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1.
Med Mycol ; 60(5)2022 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-35604675

RESUMO

Although a high prevalence of COVID-19-associated pulmonary aspergillosis has been reported, it is still difficult to distinguish between colonization with Aspergillus fumigatus and infection. Concomitantly, similarities between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and hypersensitivity pneumonitis were suggested. The objective of this study was to investigate retrospectively if precipitin assays targeting A. fumigatus could have been useful in the management of SARS-CoV-2 patients hospitalized in an Intensive Care Unit (ICU) in 2020. SARS-CoV-2 ICU patients were screened for Aspergillus co-infection using biomarkers (galactomannan antigen, qPCR) and culture of respiratory samples (tracheal aspirates and bronchoalveolar lavage). For all these patients, clinical data, ICU characteristics and microbial results were collected. Electrosyneresis assays were performed using commercial A. fumigatus somatic and metabolic antigens. ELISA were performed using in-house A. fumigatus purified antigen and recombinant antigens.Our study population consisted of 65 predominantly male patients, with a median ICU stay of 22 days, and a global survival rate of 62%. Thirty-five patients had at least one positive marker for Aspergillus species detection. The number of arcs obtained by electrosyneresis using the somatic A. fumigatus antigen was significantly higher for these 35 SARS-CoV-2 ICU patients (P 0.01, Welch's t-test). Our study showed that SARS-CoV-2 ICU patients with a positive marker for Aspergillus species detection more often presented precipitins towards A. fumigatus. Serology assays could be an additional tool to assess the clinical relevance of the Aspergillus species in respiratory samples of SARS-CoV-2 ICU patients. LAY SUMMARY: This study showed retrospectively that precipitin assays, such as electrosyneresis, could be helpful to distinguish between colonization and infection with Aspergillus fumigatus during the management of severe acute respiratory syndrome Coronavirus-2 (SARS CoV-2) patients in an intensive care unit.


Assuntos
COVID-19 , Aspergilose Pulmonar Invasiva , Animais , Antígenos de Fungos , Aspergillus , Aspergillus fumigatus , Biomarcadores , COVID-19/diagnóstico , COVID-19/veterinária , Feminino , Aspergilose Pulmonar Invasiva/diagnóstico , Aspergilose Pulmonar Invasiva/veterinária , Masculino , Precipitinas , Estudos Retrospectivos , SARS-CoV-2
2.
Med Mycol ; 59(2): 126-138, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32534456

RESUMO

Interlaboratory evaluations of Mucorales qPCR assays were developed to assess the reproducibility and performance of methods currently used. The participants comprised 12 laboratories from French university hospitals (nine of them participating in the Modimucor study) and 11 laboratories participating in the Fungal PCR Initiative. For panel 1, three sera were each spiked with DNA from three different species (Rhizomucor pusillus, Lichtheimia corymbifera, Rhizopus oryzae). For panel 2, six sera with three concentrations of R. pusillus and L. corymbifera (1, 10, and 100 genomes/ml) were prepared. Each panel included a blind negative-control serum. A form was distributed with each panel to collect results and required technical information, including DNA extraction method, sample volume used, DNA elution volume, qPCR method, qPCR template input volume, qPCR total reaction volume, qPCR platform, and qPCR reagents used. For panel 1, assessing 18 different protocols, qualitative results (positive or negative) were correct in 97% of cases (70/72). A very low interlaboratory variability in Cq values (SD = 1.89 cycles) were observed. For panel 2 assessing 26 different protocols, the detection rates were high (77-100%) for 5/6 of spiked serum. There was a significant association between the qPCR platform and performance. However, certain technical steps and optimal combinations of factors may also impact performance. The good reproducibility and performance demonstrated in this study support the use of Mucorales qPCR as part of the diagnostic strategy for mucormycosis.


Assuntos
Técnicas de Laboratório Clínico/normas , DNA Fúngico/genética , Técnicas de Diagnóstico Molecular/normas , Mucorales/genética , Mucormicose/sangue , Mucormicose/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/normas , Técnicas de Laboratório Clínico/instrumentação , Técnicas de Laboratório Clínico/métodos , França , Hospitais Universitários/estatística & dados numéricos , Humanos , Variações Dependentes do Observador , Reprodutibilidade dos Testes
3.
Occup Med (Lond) ; 69(8-9): 632-634, 2019 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31504833

RESUMO

Hypersensitivity pneumonitis (HP) is a chronic inflammatory lung disease caused by repeated inhalation of antigenic substances. We present a case of metalworking fluids (MWFs)-HP sensitized to Pseudomonas oleovorans in a cystic fibrosis patient. This case illustrates that HP diagnosis remains challenging, especially in patients with another pulmonary disease, and that serodiagnosis contributes to identifying the precise microorganism involved. It also demonstrates that P. oleovorans is an important secondary aetiological agent in MWF-HP, less known than Mycobacterium immunogenum.


Assuntos
Alveolite Alérgica Extrínseca/diagnóstico , Fibrose Cística/complicações , Doenças Profissionais/diagnóstico , Adulto , Alveolite Alérgica Extrínseca/tratamento farmacológico , Alveolite Alérgica Extrínseca/etiologia , Alveolite Alérgica Extrínseca/microbiologia , Antígenos de Bactérias , França , Humanos , Óleos Industriais/microbiologia , Masculino , Metalurgia , Doenças Profissionais/imunologia , Doenças Profissionais/microbiologia , Exposição Ocupacional , Pseudomonas oleovorans/imunologia
5.
Indoor Air ; 24(6): 652-61, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24621176

RESUMO

UNLABELLED: Contrary to hospital exposure, little is known about the indoor fungal exposure of hematology patients at home. The aim of our study was to investigate the mold exposure of hematology patients both at home and at hospital to assess their invasive aspergillosis (IA) risk. Fungal exposure was assessed by quantifying opportunistic molds at hospital during hospitalization and in homes of 53 hematology patients. IA was diagnosed in 13 of 53 patients and invasive fungal infection (IFI) in one patient. In hospital, no opportunistic species, or low levels of opportunistic species, were found in 98% of weekly controls. Only 2% of hematology intensive care unit (ICU) controls showed a high level of Aspergillus fumigatus spores in corridor air. Five patients IA were hospitalized during these periods. Seven dwellings of 53 (5/14 dwellings of patients with IA/IFI and 2/39 dwellings of non-IA patients) had a percentage of A. fumigatus and Aspergillus flavus to total mold (significant predictor variable of IA/IFI in our study, general linear model, P-value = 0.02) as high as 15%. Maintaining a 'zero Aspergillus' goal at hospital is essential, and establishing specific and individually opportunistic mold monitoring at home could help to further reduce the IA risk through continuous surveillance. PRACTICAL IMPLICATIONS: This study emphasizes the fact that preventive measures should not be aimed only at the hospital setting: among patients diagnosed with invasive aspergillosis/invasive fungal infection (IA/IFI), 5 of 14 (36%) were exposed to opportunistic fungal species at home exclusively. Moreover, four of these five patients were living in homes having the highest percentage of Aspergillus fumigatus and Aspergillus flavus (>15%), one of which had 48% of A. fumigatus. Therefore, our work supports the need for a counselor to carry out an environmental survey in patients' homes.


Assuntos
Microbiologia do Ar , Hospedeiro Imunocomprometido , Aspergilose Pulmonar Invasiva/etiologia , Adolescente , Adulto , Idoso , Poluição do Ar em Ambientes Fechados/prevenção & controle , Aspergillus/isolamento & purificação , Aspergillus/patogenicidade , Pré-Escolar , Monitoramento Ambiental , Feminino , Hematologia , Habitação , Humanos , Unidades de Terapia Intensiva , Aspergilose Pulmonar Invasiva/prevenção & controle , Masculino , Pessoa de Meia-Idade , Infecções Oportunistas/etiologia , Infecções Oportunistas/prevenção & controle , Fatores de Risco , Adulto Jovem
6.
HNO ; 62(5): 350-7, 2014 May.
Artigo em Alemão | MEDLINE | ID: mdl-24633388

RESUMO

BACKGROUND: Patients with antiplatelet and antithrombotic therapy (AP/AT) represent a substantial proportion of ear, nose and throat (ENT) patients. Despite the ubiquitous consideration of bleeding and ischemic/thrombembolic risk, no detailed assessment of the perioperative setting in an ENT cohort is available in the literature. OBJECTIVES: The goal of the present work is to give a detailed assessment of patients with AP/AT in an ENT cohort resulting in ENT-specific recommendations for daily routine. MATERIALS AND METHODS: In all, 400 randomized patients were asked regarding analgetic therapy in acute pain. Medical data of 5211 patients who underwent head and neck surgery were analyzed for AP/AT therapy. Therapeutic strategies, the perioperative AP/AT therapy, duration of intensive care treatment and hospitalization (ICT/H), application of erythrocytes and internistic/neurolocigal complication data were analyzed in patients with/without AP/AT. RESULTS: Nearly 75 % of our patients were taking AP/AT due to coronary heart disease (CHD), peripheral arterial disease (PAD), cardiac arrhythmia, or cardiovascular disease (CVD). Patients' questionnaire revealed that 31 % of our patients use acetylsalicylic acid in acute pain, which represents 10 % of the overall AP/AT cohort. Head and neck surgery in patients with AP/AT showed an elevated bleeding frequency (p = 0.006) without an elevated risk for internistic/neurological complications. ICT/H were remarkably prolonged (p = 0.006; p = 0.0004). DISCUSSION: Head and neck surgery in patients with AP/AT can be routinely performed. Indication for intensive care, endotracheal intubation, and tracheostomy should be made generously due to high requirements of airway management in ENT. Ischemic/thrombembolic and bleeding risk requires careful assessment in an interdisciplinary setting.


Assuntos
Anticoagulantes/efeitos adversos , Anticoagulantes/uso terapêutico , Procedimentos Cirúrgicos Otorrinolaringológicos/efeitos adversos , Procedimentos Cirúrgicos Otorrinolaringológicos/estatística & dados numéricos , Inibidores da Agregação Plaquetária/uso terapêutico , Hemorragia Pós-Operatória/epidemiologia , Hemorragia Pós-Operatória/etiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Alemanha/epidemiologia , Humanos , Incidência , Lactente , Masculino , Pessoa de Meia-Idade , Hemorragia Pós-Operatória/prevenção & controle , Fatores de Risco , Resultado do Tratamento , Adulto Jovem
8.
HNO ; 61(1): 52-4, 2013 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-22532278

RESUMO

One week after an acute sinusitis, a male patient developed a hypernasal voice, dysphagia, diplopic images, ataxia and paresthesias. He had paresis of the glossopharyngeal and abducens nerves, weakness of the arms and legs, and reflex deficiency. The neurography showed a motor axonal demyelinating neuropathy, so that the diagnosis of Guillain-Barré syndrome was made. After five courses of plasmapheresis, the symptoms improved rapidly.


Assuntos
Transtornos de Deglutição/diagnóstico , Sinusite Frontal/diagnóstico , Síndrome de Guillain-Barré/diagnóstico , Doenças do Nervo Abducente/diagnóstico , Doenças do Nervo Abducente/terapia , Adulto , Transtornos de Deglutição/terapia , Diplopia/diagnóstico , Diplopia/terapia , Seguimentos , Sinusite Frontal/terapia , Doenças do Nervo Glossofaríngeo/diagnóstico , Doenças do Nervo Glossofaríngeo/terapia , Síndrome de Guillain-Barré/terapia , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Exame Neurológico , Proteínas Nucleares , Plasmaferese , Proteínas de Ligação a RNA , Proteínas Repressoras , Tomografia Computadorizada por Raios X , Paralisia das Pregas Vocais/diagnóstico , Paralisia das Pregas Vocais/terapia , Distúrbios da Voz/diagnóstico , Distúrbios da Voz/terapia
9.
Neurochem Res ; 37(5): 1063-73, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22327943

RESUMO

Social isolation during postnatal development leads to behavioral and neurochemical changes, and a particular susceptibility of the prefrontal cortex to interventions during this period has been suggested. In addition, some studies showed that consumption of a palatable diet reduces some of the stress effects. Therefore, our aim is to investigate the effect of isolation stress in early life on some parameters of oxidative stress and energy metabolism (Na(+),K(+)-ATPase activity, respiratory chain enzymes activities and mitochondrial mass and potential) in prefrontal cortex of juvenile and adult male rats. We also verified if the consumption of a palatable diet during the prepubertal period would reduce stress effects. The results showed that, in juvenile animals, isolation stress increased superoxide dismutase and Complex IV activities and these effects were still observed in the adulthood. An interaction between stress and diet was observed in catalase activity in juveniles, while only the stress effect was detected in adults, reducing catalase activity. Access to a palatable diet increased Na(+),K(+)-ATPase activity in juveniles, an effect that was reversed after removing this diet. On the other hand, isolation stress induced a decreased activity of this enzyme in adulthood. No effects were observed on glutathione peroxidase, total thiols and free radicals production, as well as on mitochondrial mass and potential. In conclusion, isolation stress in the prepubertal period leads to long-lasting changes on antioxidant enzymes and energetic metabolism in the prefrontal cortex of male rats, and a palatable diet was not able to reverse these stress-induced effects.


Assuntos
Córtex Pré-Frontal/metabolismo , Isolamento Social , Estresse Psicológico , Animais , Catalase/metabolismo , Transporte de Elétrons , Glutationa Peroxidase/metabolismo , Masculino , Potenciais da Membrana , Mitocôndrias/metabolismo , Córtex Pré-Frontal/enzimologia , Ratos , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismo
10.
J Clin Microbiol ; 49(3): 1058-63, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21227993

RESUMO

The aim of the present study was to assess the diagnostic efficacy of a combination of two quantitative Aspergillus PCR assays, targeting a mitochondrial and a ribosomal target, in patients with risk factors for invasive aspergillosis (IA) and positive galactomannan (GM) antigen. Forty-four patients with hematological malignancies and risk factors for IA according to revised European Organization for Research on Treatment of Cancer and the Mycoses Study Group criteria (EORTC/MSG) criteria and presenting at least two sequential GM-positive sera were included in the study. Mitochondrial PCR was carried out prospectively on all GM-positive serum samples. Ribosomal PCR was carried out retrospectively on frozen stored sera. The sensitivities of mitochondrial and ribosomal PCRs were 58% and 50%, respectively. The diagnostic test performance was improved by using a combination of both PCR assays and by considering a patient PCR positive when at least two positive results were obtained. The sensitivity, specificity, and positive and negative likelihood ratios were 65%, 94%, and 11.8 and 0.37, respectively. A significant association between fatal outcome at 90 days and positive results of ribosomal PCR assays was observed (adjusted hazard ratio = 8.2; 95% confidence interval [CI] = 1.0 to 65.8; P = 0.048). Our results showed that the combination of two PCR assays targeting mitochondrial and ribosomal Aspergillus DNA improves the sensitivity of PCR in the diagnosis of IA in hematological patients with risk factors and positive GM results. This study also confirms that a positive PCR result is associated with a poor prognosis in these patients and should lead to specific antifungal therapy being introduced immediately.


Assuntos
Aspergillus/isolamento & purificação , DNA Fúngico/genética , DNA Mitocondrial/genética , DNA Ribossômico/genética , Aspergilose Pulmonar Invasiva/diagnóstico , Micologia/métodos , Reação em Cadeia da Polimerase/métodos , Adolescente , Adulto , Idoso , Aspergillus/genética , Criança , DNA Fúngico/isolamento & purificação , DNA Mitocondrial/isolamento & purificação , DNA Ribossômico/isolamento & purificação , Feminino , Galactose/análogos & derivados , Humanos , Masculino , Mananas/sangue , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Adulto Jovem
11.
Science ; 293(5530): 683-7, 2001 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-11474108

RESUMO

Well-defined constants of radioactive decay are the cornerstone of geochronology and the use of radiogenic isotopes to constrain the time scales and mechanisms of planetary differentiation. Four new determinations of the lutetium-176 decay constant (lambda176Lu) made by calibration against the uranium-lead decay schemes yield a mean value of 1.865 +/- 0.015 x 10(-11) year(-1), in agreement with the two most recent decay-counting experiments. Lutetium-hafnium ages that are based on the previously used lambda176Lu of 1.93 x 10(-11) to 1.94 x 10(-11) year(-1) are thus approximately 4% too young, and the initial hafnium isotope compositions of some of Earth's oldest minerals and rocks become less radiogenic relative to bulk undifferentiated Earth when calculated using the new decay constant. The existence of strongly unradiogenic hafnium in Early Archean and Hadean zircons implies that enriched crustal reservoirs existed on Earth by 4.3 billion years ago and persisted for 200 million years or more. Hence, current models of early terrestrial differentiation need revision.

12.
Lett Appl Microbiol ; 49(2): 260-6, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19486284

RESUMO

AIMS: The aim of our study was to compare, using real-time (Rt) PCR, quantitative levels of five fungal species in three kinds of dwellings. METHODS AND RESULTS: Three groups of homes were recruited: moisture-damaged homes (MDH, n = 30), allergic patient homes (APH, n = 25) and paired control homes (CH, n = 55). Five moulds with allergenic compounds or mycotoxin production characteristics (Cladosporium sphaerospermum, Penicillium chrysogenum, Aspergillus versicolor, Alternaria alternata and Stachybotrys chartarum) were quantified using Rt-PCR. Cycle threshold results were expressed in spore equivalent per volume or surface unit using a direct calculation based on a spore standard curve. MDH presented significantly higher amounts of DNA from C. sphaerospermum in both air and surface samples than CH (P < 0.001). APH presented slightly elevated amounts of DNA from A. versicolor in both air and surface samples, compared to CH (P < 0.05). CONCLUSION: Rt-PCR quantification of targeted fungal species is a rapid, reliable tool that could be included in a global indoor mould evaluation. SIGNIFICANCE AND IMPACT OF THE STUDY: Quantification of C. sphaerospermum using Rt-PCR can help to better target social service intervention in MDH. Quantification of A. versicolor DNA could be informative for characterization of APH.


Assuntos
Microbiologia Ambiental , Fungos/classificação , Fungos/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Contagem de Colônia Microbiana/métodos , Fungos/genética , Habitação , Humanos
13.
HNO ; 57(8): 808-11, 2009 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-19618128

RESUMO

A 56-year-old female patient presented with a 3-day-old odynophagy and a painful swelling in the left side of the neck. In addition to reddening and swelling of the left side of the neck, which was painful on palpation, leukocytosis and increased C-reactive protein (CRP) and fibrinogen levels were also found. Enlarged lymph nodes along the left vessel-nerve sheath and thrombosis of the internal jugular vein were detected by sonography and computed tomography. The patient could be identified as a heterozygote carrier of the factor V Leiden mutation. This mutation has a thrombotic characteristic due to resistance to activated protein C (APC). Subacute lymphadenitis was an additional disruptive factor and led to thrombosis in the internal jugular vein. The patient received antibiotic treatment and Marcumar, which is planned to be given for a 3-month period.


Assuntos
Linfadenite/complicações , Linfadenite/diagnóstico , Cervicalgia/diagnóstico , Cervicalgia/etiologia , Pescoço , Feminino , Humanos , Pessoa de Meia-Idade
14.
HNO ; 57(9): 959-63, 2009 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-19696974

RESUMO

We report on a 48-year old female patient suffering from recurrent suppurative sialo-adenitis. Resections of both parotid and the left submandibular glands had to be performed due to abscesses. The woman had suffered from recurrent swelling of the salivary glands as well as xerostomia and xerophthalmia for years. Sjögren's syndrome was diagnosed with a delay of 17 years. The current case implicates recurrent bacterial suppurative sialo-adenitis caused by longstanding Sjögren's syndrome. In every case rheumatic disorders have to be considered in the differential diagnosis of recurrent suppurative parotitis. A detailed anamnesis, ultrasound, a differential hemogram, testing for rheumatoid factor and anti-nuclear antibodies (ANA) as well as SS-A and SS-B ENAs can give early information years before Sjögren's syndrome becomes clinically apparent.


Assuntos
Abscesso/diagnóstico , Abscesso/cirurgia , Doenças Parotídeas/diagnóstico , Doenças Parotídeas/cirurgia , Síndrome de Sjogren/diagnóstico , Síndrome de Sjogren/cirurgia , Feminino , Humanos , Pessoa de Meia-Idade , Prevenção Secundária , Resultado do Tratamento
15.
Clin Exp Immunol ; 154(1): 6-14, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18761662

RESUMO

From 19 to 21 May 2008 an important meeting was held at the Pasteur Institute in Paris to mark the 25th Anniversary of the discovery of HIV as the aetiological agent of AIDS. This review summarizes the historical findings, recent work and future directions presented at this meeting.


Assuntos
Infecções por HIV/virologia , HIV/patogenicidade , Vacinas contra a AIDS/uso terapêutico , Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Genes Virais , Predisposição Genética para Doença , HIV/genética , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Humanos
18.
Cancer Res ; 37(6): 1702-8, 1977 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-870184

RESUMO

On the basis of the multi-hit concept of cancer formation, the relationships between tumor incidence and dose and time of administration of carcinogen have been analyzed. Simple mathematics have been used, since the available data, in our opinion, hardly justify more sophisticated formularization. The exponential relationship between the cumulative tumor incidence and the dose and time of administration of carcinogen can be described as l(d,t) approximately dmtr. With use of Druckrey's formula, dtn=k, it was derived that the exponent of time, r, is equal to m-n, in which m is the power of the dose dependency of tumor formation [l(d) approximately dm measured at a fixed time] and n is the autonomous time factor featured in the former formula. The factor m is interpretable in terms of the number of discrete events (hits) required for tumor formation, whereas the factor n is mainly determined by the rate of proliferation of intermediate cell populations participating in the carcinogenic process. Since r and n can be experimentally determined, the formula allows the calculation of the exponent (m) of the dose dependency of tumor formation. Analysis of malignant liver tumor formation in the rat by continuous administration of diethylnitrosamine yeilded m = 7, from which it was concluded that seven hits were instrumental in the induction of these liver-cell tumors. Analysis of the formation of less malignant liver tumors after one pulse exposure to the same carcinogen suggested that the process was initiated by at most two concomitant hits in a liver cell and brought to completion by three spontaneous events (changes). The view was advanced that tumor formation in general may result from hits inflicted by the carcinogen applied and from "background" hits (i.e., spontaneous changes and/or hits by carcinogenic stimuli from the environment or present endogenously) and that the relative contribution of these two types of hits to the end effect may depend on dose level and potency of the carcinogen under consideration. It was pointed out that the direct measurement of the dose-response relation (l(d) approximately dm) yields only the number of hits contributed by the carcinogen applied anose rate is low or very low, the contribution of background process becomes significant, and these hits contribute to the power of time, r, of the incidence-time relation. Under these conditions, the formula m-n=r becomes (mex + mb)n=r, where mex and mb denote the number of hits scored by extrinsic carcinogen and background processes, respectively. It is argued that the epidemiological data on lung cancer caused by smoking [l(d) approximately d with respect to smoke dose, mex= 1; l(t) approximately t5 with respect to duration of smoking] are not compatible unless at least one additional background hit (mb greater than or equal to 1) is postulated...


Assuntos
Neoplasias Hepáticas/induzido quimicamente , Neoplasias Pulmonares/induzido quimicamente , Animais , Carcinógenos/administração & dosagem , Transformação Celular Neoplásica , Dietilnitrosamina/administração & dosagem , Relação Dose-Resposta a Droga , Humanos , Cinética , Matemática , Neoplasias Experimentais/induzido quimicamente , Fumar/complicações
19.
Cancer Res ; 36(7 PT 2): 2544-54, 1976 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-132270

RESUMO

A single application of various hepatocarcinogens to rats results in the formation of islands of enzyme-deficient liver cells, which are mainly irreversible and very probably represent the first cellular stage involved in the process of liver cancer formation. Comparison of the island-size distributions obtained for different carcinogens indicated that proliferation is a common property of islands that is independent of the inducing carcinogen and does not need any further presence of carcinogen or other stimulating factors. Toxic doses resulted in all cases in an enhanced island size. The number of islands induced by a single dose of carcinogen was enhanced by a prior partial hepatectomy only in the case of the dialkylnitrosamines, dimethylnitrosamine, and diethylnitrosamine. Dose-response relationships measured with diethylnitrosamine, the carcinogen with the lowest toxicity as compared with the carcinogenic action, indicated that island formation is due to a one-hit process, i.e., that one specific alteration in the target cell is responsible for the precancerous transformation. These kinetics and the low probability of transformation might indicate that the crucial hit is scored at the genetic level. The irreversible action of carcinogen (memory effect) and the influence of time on cancer formation (time effect) are discussed in terms of induction and proliferation of irreversible cell populations serving as precursor of the cancer cell. The number of specific alterations (hits) involved in the development of the malignant cancer cell is also briefly discussed.


Assuntos
Adenosina Trifosfatases/deficiência , Neoplasias Hepáticas/enzimologia , Lesões Pré-Cancerosas/enzimologia , Animais , Carcinógenos , DNA Nucleotidiltransferases/fisiologia , Dietilnitrosamina/administração & dosagem , Relação Dose-Resposta a Droga , Hiperplasia/enzimologia , Cinética , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/etiologia , Mutação , Neoplasias Experimentais , Fenótipo , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Ratos
20.
Cancer Res ; 47(24 Pt 1): 6719-25, 1987 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-3315190

RESUMO

Calf thymus DNA was modified in vitro by cis-diamminedichloroplatinum(II) (cisDDP), complexed with methylated bovine serum albumin and used to immunize rabbits. The anti-cisDDP-DNA antiserum obtained was applied in a double peroxidase-antiperoxidase staining procedure to localize cisDDP-DNA and cis-diammine(1,1-cyclobutanedicarboxylato)platinum(II) (CBDCA)-DNA interaction products in cryostat tissue sections of mice and rats. Rats received cisDDP (0-10 mg/kg) and were killed after 24 h. Mice received cisDDP (0-15 mg/kg) or CBDCA (200 mg/kg), and were killed after 2 h-162 days. For each time-dose combination two mice or one rat were used; agents were given i.p. Specific nuclear staining was observed in all tissues examined from cisDDP- or CBDCA-treated animals. No significant nuclear staining could be observed in tissue sections from control rats and mice. The extent of staining after cisDDP was dose and time dependent. The lowest dose of cisDDP after which specific nuclear staining could be detected varied from tissue to tissue [e.g., 0.1 mg/kg, pancreas (mouse); 0.5 mg/kg, liver, kidney (mouse, rat)]. The longest time interval after a single dose of 6 mg/kg cisDDP in which adducts could be visualized also depended on the tissue and varied between 9 days (spleen, testis) and 162 days (kidney). The staining intensity in liver and kidney, measured microdensitometrically, decreased relatively fast in the first days after treatment, but much slower thereafter. In the kidney, cisDDP-induced DNA modification showed regional variation: inner cortex greater than outer cortex greater than medulla (rat) and cortex greater than medulla (mouse). In the mouse kidney, a small subpopulation of tubular cells in close association with the renal corpuscles showed a remarkably high staining intensity after both cisDDP and CBDCA administration. Tissues that showed clear cisDDP-induced histological alterations (kidney, pancreas, testis, and duodenum) also showed moderate to high levels of cisDDP-DNA interaction products. A correlation between cell damage (measured histologically) and cisDDP-DNA binding within one tissue type was demonstrated in the rat inner renal cortex, the murine renal cortex, and in duodenal epithelial cells of both mice and rats.


Assuntos
Cisplatino/análise , DNA/análise , Compostos Organoplatínicos/análise , Animais , Carboplatina , Imuno-Histoquímica , Rim/análise , Masculino , Músculos/análise , Pâncreas/análise , Ratos , Ratos Endogâmicos
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