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1.
Sensors (Basel) ; 21(4)2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33669506

RESUMO

Deep learning is the mainstream paradigm in computer vision and machine learning, but performance is usually not as good as expected when used for applications in robot vision. The problem is that robot sensing is inherently active, and often, relevant data is scarce for many application domains. This calls for novel deep learning approaches that can offer a good performance at a lower data consumption cost. We address here monocular depth estimation in warehouse automation with new methods and three different deep architectures. Our results suggest that the incorporation of sensor models and prior knowledge relative to robotic active vision, can consistently improve the results and learning performance from fewer than usual training samples, as compared to standard data-driven deep learning.

2.
J Assist Reprod Genet ; 34(5): 617-625, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28281144

RESUMO

PURPOSE: We evaluated the relationship between meiotic spindle characteristics and in vitro fertilization cycle outcome. METHODS: Five hundred sixty-nine oocytes from 86 in vitro fertilization cycles were analyzed for fertilization and subsequent implantation rates. Oocytes were assessed for maturation status. The oocytes and embryos were cultured in sequential and nonsequential media (G Series, Vitrolife, Sweden) and incubated in 6% CO2, 5% O2 at 37 °C. Two hours following oocyte decumulation (38-39 h post-hCG/GnRH administration) and prior to microinjection, the structure of the meiotic spindle was assessed using the Oosight Imaging System (CRI, UK). RESULTS: Four hundred fifty-six oocytes (80.5%) had a visible meiotic spindle, 82 (14.7%) had no meiotic spindle, and 31 (5.5%) were in telophase I. Oocytes exhibiting a meiotic spindle had a significantly higher fertilization rate and a lower rate of abnormal fertilization. Implantation data were obtained for 195 of the embryos transferred. The implantation rate for embryos derived from oocytes with a meiotic spindle was 32.9%, while in embryos originating from oocytes without a meiotic spindle and oocytes in telophase, this value dropped significantly (8.8 and 0%, respectively). To determine the correlation between retardance values and implantation rate for each oocyte, we established four groups, finding a range of retardance values with significantly higher implantation rates (27.5, 21, 29.3, and 53.8%, respectively). CONCLUSION: Meiotic spindle imaging may be a valuable tool for prediction of oocyte quality, and retardance values of meiotic spindles, together with classical morphological classification, can be useful to select embryos with a higher implantation potential.


Assuntos
Desenvolvimento Embrionário , Fertilização in vitro , Oócitos/ultraestrutura , Fuso Acromático/ultraestrutura , Gonadotropina Coriônica/administração & dosagem , Implantação do Embrião/efeitos dos fármacos , Feminino , Hormônio Liberador de Gonadotropina/administração & dosagem , Humanos , Masculino , Microscopia de Polarização , Oócitos/efeitos dos fármacos , Gravidez , Injeções de Esperma Intracitoplásmicas , Fuso Acromático/efeitos dos fármacos , Suécia
3.
J Anim Ecol ; 82(5): 1106-15, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23550633

RESUMO

1. Chiropterophilic flowers secrete sugar nectar with low-Nitrogen (N hereafter) content and small amounts of amino acids, which may function to attract animals; nevertheless, the role that micronutrients have on the foraging decisions of Neotropical nectarivorous bats is unknown. 2. We offered the nectar specialist Leptonycteris yerbabueanae and the omnivore Glossophaga soricina pairs of experimental diets mimicking either the N content or the relative abundance of 17 amino acids found in the floral nectar from the main plant species visited by these bats in a tropical dry forest. We addressed the following research questions: (i) Do bats select N-containing or sugar-only nectar differently based on bats' N nutritional status? (ii) Does the presence of N in nectar affect the capacity of bats to discriminate and select other nectar traits such as sugar concentration? and (iii) Are bats able to distinguish among the flavours generated by the amino acid relative abundance present in the nectar from plants they typically encounter in nature? 3. Our results showed that: (i) bats did not consider nectar N content regardless of their N nutritional condition, (ii) the nectar specialist L. yerbabuenae showed a preference for the most concentrated sugar-only nectar but changed to be indifferent when nectar contained N, and (iii) L. yerbabuenae preferred diets without amino acids and preferred the taste of the amino acids present in the nectar of Pachycereus pecten (Cactaceae) over those present in the nectar of Ceiba aesculifolia (Bombacaceae). 4. Our results suggest that regardless of the low concentrations at which N and amino acids are present in floral nectar, their presence affects bats' food selection by interfering with the bats' ability to detect differences in sugar concentrations, and by offering particular flavours that can be perceived and selected by nectarivorous bats. We discuss the ecological implications of the presence of N and amino acids in nectar on bats' foraging decisions.


Assuntos
Aminoácidos/metabolismo , Quirópteros/fisiologia , Preferências Alimentares/fisiologia , Nitrogênio/metabolismo , Néctar de Plantas/química , Aminoácidos/análise , Animais , Cactaceae/química , Carboidratos/análise , Ceiba/química , Dieta , Masculino , Desnutrição , México , Nitrogênio/análise
4.
Ecancermedicalscience ; 17: 1620, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38414942

RESUMO

Given the lack of publications and public policies addressing the relationship between climate change and cancer care in Colombia, we present an exploration of the perspectives and communication practices of a group of nurses from Valle del Cauca and Antioquia. We provide a context based on the available literature on climate change and general health then provide an overview of cancer in the country. Next, we present how oncology nurses have incorporated information about strategies their patients can use to mitigate the effects of climate change on their health. We highlight the centrality of patient-centered communication using a framework from the US National Cancer Institute) and the fundamental role nurses have in patients' experiences throughout their treatment. We conclude with the need to investigate oncology nurse communication practices in other Colombian hospitals, with consideration of culture, cancer stigma, barriers to care and other factors that may influence successful climate change mitigation and to better understand how other Latin American oncology nurses are addressing this serious challenge.

5.
J Biol Chem ; 286(5): 3484-96, 2011 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-21115488

RESUMO

Three specific ß(1,3)glucan synthase (GS) inhibitor families, papulacandins, acidic terpenoids, and echinocandins, have been analyzed in Schizosaccharomyces pombe wild-type and papulacandin-resistant cells and GS activities. Papulacandin and enfumafungin produced similar in vivo effects, different from that of echinocandins. Also, papulacandin was the strongest in vitro GS inhibitor (IC(50) 10(3)-10(4)-fold lower than with enfumafungin or pneumocandin), but caspofungin was by far the most efficient antifungal because of the following. 1) It was the only drug that affected resistant cells (minimal inhibitory concentration close to that of the wild type). 2) It was a strong inhibitor of wild-type GS (IC(50) close to that of papulacandin). 3) It was the best inhibitor of mutant GS. Moreover, caspofungin showed a special effect for two GS inhibition activities, of high and low affinity, separated by 2 log orders, with no increase in inhibition. pbr1-8 and pbr1-6 resistances are due to single substitutions in the essential Bgs4 GS, located close to the resistance hot spot 1 region described in Saccharomyces and Candida Fks mutants. Bgs4(pbr)(1-8) contains the E700V change, four residues N-terminal from hot spot 1 defining a larger resistance hot spot 1-1 of 13 amino acids. Bgs4(pbr)(1-6) contains the W760S substitution, defining a new resistance hot spot 1-2. We observed spontaneous revertants of the spherical pbr1-6 phenotype and found that an additional A914V change is involved in the recovery of the wild-type cell shape, but it maintains the resistance phenotype. A better understanding of the mechanism of action of the antifungals available should help to improve their activity and to identify new antifungal targets.


Assuntos
Antifúngicos/farmacologia , Farmacorresistência Fúngica/genética , Inibidores Enzimáticos/farmacologia , Glucosiltransferases/antagonistas & inibidores , Proteínas de Schizosaccharomyces pombe/antagonistas & inibidores , Aminoglicosídeos/farmacologia , Equinocandinas/farmacologia , Concentração Inibidora 50 , Mutação de Sentido Incorreto , Schizosaccharomyces/enzimologia , Terpenos/farmacologia
6.
Appl Radiat Isot ; 167: 109450, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33086152

RESUMO

The shielding features of amethyst, chalcedony, crystal rock, milky, pink, flint, and jasper quartz were calculated. The seven varieties of quartz were collected within the territory of the state of Zacatecas in Mexico. Shielding characteristics include the linear attenuation coefficients, the effective atomic numbers and the mass interaction coefficients for 1 keV to 100 GeV photons. The interaction coefficients were calculated for the coherent scattering, the photoelectric absorption, the Compton scattering, and the pair production occurring in the electric field of the atomic nucleus and the electrons. The linear attenuation coefficients were compared with those of the Portland concrete widely used as radiation shielding. In the low energy region where the photoelectric absorption is dominant the mass interaction coefficients and the total linear attenuation coefficients have three resonances due to the Si, Ca and Fe concentration, these resonances are also noticed in the effective atomic number. For photons below 60 keV the shielding performance of quartz can be used to shield X-ray devices working with less than 60 kV.

7.
Eukaryot Cell ; 8(9): 1449-59, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19633265

RESUMO

In Saccharomyces cerevisiae, the simultaneous absence of Slt2 and Rim101 prevents growth in nonosmotically stabilized media (F. Castrejon et al., Eukaryot. Cell 5:507-517, 2006). The double mutant slt2Delta rim101Delta displays altered chitin rings, together with a significant reduction in the overall levels of chitin. Cultures of this mutant lyse upon transfer to nonosmotically stabilized media, mostly through the bud, and such lysis is partially prevented by deletion of the chitinase gene (CTS1). Growth of the slt2Delta rim101Delta double mutant was restored by the overexpression of the GFA1 or CCT7 genes, which code for two biologically unrelated proteins. Further characterization of the mutant and its suppressors indicated that both Slt2 and Rim101 were independently required for the correct assembly of the septum machinery and that their concomitant absence reduced Chs3 accumulation at the neck, leading to lower levels of chitin. GFA1 overexpression, as well as the addition of glucosamine to the growth medium, specifically suppressed the growth defects by activating chitin synthesis at the neck and restoring the normal assembly of the chitin ring. In contrast, overexpression of CCT7, a Cct chaperonin subunit, alleviated the defect in the septum machinery without affecting chitin synthesis. Both suppressors thus act by reducing neck fragility through different mechanisms and allow growth in nonstabilized media. This work reports new roles for Slt2 and Rim101 in septum formation in budding yeast and confirms the homeostatic role of the chitin ring in the maintenance of neck integrity during cell division.


Assuntos
Divisão Celular , Quitina/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Repressoras/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Quitina/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Repressoras/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
8.
Appl Radiat Isot ; 161: 109129, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32250840

RESUMO

Responses of a novel passive neutron area monitor, named CubBonner, were calculated. The responses were estimated for sixty monoenergetic neutrons, from 10-9 to 20 MeV, with the MCNP5 code. The CubBonner is a cubic polyethylene moderator and a gold foil as thermal neutron detector. The ambient dose equivalent response was calculated for three cubes (5″, 8″ and 10" side) with the gold foil at the cube's centers. The moderator cube having the best ambient dose equivalent response was used to estimate the neutron fluence and the 197Au(n,γ) responses per history. The ambient dose response per unit mass of gold was compared with the response of the Berthold LB 6411 active neutron area monitor, and the response for the (n,γ) reaction in the gold foil was compared with the evaporation photo neutrons produced in linear accelerators for radiotherapy.

9.
J Chem Inf Model ; 49(9): 2129-38, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19728739

RESUMO

The information provided by the alignment-independent GRid Independent Descriptors (GRIND) can be condensed by the application of principal component analysis, obtaining a small number of principal properties (GRIND-PP), which is more suitable for describing molecular similarity. The objective of the present study is to optimize diverse parameters involved in the obtention of the GRIND-PP and validate their suitability for applications, requiring a biologically relevant description of the molecular similarity. With this aim, GRIND-PP computed with a collection of diverse settings were used to carry out ligand-based virtual screening (LBVS) on standard conditions. The quality of the results obtained was remarkable and comparable with other LBVS methods, and their detailed statistical analysis allowed to identify the method settings more determinant for the quality of the results and their optimum. Remarkably, some of these optimum settings differ significantly from those used in previously published applications, revealing their unexplored potential. Their applicability in large compound database was also explored by comparing the equivalence of the results obtained using either computed or projected principal properties. In general, the results of the study confirm the suitability of the GRIND-PP for practical applications and provide useful hints about how they should be computed for obtaining optimum results.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Análise de Componente Principal , Interface Usuário-Computador , Bases de Dados de Proteínas , Desenho de Fármacos , Estudos de Viabilidade , Ligantes , Controle de Qualidade
10.
Appl Radiat Isot ; 146: 139-144, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30826494

RESUMO

Optical, chemical, and radiation shielding characteristics of 6 types of Mexican onyx from the semi-desert of Zacatecas have been determined. Onyx samples are Yellow, Blue, Brown, Orange, Red and Green. Characterization was carried out using Energy dispersed X-Ray fluorescence, Visible Ultraviolet Spectrometry and Infrared Spectroscopy. With these techniques it was possible to study the chemical, physical and optical characteristics of the Mexican Onyx; from where the elemental composition was obtained, the absorption peaks, the vibrational modes and the optical band gap. As well as the interactions of these materials with radiation was studied. From this last study we obtained the Mass interaction coefficient for the coherent and incoherent dispersion, the photoelectric effect, the Compton scattering and the pair production, in the atomic nucleus and the electron field. For all types of onyx the total mass attenuation coefficients are alike showing a resonance due to K-shell of Ca. Mexican onyx has a good shielding features to photons of energy less than 100 keV because the most probable event is the photoelectric effect.

11.
Appl Radiat Isot ; 147: 129-135, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30877942

RESUMO

This manuscript presents the design and implementation of an intellectual property core, which acts as a generator of nuclear pulses. The design is embedded in a Field programmable gate array. It is capable of forming pulses with an exponential shape such as those from a radiation detector or Gaussian-shaped pulses such as those provided by a spectroscopy amplifier. Its characteristic is that the amplitude and period of these pulses can be configured by the user through a Virtual instrument generated in graphic language through the LabVIEW development platform. This can greatly reduce the volume, cost and energy consumption in relation to commercial analog nuclear electronics pulse generators.

12.
Appl Radiat Isot ; 147: 31-34, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30798202

RESUMO

X-ray images used for radio-diagnosis are very useful to evaluate the progress of a treatment or to have a better diagnosis. However, during the interaction between the incoming X-ray beam and the body surface, part of the radiation is scattered out reaching other parts of the body delivering an undesirable dose. In this work the dose in eye lenses, thyroid, and gonads of a solid water phantom was measured using thermoluminescent dosimeters, while a Computer Tomography of the torso was obtained. With the measured absorbed dose the effective dose was calculated. Thus, the effective dose in the eye lens, thyroid, and gonads is approximately 57, 214 and 9 µSv respectively. The largest effective dose was on that area located nearest to the region where the radiation is scattered.


Assuntos
Gônadas/efeitos da radiação , Cristalino/efeitos da radiação , Doses de Radiação , Glândula Tireoide/efeitos da radiação , Tomografia Computadorizada por Raios X , Humanos , Espalhamento de Radiação
13.
Appl Radiat Isot ; 146: 57-60, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30753985

RESUMO

In the aim to support treatments and diagnostics in Dentistry the most common radiographies are the periapical radiography and the dental panoramic. In the dental panoramic the X-ray beam is addressed into a large zone of the face obtaining the image of the upper and lower jaw. In this procedure part of the X-rays are scattered reaching some other parts of the patient body. In this work the absorbed dose in the eye lens, thyroid, salivary glands, mammary glands, and gonads, was measured in patients undergoing a dental orthopantomography. Measurements were carried out with thermolmuminiscent dosimeters. With the absorbed doses the Effective dose were calculated. The highest dose was obtained in the salivary glands (30.4 µSv) and the lowest dose was obtained in thyroid (3.8 µSv).


Assuntos
Radiografia Panorâmica/efeitos adversos , Feminino , Gônadas/efeitos da radiação , Humanos , Cristalino/efeitos da radiação , Masculino , Glândulas Mamárias Humanas/efeitos da radiação , Doses de Radiação , Glândulas Salivares/efeitos da radiação , Espalhamento de Radiação , Dosimetria Termoluminescente , Glândula Tireoide/efeitos da radiação
14.
Appl Radiat Isot ; 141: 282-287, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30029828

RESUMO

An multichannel analyzer has been designed, and its performance has been evaluated. The multichannel analyzer is embedded into a Field programmable gate array. The design incudes the virtual instrument in order to hand and to visualize the pulse height spectrum. Two commercially available multichannel analyzers using a NaI(Tl) and HPGe detectors were used to obtain the pulse height spectra of 137Cs, 60Co and 152Eu sources and were compared with the pulse height spectra obtained with the embedded multichannel analyzer, being alike the spectra obtained with the commercial multichannel analyzer. Our design is smaller, low cost and it has options to add other features.

15.
J Ethnopharmacol ; 111(1): 137-41, 2007 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-17140754

RESUMO

In traditional Mexican medicine Cordia curassavica (Jacq) Roemer & Schultes is used to treat gastrointestinal, respiratory and dermatological disorders in Zapotitlán de las Salinas, Puebla (México). The aim of this work was to investigate antimicrobial activity of the essential oil, obtained by using Clevenger distillation apparatus, and hexane, chloroform and methanol extracts from aerial parts of Cordia curassavica. Antimicrobial activity was evaluated against 13 bacteria and five fungal strains. The oil and extracts exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria and five fungal strains. Sarcina lutea and Vibrio cholerae were the strains more sensitive to the essential oil effect (MIC=62 microg/mL) and Vibrio cholerae for the hexane extract (MIC=125 microg/mL). Rhyzoctonia solani was the strain more sensitive to the essential oil effect (IC(50)=180 microg/mL) and Trichophyton mentagrophytes for the hexane extract (IC(50)=230 microg/mL). The essential oil was examined by GC and GC-MS. A total 11 constituents representing 96.28% of the essential oil were identified: 4-methyl,4-ethenyl-3-(1-methyl ethenyl)-1-(1-methyl methanol)cyclohexane (37.34%), beta-eudesmol (19.21%), spathulenol (11.25%) and cadina 4(5), 10(14) diene (7.93%) were found to be the major components. The present study tends to confirm the use in the folk medicine of Cordia curassavica in gastrointestinal, respiratory and dermatological diseases.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Cordia , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Animais , Antibacterianos/química , Antibacterianos/toxicidade , Antifúngicos/química , Antifúngicos/toxicidade , Artemia/efeitos dos fármacos , Fracionamento Químico , Clorofórmio/química , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/crescimento & desenvolvimento , Hexanos/química , Dose Letal Mediana , Metanol/química , México , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Voláteis/toxicidade , Componentes Aéreos da Planta , Extratos Vegetais/farmacologia , Óleos de Plantas/química , Óleos de Plantas/toxicidade , Solventes/química
16.
Psicothema ; 18(4): 724-9, 2006 Nov.
Artigo em Espanhol | MEDLINE | ID: mdl-17296109

RESUMO

Social learning of optimal responding and producer-scrounger strategies in flocks of pigeons. This experiment evaluated the effect of varying the effort required in order to access food upon the acquisition of a novel response, and upon utilizing producer-scrounger strategies, in flocks of pigeons exposed to an expert conspecific. Flocks of naïve observers were exposed to a pigeon trained to open the seals on food deposits. The colors of the seals were correlated with differing required efforts. Later, the trained pigeon was removed while the color-effort correlation was maintained. The results showed that the observers acquired the response of opening the seals and that they executed it discriminatingly, responding in a greater proportion to the color that signaled the least required effort. They also assumed the roles of both producers and scroungers, which varied as a function of the composition of the group. The data obtained are congruent with prior findings regarding social learning, and also with the concepts proposed by the optimal foraging theory.


Assuntos
Columbidae/fisiologia , Comportamento Alimentar/psicologia , Comportamento Imitativo , Aprendizagem , Animais , Cor , Sinais (Psicologia)
17.
FEBS Lett ; 579(27): 6186-90, 2005 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-16243316

RESUMO

Current progress highlights the role of the yeast cell wall as a highly dynamic structure that responds to many environmental stresses. Here, we show that hyperosmotic shock transiently activates the PKC signaling pathway, a response that requires previous activation of the HOG pathway. Phosphorylation of Slt2p under such conditions is related to changes in the glycerol turnover and is mostly Mid2p dependent, suggesting that changes in cell turgor, mediated by intracellular accumulation of glycerol, are sensed by PKC sensors to promote the cell integrity response. These observations, together with previous results, suggest that yeast cells respond to changes in cellular turgor by remodeling their cell walls.


Assuntos
Glicerol/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteína Quinase C/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Transdução de Sinais , Parede Celular/fisiologia , Pressão Osmótica , Fosforilação
18.
C R Biol ; 328(4): 387-402, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15861826

RESUMO

We study, from a numerical point of view, some properties of a model which describes the evolution of a population of Gambussia affinis. Our model includes sufficiently smooth vital functions. First we select, among four numerical methods of second order, the most appropriate in terms of adaptation to the problem. The most efficient method also reveals new properties of the model for long times, such as the tendency to periodicity, obtained with different initial conditions. We also discuss some advantages and deficiencies of the model.


Assuntos
Ciprinodontiformes/crescimento & desenvolvimento , Modelos Biológicos , Animais , Dinâmica Populacional
19.
FEBS Lett ; 549(1-3): 176-80, 2003 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-12914947

RESUMO

Chitin synthesis occurs in most fungi through the action of different chitin synthase (CS) isoenzymes. In Schizosaccharomyces pombe the chs2(+) gene codes for a protein with significant similarity to CS enzymes, but lacking most of the residues considered to be essential for activity, including the QRRRW domain. Here we show that chs2p is a functional protein that localises to the growing edge of the septum but is not a CS enzyme. Strong over-expression is lethal, while moderate expression leads to a severe defect in septum formation. These results suggest that chs2p has remained through evolution to play an alternative role in septation.


Assuntos
Schizosaccharomyces/enzimologia , Sequência de Aminoácidos , Morte Celular , Parede Celular , Schizosaccharomyces/crescimento & desenvolvimento
20.
Cytometry B Clin Cytom ; 51(1): 14-20, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12500293

RESUMO

BACKGROUND: In recent years important information has accumulated on the genetic alterations present in colorectal tumors. However, thus far few studies have analyzed the impact of numerical abnormalities of chromosomes 17 and 18, which carry the p53 and DCC plus SHAD4/DPC4 genes involved in colorectal cancer, on the clinical and biological behaviors of the disease. METHODS: With the use of interphase fluorescence in situ hybridization (FISH), we analyzed the incidence of numerical abnormalities of chromosomes 17 and 18 in a series of malignant colorectal tumors and explored its potential association with clinicobiological behavior and the prognosis of the disease. For this purpose, 94 consecutive patients newly diagnosed with colorectal cancer were analyzed. In all cases, FISH analyses of the number of copies and nuclei of chromosomes 17 and 18 were performed in interphase nuclei with the use of double stainings. For all patients, information on age, sex, tumor size, Dukes' stage, tumor localization, DNA ploidy status, and the proportion of S-phase tumor cells was recorded. Median follow-up was 38 months. RESULTS: Numerical abnormalities of chromosomes 17 and 18 were present in most patients with colorectal cancer (57% and 52%, respectively). Gains of chromosome 17 and monosomy 18 were found in 51% and 29% of cases, respectively, and they were the most frequent individual abnormalities for each chromosome. The simultaneous analysis of the number of copies of both chromosomes in the same cell showed that, in most cases displaying numerical abnormalities for these chromosomes, two or more different tumor cell clones were present. From a clinical point of view, numerical abnormalities of chromosome 17, especially monosomy 17, were associated with a significantly higher incidence of rectal tumors (P = 0.001) and Dukes' stage D (P = 0.02) and a lower median of disease-free survival among patients who underwent curative surgery (P = 0.05), as compared with diploid cases. In addition, cases with an altered number of copies of chromosome 17 showed a higher incidence of DNA aneuploidy (P = 0.0001) and a greater proportion of S-phase cells (P = 0.001) by flow cytometry. In contrast, no clear association was found between the presence of numerical abnormalities of chromosome 18 and clinicobiological disease characteristics, except for a higher incidence of DNA aneuploidy by flow cytometry (P = 0.001) and a lower median of disease-free survival (P = 0.06). Multivariate analysis showed that numerical abnormalities of chromosome 17, but not of chromosome 18, are an independent prognostic factor for predicting disease-free survival in patients with colorectal cancer. CONCLUSIONS: Numerical abnormalities of chromosomes 17 and 18 were relatively common findings in patients with colorectal cancer, with chromosome 17 being associated with a higher incidence of tumors localized to the rectum and a worse clinical outcome. Cytometry Part B (Clin. Cytometry) 51B:14-20, 2003.


Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 17 , Cromossomos Humanos Par 18 , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Citometria de Fluxo , Genes DCC/genética , Genes p53/genética , Humanos , Hibridização in Situ Fluorescente , Incidência , Masculino , Pessoa de Meia-Idade , Prognóstico
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