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1.
Ann Ig ; 33(1): 21-30, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33354693

RESUMO

BACKGROUND: The fight against antibiotic resistance (AR) is nowadays a world priority. Antibiotic resistance is largely associated with the overuse of antibiotics and a lack of awareness of the problem. Considering the large use of antibiotics in the paediatric age, the aim of this study was to investigate the knowledge and perception of antibiotic resistance in a sample of parents. METHODS: A cross-sectional study was conducted on a sample of parents of children aged 0-14. Data on antibiotic use and awareness of antibiotic resistance were collected by a self-administrated questionnaire. The potential predictors of the antibiotic resistance awareness were evaluated using a multivariate logistic regression model. RESULTS: The questionnaire was completed by 610 parents of which 91% (n=553) used antibiotics for their children. Summarizing the answers related to antibiotic resistance knowledge and perception, 36% of parents gave a correct answers to at least 9 of 12 questions. Fever seemed to represent a reason of anxiety in parents. Using a 10-point scale, the perceived anxiety by parents was measured based on a situation when the child wakes up in the morning with a fever at 38°C and the doctor suggests to wait at least 48 hours before administering the antibiotic. Almost half of parents (49%) indicated a low degree of anxiety (1-4), 31% medium (5-6), and 20% high (7-10). Multivariate analysis showed that a good level of education, healthcare occupation and low grade of anxiety are associated with antibiotic resistance awareness. CONCLUSIONS: The awareness of antibiotic resistance is not strong. The study highlights the need to put effort on tailored education programs aimed to improve knowledge of antibiotic resistance and guide mainly anxious parents to appropriate management of disease of their children.


Assuntos
Antibacterianos , Conhecimentos, Atitudes e Prática em Saúde , Antibacterianos/farmacologia , Criança , Estudos Transversais , Resistência Microbiana a Medicamentos , Humanos , Pais , Inquéritos e Questionários
2.
Public Health ; 182: 179-184, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32334185

RESUMO

OBJECTIVES: We assess the individual willingness to pay for diseases arising from risky lifestyles and investigate the personal factors that influence such willingness. STUDY DESIGN: We conducted an online survey with 821 respondents in Italy. The questionnaire was distributed via Facebook® in July and August 2016. The questionnaire covered sociodemographic characteristics, health status, behaviour and psychological attitudes, economic status, and opinion about covering the healthcare costs related to overeating, unhealthy diet, sedentary lifestyles, alcohol abuse, tobacco smoking, driving under the influence of alcohol, and illegal drug use by. METHODS: We performed the following: (1) the study of the patterns in the dependent variables by principal component analysis; (2) analysis of the determinants by Holdout Variable Importance measure obtained in Random Forest; and (3) we used ordered logit models. RESULTS: Participants agreed with the idea that public health care should be provided for problems arising from bad eating habits and sedentary lifestyle (50.4%), whereas the health care consequences of the other risky behaviours should not be publicly financed by the Italian National Health Service. CONCLUSIONS: Our study gives an overview of the willingness to pay of a population living in a country where financing of the Health Service is based on general taxation. So, these results may be generalized, with due caution, to all the countries where the Health Service offers universal coverage and is operated by the government, but of course not to scenarios related to market-based or social health insurance systems.


Assuntos
Atenção à Saúde/economia , Atenção à Saúde/métodos , Comportamentos de Risco à Saúde , Estilo de Vida , Adolescente , Adulto , Atitude , Dieta , Feminino , Humanos , Itália , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Assunção de Riscos , Comportamento Sedentário , Fatores Socioeconômicos , Medicina Estatal , Inquéritos e Questionários , Adulto Jovem
3.
Ann Ig ; 28(5): 339-48, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27627665

RESUMO

BACKGROUND: The Mediterranean diet (MD) is considered one of the healthiest dietary models, as it decreases the risk of chronic diseases and may modulate the organism's early response to environmental pollution. In recent decades, Mediterranean countries have been replacing their traditional diet with other less healthy eating habits, especially among children and teenagers. OBJECTIVE: The aim of this study was to evaluate the MD and the level of adherence to it in 6-8 year old Italian children, in relation to residence, lifestyle, and social and family contexts. METHODS: A questionnaire was administered to the children's parents in two seasons in 5 Italian towns. The diet section contained 116 questions investigating the frequency of consumption of different types of food. The Italian Mediterranean Index (IMI) was calculated according to the intake of 6 typical Mediterranean and 4 non-Mediterranean foods. On the basis of IMI score, MD adherence was classified as low (≤ 3 IMI score), medium (4-5) and high (≥ 6). Total energy load and diet composition in micro- and macronutrients were calculated from consumption frequency. RESULTS: Diet analysis was computed on 1164 subjects with two complete questionnaires. Body mass index, calculated for each subject, showed that 28.9% of the children were overweight, the figure varying slightly with area of residence. Our findings showed that 59.0% of the children had a low score for MD adherence. CONCLUSIONS: The results of this study showed that most Italian children did not follow the MD and socio-economic characteristics appeared not to be associated with type of diet.


Assuntos
Dieta Mediterrânea , Estilo de Vida , Sobrepeso/epidemiologia , Pais , Cooperação do Paciente/estatística & dados numéricos , Adulto , Índice de Massa Corporal , Criança , Inquéritos sobre Dietas , Comportamento Alimentar , Feminino , Humanos , Itália/epidemiologia , Masculino , Obesidade Infantil/epidemiologia , Pobreza/estatística & dados numéricos , Fatores de Risco , Inquéritos e Questionários
4.
Ann Ig ; 27(4): 646-56, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26241109

RESUMO

INTRODUCTION: The MAPEC-Life project aims to study the biological effects of early exposure to air pollutants on the oral mucosa cells of school-age children in five Italian cities. A questionnaire was created to evaluate the association between outdoor and indoor airborne pollutants, lifestyle, diet and biomarker effects. The feasibility and reliability of the questionnaire were evaluated. METHODS: A questionnaire was drawn up to be filled in by the parents of 6-8-year-old children. It consisted of 148 questions on the children's health, physical activity, environmental exposures and the frequency of food consumption at the main meals. First we conducted a questionnaire feasibility study involving 53 volunteer parents. We then performed a reliability study by administering the questionnaire to a further 156 parents and again one month later (test/retest method). The correlations between answers at the first and second administration of the questionnaire were evaluated using the Kappa statistic and Spearman's coefficient. RESULTS: After verifying the feasibility of the questionnaire, we conducted a reliability analysis on 132 completed questionnaires. The percentage of agreement between the first and the second responses given was over 70%, all K values being greater than 0.6. The analysis of calories and macronutrients also showed good agreement. CONCLUSIONS: The questionnaire drawn up for the study proved to be sufficiently reliable for gathering information about the factors of interest in our study of the relationship between air pollution and early biological effects in children.


Assuntos
Poluição do Ar em Ambientes Fechados , Dieta , Exposição Ambiental , Nível de Saúde , Atividade Motora , Inquéritos e Questionários , Poluição do Ar em Ambientes Fechados/efeitos adversos , Criança , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental/métodos , Estudos de Viabilidade , Feminino , Inquéritos Epidemiológicos , Humanos , Itália , Masculino , Pais , Reprodutibilidade dos Testes
5.
Ann Ig ; 21(2): 153-9, 2009.
Artigo em Italiano | MEDLINE | ID: mdl-19653447

RESUMO

The biomonitoring of genotoxic effects in environmental complex mixtures using higher plants is very useful for hazard evaluation. In this study we evaluated the potential application of plant genotoxicity tests in monitoring mutagens in landfill environment. The clastogenic effects of gaseous emissions (biogas)from three municipal landfills were evaluated by in situ monitoring using the Tradescantia micronucleus assay. The cytotoxicity and genotoxicity of leachates were studied using the Allium cepa test. We found no significant differences in micronuclei frequency in pollen cells of Tradescantia. Leachate samples showed elevated toxicity that inhibited root tip development in Allium cepa. Genotoxicity of the leachates was evaluated in diluted samples only. We found a significant increase in chromosomal metaphase aberrations only in one of the samples analyzed. In conclusion, biogas was not shown to be a real hazard, whereas leachates were found to display elevated toxicity. It would be advisable to treat leachates before releasing them into the environment as they can cause ecological damages. Since plant bioassays are very useful for the in situ monitoring of environmental genotoxins they are important for the prevention of environmental pollution resulting from the disposal of solid waste.


Assuntos
Bioensaio/métodos , Aberrações Cromossômicas/induzido quimicamente , Cromossomos de Plantas/efeitos dos fármacos , Cidades , Monitoramento Ambiental/métodos , Poluentes Ambientais/toxicidade , Mutagênicos/toxicidade , Poluentes Atmosféricos/toxicidade , Monitoramento Ambiental/normas , Humanos , Itália , Meristema/genética , Testes de Mutagenicidade/métodos , Mutagênicos/análise , Cebolas/efeitos dos fármacos , Cebolas/genética , Eliminação de Resíduos/normas , Poluentes do Solo/toxicidade , Tradescantia/efeitos dos fármacos , Tradescantia/genética
6.
Water Res ; 42(15): 4075-82, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18718628

RESUMO

In the last few years chlorine dioxide has been increasingly used for disinfecting drinking water in many countries. Although it does not react with humic substances, chlorine dioxide added to water is reduced primarily to chlorite and chlorate ions, compounds that are under investigation for their potential adverse effects on human health. The aim of this research was to study the genotoxicity of chlorite and chlorate and their mixtures. The end-points included two plant tests (chromosomal aberration test in Allium cepa and micronucleus assay in Tradescantia, carried out at different times of exposure) and two genotoxicity tests in human HepG2 cells (comet assay and cytokinesis-blocked micronucleus test). Preliminary toxicity tests were carried out for both plant and HepG2 assays. The results showed that chlorite and chlorate are able to induce chromosomal damage to plant systems, particularly chromosomal aberrations in A. cepa root tip cells, even at concentrations lower than the limit established by Italian normative law and WHO guidelines. In HepG2 cells increased DNA damage was only observed for chlorate at the lowest concentration. No increase in micronuclei frequency was detected in any of the samples tested in human HepG2 cells.


Assuntos
Cloratos/toxicidade , Cloretos/toxicidade , Dano ao DNA , Bioensaio/métodos , Linhagem Celular Tumoral , Cromossomos de Plantas/efeitos dos fármacos , Cromossomos de Plantas/genética , Ensaio Cometa/métodos , Humanos , Testes para Micronúcleos/métodos , Testes de Mutagenicidade/métodos , Cebolas/efeitos dos fármacos , Cebolas/genética , Tradescantia/efeitos dos fármacos , Tradescantia/genética
7.
Patient Educ Couns ; 100(12): 2231-2243, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28855063

RESUMO

OBJECTIVE: The aim of this systematic review was to find a scientific evidence on the efficacy of apps in promoting healthy lifestyles. METHODS: The research was carried out according to PRISMA Statement. Pubmed, Embase and Google Scholar searches were carried out up to September 2016 focusing on randomized control trials (RCTs). RESULTS: Forty RCTs were selected. Most of the studies targeted weight management, PA and healthy eating (N=35). A few RCTs focused on apps designed to sun protection, smoking cessation and alcohol consumption (N=5). Only 10 RCTs (25%) found statistical difference between intervention and control groups for all the outcomes measured. Most of the studies had a short follow-up (65%, less than 6 months) and half of them a very small sample size (fewer than 100 subjects). CONCLUSION: Overall, the evidence so far showed a modest efficacy of apps in health promotion. PRACTICE IMPLICATIONS: There is a need to improve the overall quality of intervention studies focused on mobile apps in order to understand if they could became a valuable tool in support of health professionals and their efforts to promote education and health.


Assuntos
Telefone Celular , Promoção da Saúde , Estilo de Vida Saudável , Aplicativos Móveis , Sistemas de Alerta/instrumentação , Humanos , Saúde Pública , Ensaios Clínicos Controlados Aleatórios como Assunto , Autocuidado
8.
Water Res ; 102: 211-220, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27344252

RESUMO

The occurrence of emerging organic micropollutants (OMPs) in sewage sludge has been widely reported; nevertheless, their fate during sludge treatment remains unclear. The objective of this work was to study the fate of OMPs during mesophilic and thermophilic anaerobic digestion (AD), the most common processes used for sludge stabilization, by using raw sewage sludge without spiking OMPs. Moreover, the results of analytical chemistry were complemented with biological assays in order to verify the possible adverse effects (estrogenic and genotoxic) on the environment and human health in view of an agricultural (re)use of digested sludge. Musk fragrances (AHTN, HHCB), ibuprofen (IBP) and triclosan (TCS) were the most abundant compounds detected in sewage sludge. In general, the efficiency of the AD process was not dependent on operational parameters but compound-specific: some OMPs were highly biotransformed (e.g. sulfamethoxazole and naproxen), while others were only slightly affected (e.g. IBP and TCS) or even unaltered (e.g. AHTN and HHCB). The MCF-7 assay evidenced that estrogenicity removal was driven by temperature. The Ames test did not show point mutation in Salmonella typhimurium while the Comet test exhibited a genotoxic effect on human leukocytes attenuated by AD. This study highlights the importance of combining chemical analysis and biological activities in order to establish appropriate operational strategies for a safer disposal of sewage sludge. Actually, it was demonstrated that temperature has an insignificant effect on the disappearance of the parent compounds while it is crucial to decrease estrogenicity.


Assuntos
Esgotos/química , Eliminação de Resíduos Líquidos , Anaerobiose , Humanos , Perfumes , Sulfametoxazol , Temperatura
9.
Chemosphere ; 120: 221-9, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25084136

RESUMO

Urban air contains many mutagenic pollutants. This research aimed to investigate the presence of mutagens in the air by short-term mutagenicity tests using bacteria, human cells and plants. Inflorescences of Tradescantia were exposed to air in situ for 6h, once a month from January to May, to monitor volatile compounds and micronuclei frequency was computed. On the same days PM10 was collected continuously for 24h. Half of each filter was extracted with organic solvents and studied by means of the Ames test, using Salmonella typhimurium TA98 and TA100 strains, and the comet assay on human leukocytes. A quarter of each filter was extracted with distilled water in which Tradescantia was exposed. PM10 concentration was particularly high in the winter season (> 50 µg/m(3)). In situ exposure of inflorescences to urban air induced a significant increase in micronuclei frequency at all the sites considered, but only in January (p < 0.01). Aqueous extracts collected in January and February induced genotoxic effects in Tradescantia exposed in the laboratory (p < 0.01). Ames test showed that organic extracts of winter urban air were able to induce genetic mutations in S. typhimurium TA98 strain (± S9), but not in TA100 strain, with a revertants/plate number nine times higher than the negative control. Comet assay showed that winter extracts were more toxic and genotoxic than spring extracts. All the mutagenicity tests performed confirmed that urban air in North Italy in winter contains both volatile and non-volatile genotoxic substances able to induce genetic damage in bacteria, human cells and plants.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Mutagênicos/análise , Poluentes Atmosféricos/toxicidade , Ensaio Cometa , Humanos , Itália , Leucócitos/química , Leucócitos/efeitos dos fármacos , Testes para Micronúcleos , Testes de Mutagenicidade , Mutagênicos/toxicidade , Mutação Puntual/efeitos dos fármacos , Pólen/química , Pólen/efeitos dos fármacos , Salmonella typhimurium/química , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Tradescantia/química , Tradescantia/efeitos dos fármacos
11.
Tumori ; 82(4): 408-12, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8890982

RESUMO

The authors describe a case of undifferentiated rhabdomyosarcoma from unknown primary site, presenting as an acute hematologic malignancy with generalized lymphadenopathy, extensive bone marrow involvement and clinical and laboratory features of disseminated intravascular coagulation. Such a peculiar behaviour is known for rhabdomyosarcoma but is rare and can be a serious diagnostic problem for the clinician and the pathologist. The importance of a large spectrum immunohistochemistry as first diagnostic approach to any undifferentiated small-cell malignant tumor is stressed, together with the knowledge of the different immunoreactivity patterns. Desmin, MS-actin and myoglobin are the most reliable markers of this type of myogenic sarcoma.


Assuntos
Rabdomiossarcoma/diagnóstico , Actinas , Doença Aguda , Adolescente , Braço , Biomarcadores Tumorais , Biópsia , Desmina , Diagnóstico Diferencial , Feminino , Neoplasias Hematológicas/diagnóstico , Humanos , Imuno-Histoquímica , Mioglobina , Neoplasias Primárias Desconhecidas
12.
BMJ Open ; 4(9): e006096, 2014 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-25227631

RESUMO

INTRODUCTION: Genotoxic biomarkers have been studied largely in adult population, but few studies so far have investigated them in children exposed to air pollution. Children are a high-risk group as regards the health effects of air pollution and some studies suggest that early exposure during childhood can play an important role in the development of chronic diseases in adulthood. The objective of the project is to evaluate the associations between the concentration of urban air pollutants and biomarkers of early biological effect in children, and to propose a model for estimating the global risk of early biological effects due to air pollutants and other factors in children. METHODS AND ANALYSIS: Two biomarkers of early biological effects, DNA damage by the comet assay and the micronuclei (MN) test, will be investigated in oral mucosa cells of 6-8-year-old children. Concurrently, some toxic airborne pollutants (polycyclic aromatic hydrocarbon (PAH) and nitro-PAH) and in vitro air mutagenicity and toxicity in ultra-fine air particulates (PM0.5) will be evaluated. Furthermore, demographic and socioeconomic variables, other sources of exposures to air pollutants and lifestyle variables will be assessed by a structured questionnaire. The associations between sociodemographic, environmental and other exposure variables and biomarkers of early biological effect using univariate and multivariate models will be analysed. A tentative model for calculating the global absolute risk of having early biological effects caused by air pollution and other variables will be proposed. ETHICS AND DISSEMINATION: The project has been approved by the Ethics Committees of the local Health Authorities. The results will be communicated to local Public Health Agencies, for supporting educational programmes and health policy strategies. LIFE+2012 Environment Policy and Governance. LIFE12 ENV/IT/000614.


Assuntos
Poluição do Ar/análise , Monitoramento Ambiental , Política de Saúde , Saúde Pública , Criança , Humanos , Estudos Prospectivos
13.
Sci Total Environ ; 458-460: 160-8, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23648445

RESUMO

WWTP (wastewater treatment plant) effluents are considered to be a major source for the release in the aquatic environment of EDCs (Endocrine-Disrupting Compounds), a group of anthropogenic substances able to alter the normal function of the endocrine system. The application of conventional processes (e.g. activated sludge with biological nitrogen removal) does not provide complete elimination of all these micropollutants and, consequently, an advanced treatment should be implemented. This experimental work was conducted on the tertiary ozonation stage of a 140,000 p.e. activated sludge WWTP, treating a mixed domestic and textile wastewater: an integrated monitoring, including both chemical (nonylphenol, together with the parent compounds mono- and di-ethoxylated, and bisphenol A were chosen as model EDCs) and biological (estrogenic and genotoxic activities) analyses, was carried out. Removal efficiencies of measured EDCs varied from 20% to 70%, depending on flow conditions (ozone dosage being 0.5 gO3/gTOC). Biological tests, furthermore, displayed that the oxidation stage did not significantly reduce (only by 20%) the estrogenicity of the effluent and revealed the presence and/or formation of genotoxic compounds. These results highlight the importance of the application of an integrated (biological+chemical) analytical procedure for a global evaluation of treatment suitability; poor performances recorded in this study have been attributed to the presence of a significant industrial component in the influent wastewater.


Assuntos
Disruptores Endócrinos/análise , Disruptores Endócrinos/química , Recuperação e Remediação Ambiental/métodos , Ozônio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Ensaio Cometa , Estrogênios/química , Cromatografia Gasosa-Espectrometria de Massas , Itália , Testes para Micronúcleos , Mutagênicos/química , Extração em Fase Sólida
14.
Food Addit Contam ; 24(6): 561-72, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17487597

RESUMO

The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. The test has been used widely to study genotoxicity of many pesticides revealing that these compounds can induce chromosomal aberrations in root meristems of A. cepa. Pesticide residues can be present in fruit and vegetables and represent a risk for human health. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is well known. Several studies have shown that chronic exposure to low levels of pesticides can cause birth defects and that prenatal exposure is associated with carcinogenicity. This study evaluated the potential application of plant genotoxicity tests for monitoring mutagens in edible vegetables. The presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and eight types of grapes sampled from several markets in Campania, a region in Southern Italy, was monitored concurrently. The extracts were analysed for pesticides by gas chromatography and high-performance liquid chromatography, and for genotoxicity using two plant tests: the micronucleus test and the chromosomal aberration test in A. cepa roots. Thirty-three pesticides were detected, some of which are not approved. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests proved to be sensitive in monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave a much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.


Assuntos
Aberrações Cromossômicas/induzido quimicamente , Contaminação de Alimentos/análise , Cebolas/genética , Resíduos de Praguicidas/toxicidade , Testes para Micronúcleos/métodos , Cebolas/efeitos dos fármacos , Resíduos de Praguicidas/análise , Praguicidas , Extratos Vegetais/toxicidade , Verduras/química , Vitis/química
15.
Br J Dermatol ; 156(6): 1357-61, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17459045

RESUMO

Indeterminate cell histiocytosis (ICH) is a proliferation of indeterminate CD1a+, CD68+, S100+ and CD207- dermal dendritic cells. We describe a 39-year-old man who developed diffuse ICH and, 6 years later, acute myeloblastic leukaemia (AML). He was treated with cyclophosphamide, etoposide and vinblastine until 2003. In August 2004, he presented dyspnoea, hyperpyrexia and infiltration of the lung parenchyma, compatible with an AML invasion, and died after a course of induction chemotherapy. Cytomorphology and immunophenotype analyses suggested an ICH clonal evolution. The leukaemogenic role of etoposide is discussed. ICH has previously been reported in association with B-cell malignancy, but only one case has shown systemic progression.


Assuntos
Histiocitose/patologia , Leucemia Mieloide Aguda/patologia , Dermatopatias/patologia , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Evolução Fatal , Histiocitose/complicações , Histiocitose/tratamento farmacológico , Humanos , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/tratamento farmacológico , Masculino , Prevenção Secundária , Dermatopatias/etiologia
16.
Can J Physiol Pharmacol ; 64(5): 531-8, 1986 May.
Artigo em Inglês | MEDLINE | ID: mdl-3730938

RESUMO

A progressive conduction block leading to atrioventricular dissociation develops in perfused rabbit hearts within 20-30 min of exposure to Krebs containing 0.5 mM potassium (low K). A decrease in potassium permeability resulting in membrane depolarization (as seen in Purkinje fibers) could be responsible for the loss of excitability in nodal cells. We investigated the K dependence of the resting potential and the long-term effects of low K perfusion on the resting and action potentials of nodal cells in rabbit hearts. The resting potential of atrial, atrionodal, and nodal cells varied by 52, 41, and 34 mV per decade of change in Ko within the range of 5-50 mM K. Hyperpolarization of the resting membrane, a progressive decline in action potential amplitude, and a decrease in maximum rate of rise were observed in nodal fibers when exposed to low K. Loss of propagated activity occurred in the middle node within 20-30 min while the cells remained hyperpolarized. There was no evidence of electrogenic Na extrusion and it seems that the low nodal resting potential results from a high resting PNa/PK permeability ratio. The early decrease in rate of rise in low K probably reflects an increase in K-dependent outward currents, whereas the progressive deterioration and final loss of conducted electrical activity may result from an accumulation of internal Na and Ca overload produced by low K inhibition of the Na pump.


Assuntos
Nó Atrioventricular/fisiologia , Bloqueio Cardíaco , Sistema de Condução Cardíaco/fisiologia , Potássio/farmacologia , Potenciais de Ação/efeitos dos fármacos , Animais , Nó Atrioventricular/citologia , Nó Atrioventricular/efeitos dos fármacos , Sistema de Condução Cardíaco/efeitos dos fármacos , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Coelhos
17.
Can J Physiol Pharmacol ; 65(2): 246-51, 1987 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3567738

RESUMO

The diffusion and electrogenic components of the resting potential of hypoxic ventricular muscle were separated by inhibition of the sodium pump with 10(-4) M ouabain. The response to varying external K concentrations (Ko) was studied. Arterially perfused rabbit hearts were submitted to 60 min hypoxia in Krebs solution containing 5 mM K throughout or to different external K concentrations during the last 20 min of hypoxia. For K concentrations between 1.5 and 10 mM, hypoxia did not change the resting potential except for a slight hyperpolarization in 7.5 mM K. The diffusion component of the resting potential did not differ from the resting potential at Ko less than 5 mM. An electrogenic potential of -3 to -6 mV was detectable at Ko values between 5 and 10 mM. The internal K concentration, Ki, was estimated from extrapolations to zero potential of the relation resting potential vs. Ko in normoxic and hypoxic hearts. These experiments revealed a decline of Ki of 16 mM with hypoxia. The variation of the diffusion potential with external K was fitted by a PNa:PK ratio five times lower than in normoxia. It has been concluded that an increase in K permeability and the persistence of electrogenic Na extrusion during hypoxia of rather short duration prevent membrane depolarization despite the myocardial K loss.


Assuntos
Miocárdio/metabolismo , Oxigênio/farmacologia , Animais , Difusão , Eletrofisiologia , Coração/fisiologia , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Ouabaína/farmacologia , Potássio/metabolismo , Coelhos
18.
Circ Res ; 39(3): 326-36, 1976 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-954161

RESUMO

In the perfused rabbit heart,the upstroke of the transmembrane action potential of fibers of the atrioventricular (AV) node presents two distinct components. The first depends strongly on extracellular sdoium concentration, but the degree to which it is activated is influenced by extracellular calcium, as indicated by the correlation between its Vmax and [Ca2+]0. The second component depends on calcium and sodium concentrations and is blocked by Mn ions. An analysis comparing action potentials from atrial (A), atrionodal (AN), and nodal (N) fibers shows that the second component of the upstroke of the action potential contributes 12%, 27%, and 34% to the total depolarization. The results suggest that the upstroke of the nodal action potential results from the activation of two inward currents, as in ordinary cardiac fibers. We postulate that (1) the degree of steady state inactivation of gNa is larger in N than in A fibers because of the low resting potential of the former, and (2) the contribution of the second channel to the upstroke depends on the time course of the previous depolarization and the potential level at which this component is activated.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Nó Atrioventricular/fisiologia , Cálcio/farmacologia , Sistema de Condução Cardíaco/fisiologia , Sódio/farmacologia , Animais , Técnicas In Vitro , Manganês/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Coelhos
19.
Pathologica ; 86(5): 541-5, 1994 Oct.
Artigo em Italiano | MEDLINE | ID: mdl-7739882

RESUMO

The Authors describe a case of intranodal myofibroblastoma presenting in the submandibular region as a firm, indolent and freely mobile rounded nodule of about 3 cm. in diameter. The nature of this uncommon benign lesion is discussed. The observed histological features are partly different from the cases originally described. A proliferation of moderately pleomorphic spindle cells, which are vimentin and muscle specific actin positive, occupies a large part of a lymph node, sharply separated from the normal tissue. The so called "amianthoid fibres" are however absent and the inflammatory cells are almost exclusively eosinophils, mainly localized at the border between the lesion and the residual lymph node. Some spindle cells also show an unexplained positivity for the S-100 protein. In addition, extranodal extension of inflammation with few spindle cells is present. Such a complex picture has many features in common with the inflammatory pseudotumor of lymph node, another benign cause of lymphadenopathy. For this reason, the Authors suggest the possibility that myofibroblastoma is not a true neoplasm, but, together with the inflammatory pseudotumor, a peculiar type or a different stage of an abnormal lymph node reactivity.


Assuntos
Linfonodos/patologia , Neoplasias de Tecido Muscular/patologia , Humanos , Imuno-Histoquímica , Masculino , Mandíbula , Pessoa de Meia-Idade
20.
Am J Physiol ; 240(5): C183-8, 1981 May.
Artigo em Inglês | MEDLINE | ID: mdl-7235001

RESUMO

Intracellular chloride activity (aiCl) and membrane potential (Vm) were measured in rabbit papillary muscle under in vitro conditions. The cellular chloride concentration (Cli) was estimated from measurements of total water content, extracellular space, and total chloride concentration. The effects of therapeutic (10(-8) M) and toxic (10(-6) M) concentrations of ouabain on these parameters were tested. The chloride-sensitive microelectrodes were of the liquid-ion exchanger type. Selectivity for HCO-3 was taken into account in the calculation of aiCl. In 11 control experiments made with two different protocols aiCl was determined in subendocardial and in deeper cells. The mean membrane potentials were -78.7 and -78.0 mV and the mean cytoplasmic chloride activities were 17.5 and 17.7 mM, respectively. The chloride equilibrium potentials were -43.5 and -43.2 mV. These results indicated that chloride is not passively distributed in rabbit papillary muscle. Ouabain (10(-8) M) did not change Vm or aiCl. At a toxic concentration of ouabain, Vm fell to -68.0 mV in superficial cells and to -67.8 mV in deeper cells, but aiCl remained unchanged . These results suggested that under in vitro conditions intracellular chloride is distributed within more than one cellular compartment.


Assuntos
Cloretos/metabolismo , Miocárdio/metabolismo , Ouabaína/farmacologia , Animais , Compartimentos de Líquidos Corporais/efeitos dos fármacos , Espaço Extracelular/metabolismo , Técnicas In Vitro , Líquido Intracelular/metabolismo , Potenciais da Membrana , Microeletrodos , Músculos Papilares/metabolismo , Coelhos
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