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1.
Comput Biol Med ; 152: 106372, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36516574

RESUMO

Uncontrolled proliferation of B-lymphoblast cells is a common characterization of Acute Lymphoblastic Leukemia (ALL). B-lymphoblasts are found in large numbers in peripheral blood in malignant cases. Early detection of the cell in bone marrow is essential as the disease progresses rapidly if left untreated. However, automated classification of the cell is challenging, owing to its fine-grained variability with B-lymphoid precursor cells and imbalanced data points. Deep learning algorithms demonstrate potential for such fine-grained classification as well as suffer from the imbalanced class problem. In this paper, we explore different deep learning-based State-Of-The-Art (SOTA) approaches to tackle imbalanced classification problems. Our experiment includes input, GAN (Generative Adversarial Networks), and loss-based methods to mitigate the issue of imbalanced class on the challenging C-NMC and ALLIDB-2 dataset for leukemia detection. We have shown empirical evidence that loss-based methods outperform GAN-based and input-based methods in imbalanced classification scenarios.


Assuntos
Algoritmos , Leucemia-Linfoma Linfoblástico de Células Precursoras , Humanos , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia
2.
Int J Pharm ; 629: 122358, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36332832

RESUMO

This work highlights boosting the tumor targeting efficiency of epirubicin through loading on a new radionanosystem, based on the effective role of silver nanoparticles (AgNPs). Accordingly, PEGylated silver nanoparticles (PEG/AgNPs) were prepared in a size of 20.2 ± 0.1 nm. Additionally, epirubicin was loaded on PEG/AgNPs with a loading efficiency of 63 ± 3 %. Furthermore, both of PEG/AgNPs and EPI/PEG/AgNPs were radiolabeled with 131I isotope with radiolabeling yields of 85 ± 0.2 % and 90.3 ± 1 %, respectively. The in-vivo distribution of 131I-PEG/AgNPs and 131I-EPI/PEG/AgNPs were examined in healthy and tumor bearing mice models. Excitingly, 131I-EPI/PEG/AgNPs revealed a reticuloendothelial system (RES) avoidance and prolonged circulating time. In addition, 131I-EPI/PEG/AgNPs showed fast targeting of tumor site by 25.1 ± 0.1 %ID/g within 0.5 h after intravenous injection. Subsequently, the outcomes provided 131I-EPI/PEG/AgNPs as a new potential system for enhancement of tumor targeting and theranosis (therapy and/or imaging).


Assuntos
Nanopartículas Metálicas , Nanopartículas , Neoplasias , Camundongos , Animais , Epirubicina , Prata , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Polietilenoglicóis
3.
Comput Biol Med ; 139: 104931, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34666229

RESUMO

Invasive ductal carcinoma (IDC) breast cancer is a significant health concern for women all around the world and early detection of the disease may increase the survival rate in patients. Therefore, Computer-Aided Diagnosis (CAD) based systems can assist pathologists to detect the disease early. In this study, we present an ensemble model to detect IDC using DenseNet-121 and DenseNet-169 followed by test time augmentation (TTA). The model achieved a balanced accuracy of 92.70% and an F1-score of 95.70% outperforming the current state-of-the-art. Comparative analysis against various pre-trained deep learning models and preprocessing methods have been carried out. Qualitative analysis has also been conducted on the test dataset. After the detection of IDC breast cancer, it is important to grade it for further treatment. In our study, we also propose an ensemble model for the grading of IDC using the pre-trained DenseNet-121, DenseNet-201, ResNet-101v2, and ResNet-50 architectures. The model is inferred from two validation cohorts. For the patch-level classification, the model yielded an overall accuracy of 69.31%, 75.07%, 61.85%, and 60.50% on one validation cohort and 62.44%, 79.14%, 76.62%, and 71.05% on the second validation cohort for 4×, 10×, 20×, and 40× magnified images respectively. The same architecture is further validated using a different IDC dataset where it achieved an overall accuracy of 90.07%. The performance of the models on the detection and grading of IDC shows that they can be useful to help pathologists detect and grade the disease.


Assuntos
Neoplasias da Mama , Carcinoma Ductal de Mama , Carcinoma Ductal , Aprendizado Profundo , Neoplasias da Mama/diagnóstico por imagem , Carcinoma Ductal de Mama/diagnóstico por imagem , Diagnóstico por Computador , Feminino , Humanos , Taxa de Sobrevida
4.
Langmuir ; 36(16): 4261-4271, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32243167

RESUMO

The self-assembly and the dynamics of an H-shaped copolymer composed of a polyethylene midblock and four poly(ethylene oxide) arms (PE-b-4PEO) are investigated in the bulk and under severe confinement into nanometer-spaced LAPONITE clay particles by means of small- and wide-angle X-ray diffraction (SAXS, WAXS), differential scanning calorimetry (DSC), polarizing optical microscopy (POM), rheology, and dielectric spectroscopy (DS). Because of the H-shaped architecture, the PE midblock is topologically frustrated and thus unable to crystallize. The superstructure formation in the bulk is dictated solely by the PEO arms as inferred by the crystallization/melting temperature relative to the PEO homopolymer. Confinement produced remarkable changes in the interlayer distance and PEO crystallinity but left the local segmental dynamics unaltered. To reconcile all structural, thermodynamic, and dynamic effects, a novel morphological picture is proposed with interest in emulsions. Key parameters that stabilize the final morphology are the severe chain confinement with the associated entropy loss and the presence of interactions (hydrophobic/hydrophilic) between the LAPONITE and the PEO/PE blocks.

5.
Artigo em Inglês | MEDLINE | ID: mdl-28256028

RESUMO

BACKGROUND: Development of pharyngo-esophageal protective reflexes among infants with hypoxic ischemic encephalopathy (HIE) is unclear. Our aim was to distinguish these reflexes from controls and examine the maturational changes in HIE infants. METHODS: We evaluated 14 HIE infants (seven males) at 41.4±0.6 (HIE Time-1) and 46.5±0.6 (HIE Time-2) weeks postmenstrual age (PMA). Seven controls (three males) were evaluated at 43.5±1.3 weeks PMA. Graded pharyngeal stimulation with liquids (0.1, 0.3, 0.5 mL in triplicate) concurrent with high-resolution manometry was used to analyze sensory-motor components of pharyngeal reflexive swallowing (PRS), upper esophageal sphincter (UES), contractile reflex (PUCR), and esophageal body characteristics. Linear mixed and generalized estimating equation models were used for comparison among groups. KEY RESULTS: Compared to controls, HIE infants (Time-1 and Time-2) exhibited decreased number of pharyngeal peaks and latency to terminal swallow. HIE Time-1 infants showed increased UES resting tone and distal latency, compared to controls and HIE Time-2. Contractile vigor was increasingly abnormal during maturation, compared to healthy controls. Threshold volumes and frequency distribution of primary responses (PRS: PUCR: None) were not significant among all groups. CONCLUSIONS & INFERENCES: Compared to controls, HIE infants display significant hypertonicity of skeletal muscle components, impairment of pharyngeal provocation-induced reflexes and smooth muscle contractile vigor, reflecting poor propagation with maturation. These mechanisms may be responsible for inadequate clearance of secretions, ascending refluxate, and oropharyngeal bolus in HIE infants.


Assuntos
Asfixia Neonatal/fisiopatologia , Desenvolvimento Infantil/fisiologia , Engasgo/fisiologia , Contração Muscular/fisiologia , Asfixia Neonatal/diagnóstico , Feminino , Humanos , Recém-Nascido , Masculino , Manometria/métodos
6.
Ann Trop Med Parasitol ; 105(3): 241-50, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21801503

RESUMO

Although intestinal parasitic infections (IPI) among children remain a global issue, the current information on such infections in Albanian children is very limited. A cross-sectional study of the IPI in 321 children living in the Albanian counties of Tirana (152) and Elbasan (169) was therefore conducted in 2008, with a pre-tested standard questionnaire employed to gather the relevant personal and clinical data. Using formalin-ether concentration and permanent stains, stool samples were examined microscopically for the ova, cysts and oocysts of any parasites. The overall prevalence of IPI was 19% (61 of 321), with protozoan infections (11·5%) apparently more common than infections with soil-transmitted helminths (STH; 8·1%). Giardia duodenalis was the parasite most frequently detected (10·9%), followed by hookworm (5·6%), Ascaris lumbricoides (1·9%), Trichuris trichiura (0·6%), Cryptosporidium (0·3%) and Entamoeba histolytica/dispar (0·3%). The results of a univariate analysis indicated that the children from Tirana county were significantly more likely to be found infected with STH compared with the children from Elbasan county (12·5% v. 4·1%; P=0·006). Children sampled in the community were also more likely to be found STH-positive than the children sampled as they attended hospitals and health clinics (10·5% v. 6·0%) but this difference did not reach statistical significance. The children found STH-positive were five times more likely to be suffering from diarrhoea than the other children checked in clinical settings (P=0·004) and were also more likely to be suffering from abdominal pain (P=0·054) and/or diminished appetite (P=0·016).


Assuntos
Enteropatias Parasitárias/epidemiologia , Dor Abdominal/epidemiologia , Dor Abdominal/parasitologia , Adolescente , Albânia/epidemiologia , Criança , Pré-Escolar , Diarreia/epidemiologia , Diarreia/parasitologia , Métodos Epidemiológicos , Fezes/parasitologia , Transtornos da Alimentação e da Ingestão de Alimentos/epidemiologia , Transtornos da Alimentação e da Ingestão de Alimentos/parasitologia , Feminino , Helmintíase/complicações , Helmintíase/epidemiologia , Helmintíase/transmissão , Humanos , Lactente , Enteropatias Parasitárias/complicações , Masculino , Infecções por Protozoários/epidemiologia , Solo/parasitologia
7.
Oncogene ; 26(29): 4199-208, 2007 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-17224908

RESUMO

The ubiquitin (Ub)-proteasome system (UPS) promotes the proteasomal degradation of target proteins by decorating them with Ub labels. Emerging evidence indicates a role of UPS in regulating gene transcription. In this study, we provided evidence for the involvement of UPS in the transcriptional activation function of tumor suppressor p53. We showed that both ubiquitylation and proteasomal functions are required for efficient transcription mediated by p53. Disruption of transcription by actinomycin D, 5,6-dichloro-1-beta-D-ribofuranosyl-benzimadazole or alpha-amanitin leads to accumulation of cellular p53 protein. Proteasome inhibition by MG132 increases the occupancy of p53 protein at p53-responsive p21(waf1) promoter. In addition, the Sug-1 component of 19S proteasome physically interacts with p53 in vitro and in vivo. Moreover, in response to ultraviolet-induced DNA damage, both the 19S proteasomal components, Sug1 and S1, are recruited to p21(waf1) promoter region in a kinetic pattern similar to that of p53. These results suggested that UPS positively regulates p53-mediated transcription at p21(waf1) promoter.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Regiões Promotoras Genéticas , Complexo de Endopeptidases do Proteassoma/fisiologia , Ativação Transcricional/genética , Proteína Supressora de Tumor p53/fisiologia , Enzimas Ativadoras de Ubiquitina/fisiologia , Animais , Linhagem Celular Tumoral , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/biossíntese , Células HeLa , Humanos , Síndrome de Li-Fraumeni/genética , Síndrome de Li-Fraumeni/metabolismo , Síndrome de Li-Fraumeni/patologia , Camundongos
9.
Pharmacol Res ; 48(5): 461-5, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12967591

RESUMO

The therapeutic value of doxorubicin (DOX) as anticancer antibiotic is limited by its cardiotoxicity. The implication of natural phenolic acids in the prevention of many pathologic diseases has been reported. Herein, the ability of p-coumaric (PC) acid, a member of phenolic acids, to protect rat's heart against DOX-induced oxidative stress was investigated. Three main groups of albino rats were used; DOX, PC, and PC plus DOX-receiving animals. Corresponding control animals were also used. DOX was administered i.p. in a single dose of 15mgkg(-1). PC alone, in a dose of 100mgkg(-1), was orally administered for five consecutive days. In PC/DOX group, rats received PC 5 days prior to DOX. DOX-induced high serum levels of lactic dehydrogenase (LDH) and creatine phosphokinase (CPK), were reduced significantly by PC administration, compared to DOX-receiving rats. Pretreatment with PC ameliorated the cardiac content of glutathione (GSH), and superoxide dismutase (SOD) & catalase (CAT) activities, compared to DOX-receiving rats. On the other hand, accumulation of cardiac content of MDA significantly decreased following PC pretreatment, compared to DOX-treated rats. The data presented here indicate that PC protects rats hearts against DOX-induced oxidative stress in the heart. It may be worthy to consider the usefulness of PC as adjuvant therapy in cancer management.


Assuntos
Antibacterianos/farmacologia , Ácidos Cumáricos/farmacologia , Doxorrubicina/farmacologia , Coração/efeitos dos fármacos , Miocárdio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Creatina Quinase/metabolismo , Glutationa/metabolismo , L-Lactato Desidrogenase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Oxirredução , Propionatos , Proteínas/metabolismo , Ratos , Superóxido Dismutase/metabolismo
10.
Mol Carcinog ; 28(4): 215-24, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10972991

RESUMO

The increase in the p53 activity in response to DNA damage is thought to be one of the important mechanisms by which p53 contributes to transcriptional activation of p21(wafl), mdm2, and other downstream regulatory genes. To investigate the p53 response to ultraviolet (UV) type of DNA damage, p53 protein level, its transcriptional activity and in vivo ubiquitination were compared in repair-proficient normal human fibroblasts (NHFs) and repair-deficient xeroderma pigmentosum (XP) group A and group C (XP-C) fibroblasts subsequent to irradiation with UV light. Accumulation of p53 protein level was observed with increasing UV doses in all the cell lines; however, discordance between p53 and p21(waf1) and mdm2 levels was observed in NHF and XP-A cells. Induction of p21(waf1) and mdm2 was inhibited by UV irradiation, requiring higher doses in NHF and lower doses in XP-A cells. However, inhibition of p21(waf1) and mdm2 induction was not observed in XP-C cells. Ubiquitin-p53 conjugates could be detected in irradiated or unirradiated NHF and XP-A cells but not in XP-C cells irradiated with 30 and 50 J/m(2) UV light. Using a p53 reporter assay, p53 transcriptional activities were found to be induced by 10 J/m(2) UV exposure and dramatically inhibited with increasing UV doses in NHF cells. Compared with repair-proficient NHF cells, UV inhibition of p53 transcriptional activity was relatively more sensitive in XP-A cells but resistant in XP-C cells. These results indicate that DNA damage by UV, in addition to inducing p53, acts as a trigger for inhibition of p53 transcriptional activity. Overall, recognition of DNA damage links both p53 induction and p53 degradation to DNA repair mechanisms.


Assuntos
Dano ao DNA , Reparo do DNA , Genes p53/efeitos da radiação , Transcrição Gênica/efeitos da radiação , Proteína Supressora de Tumor p53/metabolismo , Raios Ultravioleta , Linhagem Celular , Fibroblastos , Genes Reporter , Humanos , Luciferases/genética , Transfecção , Proteína Supressora de Tumor p53/genética , Ubiquitinas/metabolismo , Xeroderma Pigmentoso/genética
11.
Cancer Res ; 60(8): 2273-80, 2000 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-10786695

RESUMO

DNA damage from exposure to environmental chemical carcinogens and failure of repair systems to eliminate these lesions from the genome are considered as the crucial initial steps in the development of various human malignancies. Many cellular proteins are known to play vital roles to overcome the effects of DNA damage. Among such proteins, p53 is known to respond to DNA damage by accumulating in the nucleus and inhibiting cell cycle progression to facilitate DNA repair and the maintenance of genomic stability. In this study, we have investigated the role of p53 protein in modulating nucleotide excision repair of anti-benzo-(a)pyrene-diol-epoxide (BPDE)-DNA adducts and related effects using human fibroblasts with normal (p53-WT) and altered p53 protein (p53Mut and p53-Null). Interestingly, irrespective of the presence or absence of p53, the anti-BPDE dose-dependent p21 protein induction response was qualitatively comparable in all of the three cell lines. However, cells with defective p53 function were deficient for the removal of anti-BPDE-DNA adducts from the overall genome compared to cells with wild-type p53 activity. Strand-specific repair analysis within the individual strands of the p53 gene revealed decreased repair of adducts from the nontranscribed strand in p53-Mut and p53-Null cells. However, the repair of the transcribed strand appeared to be identical in all of the three cell lines. Furthermore, p53-Mut and p53-Null cells were more sensitive than p53-WT cells and displayed increased levels of anti-BPDE-induced apoptosis. Thus, wild-type p53 is required for the efficient global genomic repair of anti-BPDE-induced DNA adducts from the overall genome, but not for transcription-coupled repair of actively transcribed genes. These findings indicate that inefficient DNA repair of potentially cytotoxic and mutagenic lesions from the nontranscribed strand due to the loss of p53, but not the loss of p21, function might be responsible for enhanced cytotoxicity and apoptosis in human cells upon DNA damage.


Assuntos
Benzopirenos/toxicidade , Carcinógenos/toxicidade , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Genoma Humano , Proteína Supressora de Tumor p53/metabolismo , 7,8-Di-Hidro-7,8-Di-Hidroxibenzo(a)pireno 9,10-óxido/metabolismo , Apoptose/efeitos dos fármacos , Benzopirenos/metabolismo , Carcinógenos/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/metabolismo , Adutos de DNA/metabolismo , Dano ao DNA/genética , Reparo do DNA/genética , DNA de Cadeia Simples/efeitos dos fármacos , DNA de Cadeia Simples/genética , Relação Dose-Resposta a Droga , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Genes p53/genética , Humanos , Mutação/genética , Transcrição Gênica/efeitos dos fármacos , Transcrição Gênica/genética , Proteína Supressora de Tumor p53/genética , Regulação para Cima/efeitos dos fármacos
12.
Mutat Res ; 459(2): 135-45, 2000 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-10725664

RESUMO

Nucleotide excision repair (NER), the most versatile and ubiquitous mechanism for DNA repair, operates to remove many types of DNA base lesions. We have studied the role of p53 function in modulating the repair of DNA damage following UV irradiation in normal and p53-compromised human mammary epithelial cells (HMEC). The effect of UV-induced DNA damage on cellular cytotoxicity and apoptosis was determined in conjunction with global, gene- and strand-specific repair. Cytotoxicity studies, using clonogenic survival and MTT assays, showed that HPV-16 E6-expressing HMEC were more UV sensitive than p53-WT cell lines. High apoptotic index obtained with p53-compromised cells was in conformity to both the low clonogenic survival and the low cellular viability. No discernible differences in the formation of initial UV-induced cyclobutane pyrimidine dimers (CPD) were observed in the cell lines of varying p53 functional status. However, the extent and the rate of damage removal from genome overall were highest for p53-WT cells. Further examination of strand-specific repair in the p53 gene revealed that the removal of CPD in the non-transcribed strand (NTS) was slower in p53-compromised cells compared to the normal p53-WT cell lines. These results suggest that loss of p53 function, in the absence of other genetic alterations, decreased both overall amount of CPD repaired and their removal rate from the genome. Additionally, normal function of p53 is required for the repair of the NTS, but not of the transcribed strand (TS) in genomic DNA in human epithelial cells. Thus, failure of quantitative removal of CPD by global genomic repair (GGR), due to loss of p53 function, causes the enhanced UV sensitivity and increased damage-induced apoptosis via a p53-independent pathway. Nevertheless, recovery of cells from UV damage requires normal p53 function and efficient GGR.


Assuntos
Reparo do DNA , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae/metabolismo , Dímeros de Pirimidina/metabolismo , Proteínas Repressoras , Proteína Supressora de Tumor p53/metabolismo , Apoptose/efeitos da radiação , Mama/citologia , Mama/efeitos da radiação , Células Cultivadas , Células Epiteliais/citologia , Humanos , Transcrição Gênica , Raios Ultravioleta
13.
East Mediterr Health J ; 6(5-6): 979-86, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-12197357

RESUMO

We investigated the effects of vinyl chloride monomer exposure on the liver of 86 workers by measuring beta-glucuronidase, arylsulfatase A, adenosine deaminase, 5'-nucleotidase and routine liver function enzymes in the sera of the workers. In 21 of them, three or more of these parameters were raised, with a significant decrease in the level of blood glutathione and a significant increase in the enzyme activity level of glutathione S-transferase. Of these 21 workers, 14 had fatty liver infiltration, 8 of whom were also suffering from liver enlargement. Also, 4 workers had liver enlargement without fatty infiltration and 3 had enlarged spleens. The study highlights the need for vigilance in environmental monitoring and medical surveillance of workers exposed to this chemical.


Assuntos
Carcinógenos , Fígado Gorduroso/induzido quimicamente , Hepatomegalia/induzido quimicamente , Doenças Profissionais/induzido quimicamente , Exposição Ocupacional/efeitos adversos , Esplenomegalia/induzido quimicamente , Cloreto de Vinil/intoxicação , 5'-Nucleotidase/sangue , Adenosina Desaminase/sangue , Adulto , Estudos de Casos e Controles , Cerebrosídeo Sulfatase/sangue , Egito , Monitoramento Ambiental , Fígado Gorduroso/diagnóstico , Fígado Gorduroso/enzimologia , Fígado Gorduroso/prevenção & controle , Glucuronidase/sangue , Glutationa Transferase/sangue , Hepatomegalia/diagnóstico , Hepatomegalia/enzimologia , Hepatomegalia/prevenção & controle , Humanos , Testes de Função Hepática , Masculino , Avaliação das Necessidades , Doenças Profissionais/diagnóstico , Doenças Profissionais/enzimologia , Doenças Profissionais/prevenção & controle , Exposição Ocupacional/análise , Saúde Ocupacional , Esplenomegalia/diagnóstico , Esplenomegalia/enzimologia , Esplenomegalia/prevenção & controle
14.
J Biol Chem ; 275(15): 11492-7, 2000 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-10753968

RESUMO

The tumor suppressor protein p53 plays a central role in modulating the cellular responses to DNA damage. Several recent studies, undertaken with the whole genomic DNA or full-length gene segments, have shown that p53 is involved in nucleotide excision repair and it selectively influences the adduct removal from the non-transcribed strand in the genome. In this study, we have analyzed the damage induction at nucleotide resolution by ligase-mediated polymerase chain reaction and compared the repair of ultraviolet radiation-induced cyclobutane pyrimidine dimers within exon 8 of p53 gene in normal and Li-Fraumeni syndrome fibroblasts as well as in normal and human papillomavirus 16 E6 and E7 protein-expressing human mammary epithelial cells. The results demonstrate that (i) loss or disruption of p53 function decreases efficiency of DNA repair, by preferentially affecting the repair of non-transcribed strand and of intrinsically slow repair sites in transcribed strand; (ii) mutant p53 protein affects DNA repair, at least of non-transcribed strand, in a dominant negative manner; and (iii) pRb does not have an effect on the repair of DNA damage within transcribed or non-transcribed strand. The overall data suggest that p53 could regulate excision repair or related events through direct protein-protein interaction.


Assuntos
Reparo do DNA , Proteína Supressora de Tumor p53/fisiologia , Células Cultivadas , Humanos , Dímeros de Pirimidina/metabolismo , Transcrição Gênica
15.
Carcinogenesis ; 20(5): 765-72, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10334192

RESUMO

A network of interacting cellular components is known to mediate the regulatory role of tumor suppressor protein p53 in genomic stability. DNA repair machinery is considered to be one of these vital cellular components. To investigate the modulatory function of p53 on the repair of DNA damage and related effects, we have studied the responses of human p53-wild-type (p53-WT), p53-mutant (p53-Mut) and p53-nullizygous (p53-Null) cells following exposure to UV irradiation. Absence of wild-type p53 function coincided with an enhanced sensitivity to UV, as well as induction of apoptosis. However, the lack of wild-type p53 expression did not affect the response of its signal transducer protein, p21. Repair analysis of specific genomic sequences, at a single nucleotide resolution, revealed that the removal of cyclobutane pyrimidine dimers in a non-transcribed strand was significantly slower in p53-Mut and p53-Null cell lines compared with the normal p53-WT cells. However, the repair of the transcribed strand was comparable in the three cell lines. Thus, p53 is required for the efficient nucleotide excision repair (NER) of the global genomic DNA, but not for the transcription-coupled repair of the essential genes. The decreased global NER, due to the lost p53 function, seems to be responsible for the conjoined cytotoxicity and apoptosis of human cells subjected to DNA stress damage.


Assuntos
Apoptose/fisiologia , Reparo do DNA/fisiologia , Proteína Supressora de Tumor p53/fisiologia , Apoptose/efeitos da radiação , Linhagem Celular , Fragmentação do DNA/efeitos da radiação , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Genes Supressores de Tumor/fisiologia , Humanos , Mutação , Células Tumorais Cultivadas/citologia , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/efeitos da radiação , Proteína Supressora de Tumor p53/genética , Raios Ultravioleta
16.
Rev Neurol (Paris) ; 147(2): 111-20, 1991.
Artigo em Francês | MEDLINE | ID: mdl-2028145

RESUMO

Between 1972 and 1989, 131 unruptured intracranial saccular aneurysms were clipped in the Neurosurgical Department of La Pitié Hospital, Paris. Only 89 of these are considered here, the remaining 42 aneurysms having been discovered and clipped during surgery for a ruptured aneurysm. All isolated unruptured aneurysms were detected by angiography, computerized tomography or magnetic resonance imaging. Twenty out of the 89 aneurysms were asymptomatic ("incidental") while 69 were accompanied by clinical symptoms indicating radiological examination. It is generally accepted that in ruptured aneurysms the mortality rate during 3 days following the rupture is about 50 percent, and for this reason many neurosurgeons are in favour of unruptured aneurysms being treated either by open surgery with clipping of the aneurysmal neck or by inserting a balloon into the aneurysmal sac. The results obtained in 377 published cases, including ours, justify this approach: no recurrent bleeding was observed after open surgery and the mortality rate was nil when the contra-indications of surgery were respected. There was a permanent morbidity of less than 2 per cent directly related to the surgeon's experience.


Assuntos
Aneurisma Intracraniano/cirurgia , Adulto , Ética Médica , Feminino , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/patologia , Masculino , Radiografia , Ruptura Espontânea
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