Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 106
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Mycopathologia ; 177(3-4): 207-15, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24570039

RESUMO

Paracoccidioides brasiliensis, a dimorphic pathogenic fungus, causes the principal form of systemic mycosis in Brazil. The literature furnishes only limited data on the ecology of this fungus in the state of Rio Grande do Sul, the southernmost state of Brazil. The purpose of this study was to evaluate the prevalence of fungal infection in wild animals, using serological tests and using the animals as sentinels of the presence of P. brasiliensis in three specified mesoregions of Rio Grande do Sul. A total of 128 wild animals from the three mesoregions were included in the study. The serum samples were evaluated by immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) technique to detect anti-gp43 antibodies from P. brasiliensis. Two conjugates were tested and compared with the ELISA technique. Although no positive samples were detected by immunodiffusion, 26 animals (20%), belonging to 13 distinct species, were found to be seropositive by the ELISA technique. The seropositive animals were from two mesoregions of the state. The results were similar according to the gender, age, and family of the animals, but differed significantly according to the conjugate used (p < 0.001), showing more sensitivity to protein A-peroxidase than to protein G-peroxidase. The finding that wild animals from the state of Rio Grande do Sul are exposed to P. brasiliensis suggests that the fungus can be found in this region despite the often-rigorous winters, which frequently include below-freezing temperatures.


Assuntos
Animais Selvagens/microbiologia , Paracoccidioides/isolamento & purificação , Paracoccidioidomicose/veterinária , Animais , Animais Selvagens/sangue , Animais Selvagens/classificação , Anticorpos Antifúngicos/sangue , Brasil/epidemiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Masculino , Paracoccidioides/classificação , Paracoccidioides/genética , Paracoccidioides/imunologia , Paracoccidioidomicose/sangue , Paracoccidioidomicose/epidemiologia , Paracoccidioidomicose/microbiologia , Vigilância de Evento Sentinela/veterinária , Estudos Soroepidemiológicos
2.
Minerva Ginecol ; 63(2): 171-80, 2011 Apr.
Artigo em Italiano | MEDLINE | ID: mdl-21508905

RESUMO

AIM: The aim of this paper was to compare two anti-incontinence procedures during laparoscopic sacrocolpopexy (LSC) to prevent postoperative stress urinary incontinence (SUI). METHODS: Retrospective analysis of 90 continent hysterectomized patients with vaginal vault prolapse treated with LSC plus colposuspension (group A, N.=30), LSC plus retropubic mid-urethral sling (group B, N.=30), or LSC alone (group C, N.=30). RESULTS: De novo SUI rate resulted significantly (P<0.05) lower in group B than C. No difference was detected regarding de novo urge urinary incontinence. Total reoperation rate resulted significantly (P<0.05) higher in group A than B and lower in group B than C. CONCLUSION: When associated to LSC for preventing SUI, colposuspension and retropubic mid-urethral sling are effective and safe, even if mid-urethral sling seems to provide the best risk/benefit profile.


Assuntos
Laparoscopia , Prolapso de Órgão Pélvico/cirurgia , Slings Suburetrais , Incontinência Urinária por Estresse/prevenção & controle , Feminino , Procedimentos Cirúrgicos em Ginecologia/efeitos adversos , Procedimentos Cirúrgicos em Ginecologia/métodos , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Incontinência Urinária por Estresse/etiologia
3.
Minerva Ginecol ; 63(3): 213-8, 2011 Jun.
Artigo em Italiano | MEDLINE | ID: mdl-21654606

RESUMO

AIM: The aim of this paper was to investigate the sex ratio in the offspring of pregnant patients with polycystic ovary syndrome (PCOS). METHODS: Analysis of 70 pregnant patients with PCOS who achieve a pregnancy without any kind of treatment, and having as controls 63 healthy pregnant women without any feature of PCOS. RESULTS: No significant difference in sex ratio was detected between PCOS and controls, even if it resulted significantly different in the full-blown and non-PCO phenotypes. CONCLUSION: The PCOS phenotypes influenced the sex ratio in the offspring, suggesting that environmental factors could play a role in determination of the offspring gender.


Assuntos
Síndrome do Ovário Policístico/genética , Complicações Neoplásicas na Gravidez/genética , Razão de Masculinidade , Feminino , Humanos , Recém-Nascido , Masculino , Fenótipo , Gravidez
4.
Proc Math Phys Eng Sci ; 477(2245): 20200653, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33633493

RESUMO

This study develops a modelling framework for simulating the spread of infectious diseases within real cities. Digital copies of Birmingham (UK) and Bogotá (Colombia) are generated, reproducing their urban environment, infrastructure and population. The digital inhabitants have the same statistical features of the real population. Their motion is a combination of predictable trips (commute to work, school, etc.) and random walks (shopping, leisure, etc.). Millions of individuals, their encounters and the spread of the disease are simulated by means of high-performance computing and massively parallel algorithms for several months and a time resolution of 1 minute. Simulations accurately reproduce the COVID-19 data for Birmingham and Bogotá both before and during the lockdown. The model has only one adjustable parameter calculable in the early stages of the pandemic. Policymakers can use our digital cities as virtual laboratories for testing, predicting and comparing the effects of policies aimed at containing epidemics.

5.
Phys Rev E Stat Nonlin Soft Matter Phys ; 71(6 Pt 2): 066208, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16089850

RESUMO

Given two time series X and Y , their mutual information, I (X,Y) = I (Y,X) , is the average number of bits of X that can be predicted by measuring Y and vice versa. In the analysis of observational data, calculation of mutual information occurs in three contexts: identification of nonlinear correlation, determination of an optimal sampling interval, particularly when embedding data, and in the investigation of causal relationships with directed mutual information. In this contribution a minimum description length argument is used to determine the optimal number of elements to use when characterizing the distributions of X and Y . However, even when using partitions of the X and Y axis indicated by minimum description length, mutual information calculations performed with a uniform partition of the XY plane can give misleading results. This motivated the construction of an algorithm for calculating mutual information that uses an adaptive partition. This algorithm also incorporates an explicit test of the statistical independence of X and Y in a calculation that returns an assessment of the corresponding null hypothesis. The previously published Fraser-Swinney algorithm for calculating mutual information includes a sophisticated procedure for local adaptive control of the partitioning process. When the Fraser and Swinney algorithm and the algorithm constructed here are compared, they give very similar numerical results (less than 4% difference in a typical application). Detailed comparisons are possible when X and Y are correlated jointly Gaussian distributed because an analytic expression for I (X,Y) can be derived for that case. Based on these tests, three conclusions can be drawn. First, the algorithm constructed here has an advantage over the Fraser-Swinney algorithm in providing an explicit calculation of the probability of the null hypothesis that X and Y are independent. Second, the Fraser-Swinney algorithm is marginally the more accurate of the two algorithms when large data sets are used. With smaller data sets, however, the Fraser-Swinney algorithm reports structures that disappear when more data are available. Third, the algorithm constructed here requires about 0.5% of the computation time required by the Fraser-Swinney algorithm.

6.
Minerva Ginecol ; 67(2): 121-5, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25763801

RESUMO

AIM: Aim of the study was to validate the Hyaluronic acid-Chondroitin sulfate (HA-CS) as ex adiuvantibus criteria to identified patients with urgency symptoms related to interstitial cystitis/painful bladder syndrome (IC/PBS) and to obtained a population of patients with pure stress urinary incontinence. METHODS: We retrospectively analysed clinical data of 17 patients with clinical suspect of IC/PBS, which received intravescical HA-CS to reduce pelvic pain and urgency symptoms waiting for surgical treatment for stress urinary incontinence. The main outcomes were reduction of urinary frequency, urgency, and bladder pain. RESULTS: Compared to baseline, a significant decrease in pain, urgency and frequency were observed. Of the 17 patients, 82.3% reported resolution of pain and urge symptoms and in patients with persistence of urge symptoms the urodynamic assessment showed an overactive bladder syndrome (OAB). CONCLUSION: HA-CS treatment induces an improvement in pain and urgency symptoms in patients with IC/PBS that referred also stress urinary incontinence. Therefore, HA-CS treatment could be use as clinical adjunctive parameter to select patients with pure stress urinary incontinence.


Assuntos
Sulfatos de Condroitina/administração & dosagem , Cistite Intersticial/tratamento farmacológico , Ácido Hialurônico/administração & dosagem , Incontinência Urinária de Urgência/tratamento farmacológico , Adulto , Sulfatos de Condroitina/uso terapêutico , Estudos de Coortes , Cistite Intersticial/fisiopatologia , Combinação de Medicamentos , Feminino , Humanos , Pessoa de Meia-Idade , Dor Pélvica/tratamento farmacológico , Dor Pélvica/etiologia , Estudos Retrospectivos , Resultado do Tratamento , Bexiga Urinária Hiperativa/tratamento farmacológico , Bexiga Urinária Hiperativa/fisiopatologia , Incontinência Urinária por Estresse , Incontinência Urinária de Urgência/diagnóstico , Incontinência Urinária de Urgência/fisiopatologia , Urodinâmica , Adulto Jovem
7.
Chest ; 113(2): 334-9, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9498948

RESUMO

STUDY OBJECTIVES: To verify whether hypoxemia affects respiratory muscle strength in the absence of malnutrition and whether such effect, if present, is reversible with an acute oxygen supplementation. DESIGN: Case series analysis, before-after trial. SETTING: Outpatient pneumology departments of two university hospitals. PATIENTS: One hundred twenty patients affected by COPD in stable conditions having actual to ideal body weight ratio of > or =90%. MEASUREMENTS AND RESULTS: Maximal inspiratory pressure (MIP) was measured at functional residual capacity level in the whole sample of subjects and during oxygen supplementation in 58 patients having a PaO2< or =60 mm Hg when breathing in room air. Predictors of MIP were assessed by a multivariate analysis. MIP values before and after oxygen supplementation were compared by a paired t test. MIP was independently correlated with FVC (p<0.001), PaO2 (p<0.01), and age (p<0.01). In the subgroup of hypoxemic patients, MIP values did not change significantly after oxygen supplementation (3.08+/-1.74 vs 3.03+/-1.91 kPa, t=0.43, not significant). CONCLUSIONS: Hypoxemia is an important negative correlate of MIP even in well-nourished COPD patients. Its effect is not reversible with an acute oxygen supplementation.


Assuntos
Hipóxia/fisiopatologia , Pneumopatias Obstrutivas/fisiopatologia , Contração Muscular/fisiologia , Oxigenoterapia , Músculos Respiratórios/fisiopatologia , Fatores Etários , Idoso , Peso Corporal , Feminino , Seguimentos , Previsões , Capacidade Residual Funcional/fisiologia , Humanos , Hipóxia/terapia , Inalação/fisiologia , Pneumopatias Obstrutivas/terapia , Masculino , Análise Multivariada , Distúrbios Nutricionais , Estado Nutricional , Oxigênio/sangue , Pressão , Análise de Regressão , Volume Residual/fisiologia , Capacidade Pulmonar Total/fisiologia , Capacidade Vital/fisiologia
8.
J Am Acad Child Adolesc Psychiatry ; 39(6): 721-6, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10846306

RESUMO

OBJECTIVES: To examine the efficacy of cognitive-behavioral group therapy for adolescents (CBGT-A) in females with social phobia and the effect of this treatment on the risk for major depression. METHOD: Female adolescents with social phobia (N = 35) were randomly assigned to treatment (n = 12) or no treatment (n = 23) groups. Assessments were conducted at baseline, after treatment, and at a 1-year follow-up. RESULTS: Eleven subjects completed treatment. Sixteen weeks of treatment produced a significant improvement in interference and reduction in symptoms of social anxiety. There was a significant reduction in the number of subjects meeting DSM-IV criteria for social phobia in the CBGT-A versus the untreated group; however, at the 1-year follow-up there were no significant differences by treatment condition. There was also suggestive evidence that treatment of social phobia lowers the risk for relapse of major depression among those with a history of major depression. Combining social phobia and major depression as the outcome produced more robust treatment effects in the 1-year follow-up. CONCLUSIONS: This pilot study provides evidence for a moderate short-term effect of CBGT-A for treating female adolescents suffering from social phobia and indicates that treatment of social phobia may result in a reduction of major depression.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Transtorno Depressivo Maior/prevenção & controle , Transtornos Fóbicos/terapia , Psicoterapia de Grupo/métodos , Adolescente , Distribuição de Qui-Quadrado , Transtorno Depressivo Maior/complicações , Feminino , Seguimentos , Humanos , Transtornos Fóbicos/complicações , Projetos Piloto , Escalas de Graduação Psiquiátrica , Recidiva , Resultado do Tratamento
9.
J Am Acad Child Adolesc Psychiatry ; 40(8): 929-36, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11501693

RESUMO

OBJECTIVE: To examine the level of diagnostic and discriminative accuracy of three dimensional rating scales for detecting anxiety and depressive disorders in a school-based survey of 9th grade youths. METHOD: Classroom screening instruments, the Center for Epidemiologic Studies-Depression Scale (CES-D), the Revised Children's Manifest Anxiety Scale (RCMAS), and the Multidimensional Anxiety Scale for Children (MASC) were administered to 632 youths from three sites in 1998. On the basis of rating scale results, samples of high-scoring and non-high-scoring youths were invited to participate in a diagnostic interview conducted within 2 months of the screening sessions. RESULTS: MASC scores were most strongly associated with individual anxiety disorders, particularly among females, whereas the CES-D composite score was associated with a diagnosis of major depression, after controlling for comorbid disorders. The RCMAS was least successful in discriminating anxiety and depression. When receiver operator characteristic curves were examined, diagnostic accuracy was moderate. CONCLUSIONS: The ability of the MASC and CES-D to discriminate within and between categorically defined diagnostic groups has important implications for the accurate identification of youths in need of services.


Assuntos
Ansiedade/diagnóstico , Depressão/diagnóstico , Programas de Rastreamento/métodos , Escalas de Graduação Psiquiátrica/normas , Adolescente , Ansiedade/epidemiologia , Comorbidade , Depressão/epidemiologia , Feminino , Seguimentos , Humanos , Masculino , Vigilância da População , Valor Preditivo dos Testes , Curva ROC , Análise de Regressão , Projetos de Pesquisa , Instituições Acadêmicas , Distribuição por Sexo , Fatores Sexuais , Estados Unidos/epidemiologia
10.
Free Radic Res ; 22(3): 275-83, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7757202

RESUMO

Cystine markedly enhanced the cytotoxic response of Escherichia coli cells to concentrations of hydrogen peroxide resulting in mode one killing, but displayed little effect in mode two killed cells. The effect of cystine was concentration-dependent over a range of 5-50 microM and did not further increase at higher levels. Cystine had similar effects in other bacterial systems. In order to sensitize the cells to the oxidative injury, the amino acid must be present during exposure to the oxidant since no enhancement of the cytotoxic response can be observed in cystine pre-loaded cells. In addition, no further enhancement of cytotoxicity could be detected when cystine was added before and left during challenge with the oxidant. The enhancing effect of cystine on oxidative injury of E. coli cells appears to be directly mediated by the amino acid and in fact cysteic acid, the most likely oxidation product, had no effect on the killing of bacterial cells elicited by hydrogen peroxide. Other disulfide compounds such as oxidized glutathione, cystamine and dithionitrobenzoic acid only slightly increased the susceptibility of bacteria to the oxidant. The effect of the disulfides was not concentration-dependent over a range of 200-800 microM and was statistically significant only for cystamine. Taken together, these results indicate that cystine markedly increases the cytotoxic response of bacteria to hydrogen peroxide and suggest that the amino acid might impair the cellular defence machinery against hydrogen peroxide. This effect may involve a thiol-disulfide exchange reaction at the cell membrane level.


Assuntos
Cistina/metabolismo , Escherichia coli/metabolismo , Peróxido de Hidrogênio/farmacologia , Escherichia coli/efeitos dos fármacos , Estresse Oxidativo
11.
J Abnorm Psychol ; 107(1): 74-85, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9505040

RESUMO

The authors sought to define the latent factors associated with childhood anxiety and depression, using a structural equations/confirmatory factor-analytic approach involving multiple informants (i.e., parent and child report) of symptoms. A sample of 216 children and adolescents with diagnoses of an anxiety disorder or comorbid anxiety and mood disorders and their parents were administered measures of childhood fear, anxiety, and depression. Results of comparative modeling best supported 3-factor solutions (fear, anxiety, and depression) that were consistent with recent conceptual models of anxiety and depression (e.g., tripartite model). Results also suggested that 3 widely used measures of childhood negative emotion are conceptually heterogeneous (containing item sets that loaded on different latent factors). Implications for the assessment of childhood negative emotions are discussed.


Assuntos
Ansiedade/diagnóstico , Depressão/diagnóstico , Determinação da Personalidade/estatística & dados numéricos , Adolescente , Ansiedade/psicologia , Criança , Depressão/psicologia , Feminino , Humanos , Masculino , Modelos Estatísticos , Psicometria , Reprodutibilidade dos Testes , Transtornos Somatoformes/diagnóstico , Transtornos Somatoformes/psicologia
12.
Psychiatr Clin North Am ; 18(4): 767-84, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8748380

RESUMO

The development of empirically derived, efficacious treatment methods for the range of anxiety disorders in children and adolescents lags far behind the field of adult anxiety treatment research. Controlled trials of both psychosocial and pharmacologic methods are warranted, and several trials are currently underway. Although the literature in this field is growing, many questions remain regarding the application and long-term benefit of interventions with youth. Specifically, although the field of adult psychosocial treatment research has advanced such that empirically derived treatment protocols are readily available, such methodologies are lacking for anxious youth. Serious attention must turn toward the empirical testing and validation of developmentally appropriate psychosocial treatment protocols. Fortunately, work in this area is currently under way in several centers (e.g., for social phobia, OCD, and generalized anxiety). Moreover, the role of parents in the psychosocial treatment process remains largely unexplored. Investigations are underway examining the effectiveness of training parents in the delivery of particular psychosocial procedures and evaluating the optimal "degree" of parental involvement. Attention also must turn to the systematic study of variables hypothesized to affect negatively the successful integration of parents (e.g., age of child, severity of disorder, parental psychopathology). And lastly, combined trials of pharmacologic compounds and psychosocial interventions are needed to examine the prescriptive treatment approach of matching patients to treatments.


Assuntos
Transtornos de Ansiedade/terapia , Adolescente , Ansiolíticos/administração & dosagem , Transtornos de Ansiedade/classificação , Transtornos de Ansiedade/diagnóstico , Transtornos de Ansiedade/psicologia , Criança , Terapia Combinada , Feminino , Humanos , Masculino , Psicoterapia/métodos , Resultado do Tratamento
13.
Life Sci ; 60(8): 519-28, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9042386

RESUMO

2',3'-Dideoxycytidine (ddC) is a nucleoside analogue currently used in AIDS therapy. We had previously found that long term exposure of U937 human monoblastoid cells to ddC induces the selection of drug-resistant cells (U937-R). In the present work we investigated some important biochemical properties and functional activities of these resistant cells. The results obtained show that U937-R maintained the properties of cell aggregation, adhesion and differentiation. Basal respiration, protein kinase C activity, superoxide anion release and intracellular free calcium were all increased in the drug-resistant line. Phagocytosis of fungi (Candida albicans) and bacteria (Staphylococcus aureus and Salmonella anatum) were similar in U937 and U937-R cells. Killing of C. albicans was significantly higher in drug-resistant cells (29.07 +/- 2.23% of killing vs 19.07 +/- 2.01 in the control; p < 0.001). Similarly, the bacterial killing was enhanced in U937-R cells (34.07 +/- 8.06% vs 22.60 +/- 4.41% in the control; p < 0.05). Thus, the results presented in this paper provide evidence of an increased microbicidal activity of human monocytic cells upon long term exposure to ddC, most likely due to an increased oxidative metabolism.


Assuntos
Atividade Bactericida do Sangue , Monócitos/imunologia , Zalcitabina/farmacologia , Candida albicans , Linhagem Celular , Humanos , Monócitos/efeitos dos fármacos , Fagocitose , Salmonella , Staphylococcus aureus , Acetato de Tetradecanoilforbol/farmacologia
14.
Chem Biol Interact ; 70(3-4): 281-8, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2663198

RESUMO

The toxicity of H2O2 in Escherichia coli wild type and superoxide dismutase mutants was investigated under different experimental conditions. Cells were either grown aerobically, and then treated in M9 salts or K medium, or grown anoxically, and then treated in K medium. Results have demonstrated that the wild type and superoxide dismutase mutants display a markedly different sensitivity to both modes of lethality produced by H2O2 (i.e. mode one killing, which is produced by concentrations of H2O2 lower than 5 mM, and mode two killing which results from the insult generated by concentrations of H2O2 higher than 10 mM). Although the data obtained do not clarify the molecular basis of H2O2 toxicity and/or do not explain the specific function of superoxide ions in H2O2-induced bacterial inactivation, they certainly demonstrate that the latter species plays a key role in both modes of H2O2 lethality. A mechanism of H2O2 toxicity in E. coli is proposed, involving the action of a hypothetical enzyme which should work as an O2-. generating system. This enzyme should be active at low concentrations of H2O2 (less than 5 mM) and high concentrations of the oxidant (greater than 5 mM) should inactivate the same enzyme. Superoxide ions would then be produced and result in mode one lethality. The resistance at intermediate H2O2 concentrations may be dependent on the inactivation of such enzyme with no superoxide ions being produced at levels of H2O2 in the range 5-10 mM. Mode two killing could be produced by the hydroxyl radical in concert with superoxide ions, chemically produced via the reaction of high concentrations of H2O2 (greater than 10 mM) with hydroxyl radicals. The rate of hydroxyl radical production may be increased by the higher availability of Fe2+ since superoxide ions may also reduce trivalent iron to the divalent form.


Assuntos
Escherichia coli/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Superóxido Dismutase/fisiologia , Aerobiose , Anaerobiose , Escherichia coli/genética , Mutação , Superóxido Dismutase/genética
15.
Chem Biol Interact ; 85(2-3): 255-63, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1337313

RESUMO

3T3 mouse embryo fibroblast cell growth was inhibited in a concentration dependent manner by 2',3'-dideoxycytidine (ddCyd), a strong inhibitor of human immunodeficiency virus. Cell growth inhibition was associated with an increased incorporation of ddCyd into cell DNA. In contrast SP2/0-Ag14 (a mouse myeloma) cell growth is not inhibited by 100 microM ddCyd both in the presence or absence of hypoxanthine and thymidine. Furthermore, in vitro spleen cell proliferation, upon phytohemagglutinin (PHA) addition, was much more affected by ddCyd in C57BL/6 mice than in Swiss albino mice. That indeed ddCyd affects spleen cell proliferation was confirmed by studies on splenocytes obtained from C57BL/6 mice that received ddCyd for 2 weeks in drinking water. These results suggest that ddCyd toxicity in mice is cell and strain dependent and that the toxicity mechanism is related to the incorporation of the drug in cell DNA.


Assuntos
Zalcitabina/toxicidade , Células 3T3/efeitos dos fármacos , Animais , Divisão Celular/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Especificidade da Espécie , Baço/citologia , Baço/efeitos dos fármacos
16.
Chem Biol Interact ; 79(1): 53-64, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1647888

RESUMO

U937 human monoblastoid cell growth was inhibited in a concentration-dependent manner by 2',3'-dideoxycytidine (ddCyd) (an antiretroviral drug) up to 500 microM. Cell growth inhibition was associated with a pronounced increase in cell volume, however this was not due to cell ATP or NAD+ depletion that could effect osmotic balance or DNA repair. This ddCyd toxicity paralleled the accumulation of ddCyd into acid soluble material where 2',3'-dideoxycytidine-5'-triphosphate (ddCTP) was the predominant labelled nucleotide up to an extracellular ddCyd concentration of 150 microM. At higher ddCyd concentrations, the amount of 2',3'-dideoxycytidine-5'-diphosphate (ddCDP) became predominant over ddCTP. This increase of phosphorylated dideoxycytidine in U937 cells was also associated with an increased incorporation of the drug into cell DNA suggesting a possible toxicity mechanism. That ddCyd does indeed become cytotoxic to human cell by incorporation into DNA was shown by incubating human resting and stimulated lymphocytes with ddCyd. While the drug does not affect cell viability in resting cells it strongly affects cell proliferation upon phytohemagglutinin (PHA) addition.


Assuntos
Antivirais/toxicidade , Infecções por HIV/tratamento farmacológico , Linfócitos/metabolismo , Zalcitabina/toxicidade , Trifosfato de Adenosina/metabolismo , Antivirais/metabolismo , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Nucleotídeos de Desoxicitosina/metabolismo , Humanos , Técnicas In Vitro , Ativação Linfocitária/efeitos dos fármacos , Monócitos/citologia , Monócitos/efeitos dos fármacos , NAD/metabolismo , Fosforilação , Células Tumorais Cultivadas , Zalcitabina/metabolismo
17.
Mutat Res ; 281(3): 157-61, 1992 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1371836

RESUMO

The effect of cystine in the cytotoxic response of cultured Chinese hamster ovary and Escherichia coli cells to challenge with hydrogen peroxide has been investigated. It was found that this amino acid could either protect or sensitize cells, depending on the cellular system. In fact, although a reduction in the growth-inhibitory effect of hydrogen peroxide was observed in mammalian cells, a marked increase in the susceptibility to oxidative stress was induced by cystine in bacteria. None of the amino acid precursors of glutathione, e.g., glutamate, glycine or cysteine, afforded protection in the mammalian cell system, whereas cysteine, but not glycine or glutamate, markedly sensitized bacteria to hydrogen peroxide-induced cell killing. In mammalian cells, methionine, an amino acid which is converted to cysteine, was also unable to modify the oxidative response. The results presented indicate that cystine displays differential effects in oxidatively injured mammalian or bacterial cells and suggest that the mechanism whereby the amino acid modulates the lethal action of hydrogen peroxide differs in the two cellular systems.


Assuntos
Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cistina/farmacologia , Escherichia coli/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Animais , Células CHO , Cricetinae , Cisteína/farmacologia , Escherichia coli/crescimento & desenvolvimento , Glutamatos/farmacologia , Ácido Glutâmico , Glicina/farmacologia
18.
Phys Rev E Stat Nonlin Soft Matter Phys ; 67(6 Pt 1): 063901; author reply 063902, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16241284

RESUMO

Quian Quiroga et al. [Phys. Rev. E 65, 041903 (2002)] reported a similar performance of several linear and nonlinear measures of synchronization when applied to the rat electrocorticogram (ECoG). However, they found that the mutual information measure did not produce robust estimates of synchronization when compared to other measures. We reexamined their data using a histogram method with adaptive partitioning and found the mutual information to be a useful measure of regional ECoG interdependence.

19.
Phys Rev E Stat Nonlin Soft Matter Phys ; 67(6 Pt 2): 066210, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16241329

RESUMO

Embedding experimental data is a common first step in many forms of dynamical analysis. The choice of appropriate embedding parameters (dimension and lag) is crucial to the success of the subsequent analysis. We argue here that the optimal embedding of a time series cannot be determined by criteria based solely on the time series itself. Therefore we base our analysis on an examination of systems that have explicit analytic representations. A comparison of analytically obtained results with those obtained by an examination of the corresponding time series provides a means of assessing the comparative success of different embedding criteria. The assessment also includes measures of robustness to noise. The limitations of this study are explicitly delineated. While bearing these limitations in mind, we conclude that for the examples considered here, the best identification of the embedding dimension was achieved with a global false nearest neighbors argument, and the best value of lag was identified by the mutual information function.

20.
J Chemother ; 9(3): 208-12, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9210004

RESUMO

In this random study, the efficacy of either colloidal bismuth subcitrate (CBS) or metronidazole in combination with an H2-antagonist in the treatment of various gastric pathologies was evaluated, along with the trends in antibody levels. Among the 40 Helicobacter pylori-positive patients with various gastroduodenal pathologies who underwent chemotherapy, 27 were treated with CBS and 13 with metronidazole. H. pylori was eradicated in 48.14% of the patients treated with CBS and 53.8% of those treated with metronidazole. After therapy, no statistically significant or slight decrease in the serum levels of antibodies was found.


Assuntos
Antibacterianos/uso terapêutico , Antiulcerosos/uso terapêutico , Infecções por Helicobacter/tratamento farmacológico , Antagonistas dos Receptores H2 da Histamina/uso terapêutico , Metronidazol/uso terapêutico , Compostos Organometálicos/uso terapêutico , Adulto , Idoso , Quimioterapia Combinada , Helicobacter pylori/efeitos dos fármacos , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA