399) and suspicious (50). Immunohistochemistry with HMWCK and AMACR was done on the 50 suspicious cases along with controls. RESULTS: Forty nine suspicious cases were resolved by using both markers where as 1 case was resolved by further support with CD68. The original diagnosis was changed in 15 of 50 (30%) suspicious cases from benign to malignant, one case from benign to high grade PIN and in one case from malignant to benign. Change of diagnosis was seen in 17 of 50 (34%) suspicious cases with a significant p value of 0.002. The overall diagnosis was changed in 17 of 1034 cases (1.64%) of prostatic disease (p < 0.001). CONCLUSIONS: A combination of HMWCK and AMACR is of great value in combating the morphologically suspicious cases and significantly increasing the diagnostic accuracy in prostate cancer. Although, in this study the sensitivity and specificity of HMWCK and AMACR were high, yet it should be used with caution, keeping in mind all their pitfalls and limitations.


Asunto(s)
Biomarcadores de Tumor/análisis , Carcinoma/enzimología , Queratinas/análisis , Neoplasias de la Próstata/enzimología , Racemasas y Epimerasas/análisis , Anciano , Anciano de 80 o más Años , Biopsia , Carcinoma/patología , Carcinoma/cirugía , Estudios de Casos y Controles , Humanos , Inmunohistoquímica , India , Masculino , Persona de Mediana Edad , Peso Molecular , Valor Predictivo de las Pruebas , Prostatectomía , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/cirugía , Sensibilidad y Especificidad
8.
Cell Transplant ; 19(4): 409-18, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20447340

RESUMEN

Liver transplantation is the only existing modality for treating decompensated liver cirrhosis. Several factors, such as nonavailability of donors, combined with operative risks, complications associated with rejection, usage of immunosuppressive agents, and cost intensiveness, make this strategy available to only a few people. With a tremendous upsurge in the mortality rate of patients with liver disorders worldwide, there is a need to search for an alternative therapeutic tool that can combat the above limitations and serve as a supportive therapy in the management of liver diseases. Cell therapy using human fetal liver-derived stem cells can provide great potential to conservatively manage end-stage liver diseases. Therefore, the present investigation aimed to study and prove the safety and efficacy of human fetal liver-derived stem cell transplantation in patients with end-stage liver cirrhosis. Twenty-five patients with liver cirrhosis of different etiologies were infused with human fetal liver-derived stem cells (EpCAM+ve) labeled with Tc-HMPAO through hepatic artery. Our high throughput analysis using flow cytometry, RT-PCR, and cellular characterization exemplifies fetal liver cells with their high proliferation rate could be the best source for rejuvenating the diseased liver. Further, no episodes related to hepatic encephalopathy recurred in any of the subjects following hepatic stem cell transplantation. There was marked clinical improvement observed in terms of all clinical and biochemical parameters. Further, there was decrease in mean MELD score (p < 0.01) observed in 6 months follow-up in all patients. Therapy using human fetal liver stem/progenitor cells offers a potentially supportive modality to organ transplantation in the management of liver diseases.


Asunto(s)
Células Madre Fetales/trasplante , Cirrosis Hepática/terapia , Hígado/citología , Adulto , Biomarcadores/metabolismo , Tratamiento Basado en Trasplante de Células y Tejidos , Células Madre Fetales/citología , Citometría de Flujo , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Trasplante de Células Madre , Exametazima de Tecnecio Tc 99m
9.
J Assoc Physicians India ; 56: 503-7, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18846900

RESUMEN

OBJECTIVE: Widely prevalent vitamin D deficiency and delayed diagnosis contributes to severe symptomatic primary hyperparathyroidism in India. We analysed fifty one consecutive patients of primary hyperparathyroidism managed at our centre. All of them were symptomatic. DESIGN: Retrospective analysis. MATERIAL AND METHODS: Fifty one consecutive cases of symptomatic primary hyperparathyroidism, presenting to our centre from January 1994 to May 2007 were retrospectively analyzed. Clinical presentation, biochemical, radiological and details of underlying parathyroid lesion were noted. RESULTS: A total of 51 cases of primary hyperparathyroidism were studied. Mean age was 39.5 +/- 11.5 yrs (Range 13 to 70 years, Female: Male 2:1). Mean duration of symptoms was 35.8 + 29.1 months. Bone pains and painful proximal myopathy were the commonest presentation (24/51), followed by pathological fractures in 12 cases. Distal Renal tubular acidosis was diagnosed in 4 cases, 3 of whom normalized after surgery. At initial evaluation, twenty one patients had elevated alkaline phosphatase with normal calcium levels indirectly suggesting associated vitamin D deficiency. Low serum levels of 25-hydroxy vitamin D were documented in five of them. Parathyroid carcinoma was diagnosed in 3 patients. Ectopic parathyroid adenoma was seen in 7 cases (3 mediastinal, 3 intrathyroidal, 1 near left carotid sheath). All the cases responded well to surgical excision. CONCLUSION: Lack of universal screening for hypercalcemia, normocalcemia contributed by associated vitamin D deficiency and lack of awareness about unusual presentations of primary hyperparathyroidism led to delayed diagnosis in our patients. Delayed diagnosis and associated vitamin D deficiency in our patients contributed to greater severity of symptomatic primary hyperparathyroidism.


Asunto(s)
Acidosis Tubular Renal , Hiperparatiroidismo Primario/epidemiología , Deficiencia de Vitamina D/epidemiología , Adolescente , Adulto , Anciano , Femenino , Humanos , Hipercalcemia/complicaciones , Hiperparatiroidismo Primario/diagnóstico , Hiperparatiroidismo Primario/etiología , India/epidemiología , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Factores de Riesgo , Deficiencia de Vitamina D/complicaciones
10.
J Assoc Physicians India ; 55: 515-8, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17907504

RESUMEN

Primary Hyperparathyroidism is known to present with protean manifestations leading to misdiagnosis in the initial stages of the disease. Inability to locate the adenoma in an ectopic parathyroid gland may further delay the diagnosis of these cases. Aberrant migration during development may lead to intrathyroidal or other ectopic locations of parathyroid glands. This may lead to their misdiagnosis as a thyroid nodule or failure to locate parathyroids during surgery. Similarity in cytological picture between thyroids and parathyroids may further complicate diagnosis by fine needle aspiration cytology. Nuclear imaging scintigraphy accurately localizes the tumor in 90% of cases and simplifies the surgical management. We encountered three such cases with the parathyroid gland adenomas in ectopic locations in which pre-operative nuclear imaging played a major role.


Asunto(s)
Hiperparatiroidismo Primario/diagnóstico , Glándulas Paratiroides/patología , Neoplasias de las Paratiroides/diagnóstico , Adulto , Diagnóstico Diferencial , Femenino , Humanos , Hiperparatiroidismo Primario/patología , Persona de Mediana Edad , Neoplasias de las Paratiroides/patología
12.
J Carcinog ; 6: 1, 2007 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-17257433

RESUMEN

BACKGROUND: A majority of primary ovarian neoplasms arise from cell surface epithelium of the ovaries. Although old age and a positive family history are associated risk factors, the etiology of the epithelial ovarian tumors is not completely understood. Additionally, knowledge of factors involved in the histogenesis of the various subtypes of this tumor as well as those factors that promote progression to advanced stages of ovarian malignancy are largely unknown. Current evidence suggests that mitochondrial alterations involved in cellular signaling pathways may be associated with tumorigenesis. METHODS: In this study, we determined the presence of polymorphisms and other sequence variants of mitochondrial DNA (mtDNA) in 102 epithelial ovarian tumors including 10 matched normal tissues that paired with some of the tumors. High-resolution restriction endonucleases and PCR-based sequencing were used to assess the mtDNA variants spanning 3.3 kb fragment that comprised the D-Loop and 12S rRNA-tRNAphe, tRNAval, tRNAser, tRNAasp, tRNAlys, ATPase 6, ATPase 8, cytochrome oxidase I and II genes. RESULTS: Three hundred and fifty-two (352) mtDNA sequence variants were identified, of which 238 of 352 (68%) have not been previously reported. There were relatively high frequencies of three mutations in the 12S rRNA gene at np 772, 773, and 780 in stage IIIC endometrioid tumors, two of which are novel (773delT and 780delC), and occurred with a frequency of 100% (7/7). Furthermore, two mutations were observed in serous tumors only at np 1657 in stage IV (10/10), and at np 8221delA in benign cystadenomas (3/3) and borderline tumors (4/4). A high frequency, 81% (13/16) of TC insertion at np 310 was found only in early stages of serous subtype (benign cystadenomas, 3/3; borderline tumors, 4/4; stage I tumors, 2/5 and matched normal tissues 4/4). CONCLUSION: Our findings indicate that certain mtDNA mutations can reliably distinguish the different histologic subtypes of epithelial ovarian tumors. In addition, these data raise the possibility that certain mtDNA mutations may be useful biomarkers for predicting tumor aggressiveness and may play a potential role in tumorigenesis.

13.
AIDS Res Ther ; 3: 28, 2006 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-17059603

RESUMEN

BACKGROUND: HLA-G gene is a non-classical MHC class 1 molecule that is highly expressed in the trophoblast at the maternal-fetal interface. In an attempt to elucidate possible immunological mechanisms facilitating protection of infants born to human immunodeficiency virus type (HIV-1) infected mothers, we have been studying genetic variations in the coding and untranslated regions of HLA-G antigen between HIV-1-infected mothers and their infected or uninfected infants. This study investigated whether HLA-G DNA sequence variants are associated with perinatal HIV-1 transmission. RESULTS: Genomic DNA samples were obtained from a nested case-control study of 34 mother-child pairs co-enrolled in a cohort of the Perinatal AIDS Collaborative Transmission Study in New York. The samples were from two groups predominantly of African-American and Hispanic origin: In the first group, both mother and child were HIV-1-infected; in the second group, only the mother was infected while the child remained uninfected. Genotyping of HLA-G gene were performed on the extracted DNA from peripheral blood mononuclear cells using PCR based sequencing and restriction fragment-length polymorphism analyses. Among the studied HLA-G exons, dissimilarities in HLA-G DNA sequence variants between the HIV-1 non-transmitting mother child pairs were mostly observed in exon 8-3'-untranslated region at nucleotide positions T3742A, C3743T, G3777C (P = 0.001). Non-transmitting HIV-1 mother child pairs exhibited dissimilarities at nucleotide position C3743T allele with decreased risk of perinatal HIV-1 transmission, compared with HIV-1 transmitting mother-child pairs carrying this allele (odds ratio 0.02 [95% confidence interval 0.00-0.15] P = 0.00001). In addition, heterozygous dissimilarities at nucleotide positions C634G and 714 insT/G in the 5'-upstream regulatory region were observed between the mother child pairs of the HIV-1-non-transmitting group while homozygous similarities of C634C, and either 714insG/G or mother-child pairs with similar 714insT/G were observed among the transmitting group in the same region. CONCLUSION: This study identified new variants in the HLA-G gene and provides further evidence that dissimilarities in the HLA-G DNA sequence variants could influence the transmission of HIV-1 from infected mothers to their infants.

14.
Biochemistry ; 40(24): 7025-34, 2001 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-11401546

RESUMEN

Repair of DNA interstrand cross-links is a complex process critical to which is the identification of sites of damage by specific proteins. We have recently identified the structural protein nonerythroid alpha spectrin (alphaSpIISigma) as a component of a nuclear protein complex in normal human cells which is involved in the repair of DNA interstrand cross-links and have shown that it forms a complex with the Fanconi anemia proteins FANCA, FANCC, and FANCG. Using DNA affinity chromatography, we now show that alphaSpIISigma, present in HeLa cell nuclei, specifically binds to DNA containing psoralen interstrand cross-links and that the FANCA, FANCC, and FANCG proteins are bound to this damaged DNA as well. That spectrin binds directly to the cross-linked DNA has been shown using purified bovine brain spectrin (alphaSpIISigma1/betaSpIISigma1)2. Binding of the Fanconi anemia (FA) proteins to the damaged DNA may be either direct or indirect via their association with alphaSpIISigma. These results demonstrate a role for alpha spectrin in the nucleus as well as a new function for this protein in the cell, an involvement in DNA repair. alphaSpIISigma may bind to cross-linked DNA and act as a scaffold to help in the recruitment of repair proteins to the site of damage and aid in their alignment and interaction with each other, thus enhancing the efficiency of the repair process.


Asunto(s)
Proteínas de Ciclo Celular , Reactivos de Enlaces Cruzados/metabolismo , Proteínas de Unión al ADN/metabolismo , Anemia de Fanconi/metabolismo , Ficusina/metabolismo , Proteínas Nucleares , Proteínas/metabolismo , Espectrina/metabolismo , Animales , Bovinos , Cromatina/metabolismo , Aductos de ADN/metabolismo , Daño del ADN , Reparación del ADN , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Proteína del Grupo de Complementación C de la Anemia de Fanconi , Proteína del Grupo de Complementación G de la Anemia de Fanconi , Proteínas del Grupo de Complementación de la Anemia de Fanconi , Células HeLa , Humanos , Pruebas de Precipitina , Unión Proteica , Espectrina/aislamiento & purificación
15.
Carcinogenesis ; 21(4): 741-51, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10753211

RESUMEN

The hypersensitivity of Fanconi anemia, complementation group A, (FA-A) cells to agents which produce DNA interstrand cross-links correlates with a defect in their ability to repair this type of damage. In order to more clearly elucidate this repair defect, chromatin-associated protein extracts from FA-A cells were examined for ability to endonucleolytically produce incisions in DNA at sites of interstrand cross-links. A defined 140 bp DNA substrate was constructed with a single site-specific monoadduct or interstrand cross-link produced by 4,5',8-trimethylpsoralen (TMP) plus long wavelength (UVA) light. Our results show that FA-A cells are defective in ability to produce dual incisions in DNA at sites of interstrand cross-links. Specifically, there is defective incision on the 3'- and 5'-sides of both the furan and pyrone sides of the cross-link. This defect is corrected in FA-A cells transduced with a retroviral vector expressing FANCA cDNA. At the site of a TMP monoadduct, FA-A cells can introduce incisions on both the 3'- and 5'-sides of the furan side monoadduct, but are defective in ability to produce these incisions on the pyrone side monoadduct. These studies also indicate that XPF is involved in production of the 5' incision by the normal extracts on these substrates. These results correlate with our previous work, which showed that FA-A cells are mainly defective in ability to repair psoralen interstrand cross-links with a lesser defect in ability to repair psoralen monoadducts. This defect in endonucleolytic incision at sites of TMP interstrand cross-links could be related to reduced levels of non-erythroid alpha spectrin (alphaSpIISigma*) in the extracts from FA-A cells. alphaSpIISigma* could act as a scaffold to align proteins involved in cross-link repair and enhance their interactions; a deficiency in alphaSpIISigma* could thus lead to reduced efficiency of repair and the decreased levels of incisions we observe at sites of interstrand cross-links in FA-A cells.


Asunto(s)
Reactivos de Enlaces Cruzados/metabolismo , Reparación del ADN , Anemia de Fanconi/genética , Trioxsaleno/análogos & derivados , Adenosina Trifosfato/farmacología , Secuencia de Bases , Línea Celular , ADN/metabolismo , Daño del ADN , Humanos , Datos de Secuencia Molecular , Trioxsaleno/metabolismo
17.
J Biol Chem ; 270(51): 30709-16, 1995 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-8530510

RESUMEN

Human chromatin-associated protein extracts were examined for endonucleolytic activity on a defined 132-base pair DNA substrate containing a single, site-specific 4,5'-8-trimethylpsoralen plus long wavelength ultraviolet light-induced furan side or pyrone side monoadduct or interstrand cross-link. These extracts produced incisions on both the 3' and 5' sides of each of these lesions. The distance between the 3' and 5' incisions at sites of a furan side monoadduct or cross-link was 9 nucleotides, and at sites of a pyrone side monoadduct or cross-link it was 17 nucleotides. Incisions on the 3' side of both types of furan side and pyrone side adducts were similar and were either at the fourth or fifth phosphodiester bond from the adducted thymine, depending upon the adduct. However, greater differences were observed between sites of 5' incision. This incision occurred at the fifth and sixth phosphodiester bonds from the adducted thymine at sites of furan side monoadducts and cross-links, respectively, and at the 13th and 14th phosphodiester bonds at sites of pyrone side monoadducts and cross-links, respectively. Thus, direct analysis of sites of endonucleolytic incision reveals that the location of sites of incision on TMP-adducted substrates depends upon the type of adduct present.


Asunto(s)
Cromatina/metabolismo , ADN/metabolismo , Endodesoxirribonucleasas/metabolismo , Oligodesoxirribonucleótidos/química , Oligodesoxirribonucleótidos/metabolismo , Trioxsaleno , Composición de Base , Secuencia de Bases , Sitios de Unión , Unión Competitiva , Línea Celular , Reactivos de Enlaces Cruzados , ADN/química , Furanos , Humanos , Cinética , Luz , Linfocitos , Modelos Estructurales , Datos de Secuencia Molecular , Proteínas Nucleares/metabolismo , Conformación de Ácido Nucleico , Oligodesoxirribonucleótidos/síntesis química , Pironas , Especificidad por Sustrato
18.
J Bacteriol ; 177(13): 3641-6, 1995 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-7601826

RESUMEN

Both the lethal and the mutagenic actions of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on cells of Streptococcus pneumoniae were greatly potentiated by a component of yeast extract added to the cellular environment. This component was found to be an oxidation product of glutathione, glutathione disulfide (GSSG). At low concentrations in the medium, both GSSG and glutathione potentiated MNNG action, but at high concentrations, glutathione (and other sulfhydryl compounds) abolished the effect. Point mutations in a cellular gene conferred resistance to the potentiating effect, and they blocked uptake of either GSSG or glutathione into the cells as well. This gene apparently encodes a component of the system for glutathione transport in S. pneumoniae. The mechanism by which GSSG, an apparently innocuous substance in the environment, renders low levels of MNNG genotoxic and cytotoxic thus depends on its transport into the cell, where it is reduced by glutathione reductase and then activates intracellular MNNG. Also, it was observed that mutants of S. pneumoniae defective in DNA mismatch repair are more resistant to MNNG than are wild-type cells by a factor of 2.5.


Asunto(s)
Glutatión/análogos & derivados , Metilnitronitrosoguanidina/farmacología , Mutagénesis , Mutágenos/farmacología , Streptococcus pneumoniae/efectos de los fármacos , Transporte Biológico , Proteínas Portadoras/metabolismo , Extractos Celulares/química , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Farmacorresistencia Microbiana , Genes Bacterianos , Glutatión/metabolismo , Glutatión/farmacología , Disulfuro de Glutatión , Metilnitronitrosoguanidina/toxicidad , Mutágenos/toxicidad , Oxidación-Reducción , Streptococcus pneumoniae/genética , Levaduras/química
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