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1.
Anaesthesist ; 65(5): 363-5, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27129535

RESUMO

We report a case of a 27-year-old anesthetist who acquired tuberculosis (TB) while performing general anesthesia in a renal transplant (RTX) patient who had donor-derived contagious TB. The anesthetist developed pleural TB 6 months after exposure. Contact investigations (CIs) did not include health care workers (HCWs) of the Department of Anesthesiology, thereby missing the opportunity for the early diagnosis and treatment of TB. Genomic fingerprinting revealed identical Mycobacterium tuberculosis (MT) isolates in the anesthetist and in the RTX patient. The recipient had acquired disseminated TB from the harvested renal graft. The donor (liver and kidneys), a 67-year-old immigrant, had died from brain death by cerebral herniation after a stroke. She had been treated for tuberculosis with a pneumectomy 40 years ago. Since that time, she had been suffering from latent tuberculous infection (TBI), but had been considered to have been cured.


Assuntos
Transmissão de Doença Infecciosa do Paciente para o Profissional , Transplante de Rim/efeitos adversos , Tuberculose Pulmonar/etiologia , Tuberculose Pulmonar/transmissão , Adulto , Idoso , Anestesistas , Antibióticos Antituberculose/uso terapêutico , Feminino , Humanos , Transplante de Fígado/efeitos adversos , Mycobacterium tuberculosis , Doadores de Tecidos , Tuberculose Pulmonar/terapia
2.
Infection ; 44(3): 365-70, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26498284

RESUMO

Because of global mobility and migration resulting in a growing diversity of the donor pool, the risk for donor-derived tuberculosis in solid organ transplant recipients becomes more and more relevant, even in countries with a low overall tuberculosis incidence. Here, we describe a case series of donor-derived tuberculosis in 2 of 3 solid organ transplant recipients and one medical staff member in Germany resulting in the death of one recipient. This case series highlights the relevance of this topic to clinicians. It advocates for a better communication between organ procurement organizations and transplant centers regarding donor information and transplant recipient outcome. Furthermore, it underpins the necessity for a standardized critical incident reporting system in the german transplant system to improve short- and long-term recipient's safety, health and survival.


Assuntos
Transplante de Órgãos/efeitos adversos , Doadores de Tecidos , Transplantados , Transplantes/microbiologia , Tuberculose , Idoso , Antituberculosos/administração & dosagem , Antituberculosos/uso terapêutico , Feminino , Pessoal de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia , Tuberculose/transmissão
3.
Biosystems ; 124: 26-38, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25063553

RESUMO

Systems biology has to increasingly cope with large- and multi-scale biological systems. Many successful in silico representations and simulations of various cellular modules proved mathematical modelling to be an important tool in gaining a solid understanding of biological phenomena. However, models spanning different functional layers (e.g. metabolism, signalling and gene regulation) are still scarce. Consequently, model integration methods capable of fusing different types of biological networks and various model formalisms become a key methodology to increase the scope of cellular processes covered by mathematical models. Here we propose a new integration approach to couple logical models of signalling or/and gene-regulatory networks with kinetic models of metabolic processes. The procedure ends up with an integrated dynamic model of both layers relying on differential equations. The feasibility of the approach is shown in an illustrative case study integrating a kinetic model of central metabolic pathways in hepatocytes with a Boolean logical network depicting the hormonally induced signal transduction and gene regulation events involved. In silico simulations demonstrate the integrated model to qualitatively describe the physiological switch-like behaviour of hepatocytes in response to nutritionally regulated changes in extracellular glucagon and insulin levels. A simulated failure mode scenario addressing insulin resistance furthermore illustrates the pharmacological potential of a model covering interactions between signalling, gene regulation and metabolism.


Assuntos
Redes Reguladoras de Genes , Modelos Biológicos , Transdução de Sinais , Calibragem , Cinética
4.
Phys Rev Lett ; 107(21): 216801, 2011 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-22181906

RESUMO

Low-temperature scanning tunneling microscopy and spectroscopy combined with first-principles simulations reveal a nondissociative physisorption of ferrocene molecules on a Cu(111) surface, giving rise to ordered molecular layers. At the interface, a 2D-like electronic band is found, which shows an identical dispersion as the Cu(111) Shockley surface-state band. Subsequent deposition of Cu atoms forms charged organometallic compounds that localize interface-state electrons.

5.
Vet Pathol ; 48(4): 875-84, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21147764

RESUMO

Liver tumors from a previous National Toxicology Program study were examined using global gene expression and mutation analysis to define the mechanisms of carcinogenesis in mice exposed to oxazepam. Five hepatocellular adenomas and 5 hepatocellular carcinomas from male B6C3F1 mice exposed to 5000 ppm oxazepam and 6 histologically normal liver samples from control animals were examined. One of the major findings in the study was upregulation of the Wnt/ß-catenin signaling pathway. Genes that activate ß-catenin, such as Sox4, were upregulated, whereas genes that inhibit Wnt signaling, such as APC and Crebbp, were downregulated. In addition, liver tumors from oxazepam-exposed mice displayed ß-catenin mutations and increased protein expression of glutamine synthetase, a downstream target in the Wnt signaling pathway. Another important finding in this study was the altered expression of oxidative stress-related genes, specifically increased expression of cytochrome p450 genes, including Cyp1a2 and Cyp2b10, and decreased expression of genes that protect against oxidative stress, such as Sod2 and Cat. Increased oxidative stress was confirmed by measuring isoprostane expression using mass spectrometry. Furthermore, global gene expression identified altered expression of genes that are associated with epigenetic mechanisms of cancer. There was decreased expression of genes that are hypermethylated in human liver cancer, including tumor suppressors APC and Pten. Oxazepam-induced tumors also exhibited decreased expression of genes involved in DNA methylation (Crebbp, Dnmt3b) and histone modification (Sirt1). These data suggest that formation of hepatocellular adenomas and carcinomas in oxazepam-exposed mice involves alteration of the Wnt signaling pathway, oxidative stress, and potential epigenetic alterations.


Assuntos
Carcinógenos/toxicidade , Epigênese Genética/fisiologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias Hepáticas Experimentais/induzido quimicamente , Oxazepam/toxicidade , Animais , Feminino , Genoma , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Mutação , Estresse Oxidativo , Reação em Cadeia da Polimerase/métodos , Análise Serial de Proteínas , Reprodutibilidade dos Testes , Transdução de Sinais , Proteínas Wnt/genética , Proteínas Wnt/metabolismo
6.
Toxicology ; 257(1-2): 33-9, 2009 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-19114085

RESUMO

Cresols, monomethyl derivatives of phenol, are high production chemicals with potential for human exposure. The three isomeric forms of cresol are used individually or in mixtures as disinfectants, preservatives, and solvents or as intermediates in the production of antioxidants, fragrances, herbicides, insecticides, dyes, and explosives. Carcinogenesis studies were conducted in groups of 50 male F344/N rats and 50 female B6C3F1 mice exposed to a 60:40 mixture of m- and p-cresols (m-/p-cresol) in feed. Rats and mice were fed diets containing 0, 1500, 5000, or 15,000 ppm and 0, 1000, 3000, or 10,000 ppm, respectively. Survival of each exposed group was similar to that of their respective control group. Mean body weight gains were depressed in rats exposed to 15,000 ppm and in mice exposed to 3000 ppm and higher. A decrease of 25% over that of controls for the final mean body weight in mice exposed to 10,000 ppm appeared to be associated with lack of palatability of the feed. A marginally increased incidence of renal tubule adenoma was observed in the 15,000-ppm-exposed rats. The increased incidence was not statistically significant, but did exceed the range of historical controls. No increased incidence of hyperplasia of the renal tubules was observed; however, a significantly increased incidence of hyperplasia of the transitional epithelium associated with an increased incidence of nephropathy was observed at the high exposure concentration. The only significantly increased incidence of a neoplastic lesion related to cresol exposure observed in these studies was that of squamous cell papilloma in the forestomach of 10,000-ppm-exposed mice. A definitive association with irritation at the site-of-contact could not be made because of limited evidence of injury to the gastric mucosa at the time of necropsy. However, given the minimal chemical-related neoplastic response in these studies, it was concluded that there was no clear evidence of carcinogenicity in male rats or female mice exposed to the cresol mixture.


Assuntos
Testes de Carcinogenicidade , Carcinógenos/toxicidade , Cresóis/toxicidade , Neoplasias Renais/patologia , Neoplasias/induzido quimicamente , Adenoma/induzido quimicamente , Adenoma/patologia , Animais , Peso Corporal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/patologia , Neoplasias Renais/induzido quimicamente , Túbulos Renais/efeitos dos fármacos , Túbulos Renais/patologia , Masculino , Camundongos , Neoplasias/patologia , Papiloma/induzido quimicamente , Papiloma/patologia , Ratos , Ratos Endogâmicos F344 , Neoplasias Gástricas/induzido quimicamente , Neoplasias Gástricas/patologia , Fatores de Tempo
7.
Phys Rev Lett ; 101(11): 116602, 2008 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-18851307

RESUMO

Low-temperature spin-polarized scanning tunneling microscopy is employed to study spin transport across single cobalt-phthalocyanine molecules adsorbed on well-characterized magnetic nanoleads. A spin-polarized electronic resonance is identified over the center of the molecule and exploited to spatially resolve stationary spin states. These states reflect two molecular spin orientations and, as established by density functional calculations, originate from a ferromagnetic molecule-lead exchange interaction.

8.
HIV Med ; 8(1): 28-31, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17305929

RESUMO

BACKGROUND: Standard two-step HIV testing is limited by poor return-for-results rates and misses high-risk individuals who do not access conventional testing facilities. METHODS: We describe a community-based rapid HIV testing programme in which homeless and marginally housed adults recruited from shelters, free meal programmes and single room occupancy hotels in San Francisco received OraQuick Rapid HIV-1 Antibody testing (OraSure Technologies, Bethlehem, PA, USA). RESULTS: Over 8 months, 1614 adults were invited to participate and 1213 (75.2%) underwent testing. HIV seroprevalence was 15.4% (187 of 1213 individuals) overall and 3.5% (37 of 1063) amongst high-risk individuals reporting no previous testing, a prior negative test, or previous testing without result disclosure. All 1213 participants received their results. Of 30 newly diagnosed persons who received confirmatory results, 26 (86.7%) reported at least one contact with a primary healthcare provider in the 6 months following diagnosis. CONCLUSIONS: We conclude that community-based rapid testing is feasible, acceptable and effective based on the numbers of high-risk persons tested over a short period, the participation rate, the prevalence of new infection, the rate of result disclosure, and the proportion linked to care.


Assuntos
Infecções por HIV , Soroprevalência de HIV , Programas de Rastreamento/métodos , Adolescente , Adulto , Serviços de Saúde Comunitária , Feminino , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Acessibilidade aos Serviços de Saúde , Pessoas Mal Alojadas , Humanos , Masculino , Pessoa de Meia-Idade , Características de Residência , São Francisco/epidemiologia , Saúde da População Urbana , Serviços Urbanos de Saúde
9.
Food Chem Toxicol ; 45(5): 843-51, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17187913

RESUMO

Benzophenone, an aryl ketone, is used primarily as a photoinitiator and fragrance enhancer. Groups of 50 male and 50 female F344 rats and B6C3 F1 mice were fed diets containing 0, 312, 625, and 1250 ppm benzophenone for 105 weeks. Survival of males exposed to 1250 ppm benzophenone was significantly less than that of controls. There was a positive trend in the incidence of renal tubule adenoma in male rats; these neoplasms were accompanied by significantly increased incidences of renal tubule hyperplasia. Increased incidences of mononuclear cell leukemia were observed in male rats exposed to 312 or 625 ppm benzophenone and in female rats exposed to 625 ppm benzophenone. Liver lesions observed included significantly increased incidences of hepatocytic centrilobular hypertrophy in all exposed groups of rats. In mice, survival of all exposed groups was generally similar to that of the control groups. In male mice, there were significantly increased incidences of hepatocellular adenoma in the 625 and 1250 ppm groups. In female mice, the incidences of hepatocellular adenoma in the 625 and 1250 ppm groups were higher than expected after adjusting for the lower body weights in these groups. The incidences of kidney nephropathy in exposed groups of female mice, as well as the severity of nephropathy in exposed groups of males, were significantly increased. The incidences of metaplasia of the olfactory epithelium were significantly increased in 1250 ppm mice. Rare histiocytic sarcomas were observed in female rats and mice in the 625 and 1250 ppm groups. Under the conditions of these 2-year studies, there was some evidence of carcinogenic activity of benzophenone in male F344/N rats based on increased incidences of renal tubule adenoma. There was equivocal evidence of carcinogenic activity of benzophenone in female F344/N rats based on the marginal increased incidences of mononuclear cell leukemia and histiocytic sarcoma. There was some evidence of carcinogenic activity of benzophenone in male B6C3F(1) mice based on increased incidences of hepatocellular neoplasms, primarily adenoma. There was some evidence of carcinogenic activity of benzophenone in female B6C3F(1) mice based on increased incidences of histiocytic sarcoma; the incidences of hepatocellular adenoma in female B6C3F(1) mice may have been related to benzophenone exposure.


Assuntos
Benzofenonas/toxicidade , Testes de Carcinogenicidade/métodos , Neoplasias Experimentais/induzido quimicamente , Fármacos Fotossensibilizantes/toxicidade , Adenoma/induzido quimicamente , Adenoma/patologia , Animais , Relação Dose-Resposta a Droga , Feminino , Transtornos Histiocíticos Malignos/induzido quimicamente , Transtornos Histiocíticos Malignos/patologia , Neoplasias Renais/induzido quimicamente , Neoplasias Renais/patologia , Leucemia/induzido quimicamente , Leucemia/patologia , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Neoplasias Experimentais/patologia , Ratos , Ratos Endogâmicos F344 , Sarcoma/induzido quimicamente , Sarcoma/patologia , Fatores Sexuais
10.
Phys Rev Lett ; 99(24): 246102, 2007 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-18233461

RESUMO

Low-temperature scanning tunneling spectroscopy over Co nanoislands on Cu(111) showed that the surface states of the islands vary with their size. Occupied states exhibit a sizable downward energy shift as the island size decreases. The position of the occupied states also significantly changes across the islands. Atomic-scale simulations and ab initio calculations demonstrate that the driving force for the observed shift is related to size-dependent mesoscopic relaxations in the nanoislands.

11.
Food Chem Toxicol ; 42(11): 1757-68, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15350673

RESUMO

trans-Cinnamaldehyde is a widely used natural ingredient that is added to foods and cosmetics as a flavoring and fragrance agent. Male and female F344/N rats and B6C3F(1) mice were exposed to microencapsulated trans-cinnamaldehyde in the feed for three months or two years. All studies included untreated and vehicle control groups. In the three-month studies, rats and mice were given diets containing 4100, 8200, 16,500, or 33,000 ppm trans-cinnamaldehyde. In rats, feed consumption was reduced in all exposed groups. In mice, feed consumption was reduced in the highest dose groups. Body weights of all treated males were less than controls. Body weights were reduced in female rats exposed to 16,500 or 33,000 ppm and female mice exposed to 8200 ppm or greater. All rats survived to the end of the study but some male mice in the highest dose groups died due to inanition from unpalatability of the dosed feed. The incidence of squamous epithelial hyperplasia of the forestomach was significantly increased in rats exposed to 8200 ppm or greater and female mice exposed to 33,000 ppm. In mice, the incidence of olfactory epithelial degeneration of the nasal cavity was significantly increased in males and females exposed to 16,500 ppm and females exposed to 33,000 ppm. In the two-year studies, rats and mice were exposed to 1000, 2100, or 4100 ppm trans-cinnamaldehyde. Body weights were reduced in mice exposed to 2100 ppm and in rats and mice exposed to 4100 ppm. In rats, hippuric acid excretion was dose proportional indicating that absorption, metabolism, and excretion were not saturated. No neoplasms were attributed to trans-cinnamaldehyde in rats or mice. Squamous cell papillomas and carcinomas of the forestomach were observed in male and female mice but the incidences were within the NTP historical control range and were not considered to be related to trans-cinnamaldehyde exposure.


Assuntos
Acroleína/análogos & derivados , Acroleína/toxicidade , Carcinógenos/toxicidade , Aromatizantes/toxicidade , Estômago/efeitos dos fármacos , Administração Oral , Animais , Peso Corporal/efeitos dos fármacos , Testes de Carcinogenicidade , Relação Dose-Resposta a Droga , Composição de Medicamentos , Feminino , Estudos Longitudinais , Masculino , Camundongos , Camundongos Endogâmicos , Distribuição Aleatória , Ratos , Ratos Endogâmicos F344 , Estômago/patologia , Análise de Sobrevida
12.
Toxicol Sci ; 74(2): 287-96, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12773761

RESUMO

Vanadium pentoxide (V2O5) is a slightly soluble compound found in airborne particle emissions from metallurgical works and oil and coal burning. Because the carcinogenic potential of V2O5 was not known, F344/N rats and B6C3F1 mice (N=50/sex/species) were exposed to V2O5 at concentrations of 0, 0.5 (rats only), 1, 2, or 4 (mice only) mg/m3, by whole-body inhalation for 2 years. The survival and body weights of rats were minimally affected by exposure to V2O5. The survival and body weights of male mice exposed to 4 mg/m3 and body weights of all exposed groups of female mice were lower than the controls. Alveolar/bronchiolar (A/B) neoplasms occurred in male rats exposed to 0.5 and 2 mg/m3 at incidences exceeding the National Toxicology Program (NTP) historical control ranges. A marginal increase in A/B neoplasms was also observed in female rats exposed to 0.5 mg/m3. Increases in chronic inflammation, interstitial fibrosis, and alveolar and bronchiolar hyperplasia/metaplasia and squamous metaplasia were observed in exposed male and female rats. A/B neoplasms were significantly increased in all groups of exposed mice. As with rats, increases in chronic inflammation, interstitial fibrosis, and alveolar and bronchiolar epithelial hyperplasia were observed in mice exposed to V2O5. Thus, V2O5 exposure was a pulmonary carcinogen in male rats and male and female mice. The marginal tumor response in the lungs of female rats could not be attributed conclusively to exposure to V2O5. These responses were noted at and slightly above the OSHA permissible occupational exposure limit of 0.5 mg/m3 (dust) (National Institute for Occupational Safety and Health, NIOSH Pocket Guide to Chemical Hazards, U.S. Department of Health and Human Services, Washington, DC, 1997, p. 328).


Assuntos
Adenoma/induzido quimicamente , Carcinógenos/toxicidade , Carcinoma/induzido quimicamente , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Experimentais/induzido quimicamente , Compostos de Vanádio/toxicidade , Adenoma/patologia , Administração por Inalação , Animais , Peso Corporal/efeitos dos fármacos , Testes de Carcinogenicidade , Carcinógenos/administração & dosagem , Carcinoma/patologia , Feminino , Longevidade/efeitos dos fármacos , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Ratos , Ratos Endogâmicos F344 , Sistema Respiratório/efeitos dos fármacos , Sistema Respiratório/patologia , Compostos de Vanádio/administração & dosagem
14.
Toxicol Sci ; 71(2): 198-206, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12563105

RESUMO

Citral, a widely used natural ingredient, is added to foods and cosmetics as a flavoring and fragrance agent. Male and female F344/N rats and B6C3F1 mice were exposed to microencapsulated citral in the feed for 14 weeks or two years. All studies included untreated and vehicle control groups. In the 14-week studies, rats and mice were given diets containing 3,900, 7,800, 15,600, or 31,300 ppm citral. In rats, food consumption was reduced in the two highest dose groups. In mice an apparent increase in food consumption was observed, but was due to mice scattering the feed. Body weights of all treated animals were less than controls. All rats and four male mice were killed moribund in the high dose groups. In rats, forestomach and kidney lesions were observed. At the higher doses, lesions observed in the bone marrow, testes, and thymus in rats and in the ovary in mice were considered related to inanition and resultant moribundity. In the two-year studies, rats were exposed to 1,000, 2,000, or 4,000 ppm citral. Body weights were reduced in the 4,000 ppm rats. Mice were exposed to 500, 1,000, or 2,000 ppm citral. Body weights in the 1,000 and 2,000 ppm groups were reduced. No neoplasms were attributed to citral in rats or mice. Malignant lymphoma occurred with a positive trend and was significantly greater than controls in female mice in the 2,000 ppm group. However, the incidences were within the NTP historical control range and could not be clearly related to citral administration.


Assuntos
Testes de Carcinogenicidade , Carcinógenos/toxicidade , Aromatizantes/toxicidade , Monoterpenos/toxicidade , Neoplasias Experimentais/etiologia , Monoterpenos Acíclicos , Administração Oral , Animais , Peso Corporal/efeitos dos fármacos , Carcinógenos/administração & dosagem , Dieta , Relação Dose-Resposta a Droga , Composição de Medicamentos , Feminino , Aromatizantes/administração & dosagem , Rim/efeitos dos fármacos , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Monoterpenos/administração & dosagem , Neoplasias Experimentais/patologia , Ratos , Ratos Endogâmicos F344 , Estômago/efeitos dos fármacos , Estômago/patologia
15.
Tree Physiol ; 22(9): 613-23, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12069917

RESUMO

To determine the relationship between phloem transport and changes in phloem water content, we measured temporal and spatial variations in water content and sucrose, glucose and fructose concentrations in phloem samples and phloem exudates of 70- and 30-year-old Norway spruce trees (Picea abies (L.) Karst.). Large temporal and spatial variations in phloem water content (1.4-2.6 mg mg(dw)(-1)) and phloem total sugar concentration (31-70 mg g(dw)(-1)) paralleled each other (r(2) = 0.83, P < 0.0001 for the temporal profile and r(2) = 0.96, P < 0.008 for the spatial profile), indicating that phloem water content depends on the total amount of sugar to be transferred. Changes in phloem water content were unrelated to changes in bark thickness. Maximum changes in phloem water content calculated from dendrometer readings were only 8-11% of the maximum measured changes in phloem water content, indicating that reversible changes in bark thickness did not reflect changes in internal water relations. We also studied the relationship between xylem sap velocity and changes in bark thickness in 70-year-old trees during summer 1999 and winter 1999-2000. Sap flow occurred sporadically throughout the winter, but there was no relationship between bark shrinkage or swelling and sap velocity. In winter, mean daily xylem sap velocity was significantly correlated with mean daily vapor pressure deficit and air temperature (P < 0.0001, in both cases). Changes in bark thickness corresponded with both short- and long-term changes in relative humidity, in both winter and summer. Under controlled conditions at > 0 degrees C, changes in relative humidity alone caused changes in thickness of boiled bark samples. Because living bark of Norway spruce trees contains large areas with crushed and dead sieve cell zones-up to 24% of the bark is air-filled space-we suggest that this space can compensate for volume changes in living phloem cells independently of total tissue water content. We conclude that changes in bark thickness are not indicative of changes in either phloem water capacitance or xylem sap flow.


Assuntos
Picea/fisiologia , Casca de Planta/fisiologia , Árvores/fisiologia , Espaço Extracelular/fisiologia , Frutose/análise , Glucose/análise , Picea/química , Casca de Planta/anatomia & histologia , Casca de Planta/química , Caules de Planta/química , Caules de Planta/fisiologia , Transpiração Vegetal/fisiologia , Estações do Ano , Sacarose/análise , Árvores/química , Água/análise , Água/fisiologia
16.
Toxicol Pathol ; 29 Suppl: 60-80, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11695563

RESUMO

In a Government/Industry/Academic partnership to evaluate alternative approaches to carcinogenicity testing, 21 pharmaceutical agents representing a variety of chemical and pharmacological classes and possessing known human and or rodent carcinogenic potential were selected for study in several rodent models. The studies from this partnership project, coordinated by the International Life Sciences Institute, provide additional data to better understand the models' limitations and sensitivity in identifying carcinogens. The results of these alternative model studies were reviewed by members of Assay Working Groups (AWG) composed of scientists from government and industry with expertise in toxicology, genetics, statistics, and pathology. The Tg.AC genetically manipulated mouse was one of the models selected for this project based on previous studies indicating that Tg.AC mice seem to respond to topical application of either mutagenic or nonmutagenic carcinogens with papilloma formation at the site of application. This communication describes the results and AWG interpretations of studies conducted on 14 chemicals administered by the topical and oral (gavage and/or diet) routes to Tg.AC genetically manipulated mice. Cyclosporin A, an immunosuppresant human carcinogen, ethinyl estradiol and diethylstilbestrol (human hormone carcinogens) and clofibrate, an hepatocarcinogenic peroxisome proliferator in rodents, were considered clearly positive in the topical studies. In the oral studies, ethinyl estradiol and diethylstilbestrol were negative, cyclosporin was considered equivocal, and results were not available for the clofibrate study. Of the 3 genotoxic human carcinogens (phenacetin, melphalan, and cyclophosphamide), phenacetin was negative by both the topical and oral routes. Melphalan and cyclophosphamide are, respectively, direct and indirect DNA alkylating agents and topical administration of both caused equivocal responses. With the exception of clofibrate, Tg.AC mice did not exhibit tumor responses to the rodent carcinogens that were putative human noncarcinogens, (di(2-ethylhexyl) phthalate, methapyraline HCl, phenobarbital Na, reserpine, sulfamethoxazole or WY-14643, or the nongenotoxic, noncarcinogen, sulfisoxazole) regardless of route of administration. Based on the observed responses in these studies, it was concluded by the AWG that the Tg.AC model was not overly sensitive and possesses utility as an adjunct to the battery of toxicity studies used to establish human carcinogenic risk.


Assuntos
Testes de Carcinogenicidade/métodos , Carcinógenos/toxicidade , Genes ras , Papiloma/induzido quimicamente , Neoplasias Cutâneas/induzido quimicamente , Alternativas aos Testes com Animais , Animais , Modelos Animais de Doenças , Feminino , Genótipo , Masculino , Camundongos , Camundongos Transgênicos , Papiloma/genética , Papiloma/patologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia
17.
J Synchrotron Radiat ; 8(Pt 2): 663-5, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11512888

RESUMO

The local structures of Am, Nd and Er-Benzimidazole (Biz) in solution were determined by EXAFS. The BIZ molecule coordinated to Am and Nd through two nitrogen atoms in a bidentate fashion. Two nitrogen atoms of BIZ ligated to Am and Nd with the bond distances R(Am-n) N=2.63A and R(Nd-N) = 2.65 A, respectively. The total coordination number of the Am BIZ complexes (at a molar ratio of metal ion to ligand of 1:20) was approximately 10 but that of Nd BIZ complex was approximately 9.

18.
Food Chem Toxicol ; 39(4): 303-16, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11295478

RESUMO

Methyleugenol, a food flavor and fragrance agent, was tested for toxicity in male and female F344/N rats and B6C3F1 mice. Groups of 10 males and 10 females per sex per species were administered 0, 10, 30, 100, 300 or 1000 mg methyleugenol/kg body weight in 0.5% aqueous methylcellulose by gavage, 5 days per week for 14 weeks. Additional groups of rats and mice of each sex were dosed similarly and used for hematology and clinical chemistry studies. Groups of 10 male and 10 female rats and mice received the vehicle by gavage on the same dosing schedule and served as vehicle controls. For serum gastrin, gastric pH and cell proliferation studies groups of 10 female rats were given 0, 37, 75 or 150 mg/kg, once daily 5 days per week for 30 or 90 days or 300 or 1000 mg/kg for 30 days; male mice were given 0, 9, 18.5, 37, 75, 150 or 300 mg/kg for 30 or 90 days. For the gastrin, pH and cell proliferation studies, groups of 10 female rats and 10 male mice were given the vehicle for 30 or 90 days and served as controls. Methyleugenol administration to rats induced erythrocyte microcytosis and thrombocytosis in male and female rats. It also caused an increase in serum alanine aminotransferase and sorbitol dehydrogenase activities and bile acid concentration, suggesting hepatocellular injury, cholestasis or altered hepatic function. Additionally, methyleugenol induced hypoproteinemia and hypoalbuminemia, evidenced by decreased total protein and albumin concentrations in both male and female rats, suggesting in inefficiency of dietary protein utilization due to methyleugenol-induced toxic effects on the liver and glandular stomach of rats and mice. The increase in gastrin and gastric pH of rats and mice given methyleugenol suggests that gastrin feedback was impaired and resulted in conditions not conducive to protein digestion. In rats, methyleugenol caused an increase in the incidences of hepatocyte cytologic alteration, cytomegaly, Kupffer cell pigmentation, mixed foci of cellular alteration and bile duct hyperplasia of the liver and atrophy and chronic inflammation of the mucosa of the glandular stomach. In mice, it caused an increase in the incidence of cytologic alteration, necrosis, bile duct hyperplasia and subacute inflammation of the liver and atrophy, degeneration, necrosis, edema, mitotic alteration, and cystic glands of the fundic region of the glandular stomach. The increased incidences of adrenal gland cortical hypertrophy and/or cytoplasmic alteration in the submandibular salivary glands, adrenal glands, testis and uterus of rats were considered secondary to the chemical-related effects observed in the liver and glandular stomach. Based on mortality, body weight gain, clinical chemistry and gross and microscopic evaluation of tissues of rats and mice, the no-observed-effect level (NOEL) of methyleugenol for both species was estimated at 10 mg/kg.


Assuntos
Eugenol/toxicidade , Mucosa Gástrica/efeitos dos fármacos , Fígado/efeitos dos fármacos , Mutagênicos/toxicidade , Alanina Transaminase/sangue , Animais , Peso Corporal , Divisão Celular/efeitos dos fármacos , Testes Imunológicos de Citotoxicidade , Relação Dose-Resposta a Droga , Eritrócitos , Eugenol/análogos & derivados , Feminino , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Gastrinas/sangue , Concentração de Íons de Hidrogênio , L-Iditol 2-Desidrogenase/metabolismo , Fígado/enzimologia , Fígado/patologia , Masculino , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Especificidade de Órgãos , Ratos , Ratos Endogâmicos F344 , Trombocitose
19.
Toxicol Sci ; 60(1): 28-37, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11222870

RESUMO

p,p'-Dichlorodiphenyl sulfone (DDS) is used as a starting material in the production of polysulfones and polyethersufones, a family of thermoplastics. DDS was studied because of its high production volume and use. In toxicology studies, 10 Fischer 344 rats and 10 B6C3F1 mice/sex/group were fed diets containing 0, 30, 100, 300, 1,000 or 3,000 ppm DDS for 14 weeks. All animals survived until the end of the studies. Mean body weights of groups exposed to 300 ppm or greater were significantly decreased. Liver and kidney in rats and liver in mice were the major target organs of DDS toxicity. Dose-related increases in liver weights and incidences of centrilobular hepatocyte hypertrophy were observed in DDS-exposed groups. Nephropathy was seen in male and female rats only at and above 300 ppm. Neurotoxicity evaluations were negative in DDS-treated animals. Clinical chemistry and hematology parameters were minimally affected. In the 2-year toxicity and carcinogenicity studies, 50 rats and 50 mice/sex/group were fed diets containing 0, 10 (male rats), 30, 100, or 300 ppm DDS for 104 to 105 weeks. Survival of exposed groups was not affected. There were no clinical signs of toxicity related to DDS exposure. Final mean body weights were 2-17% lower in DDS-treated groups. Liver was the only target organ of DDS-induced toxicity. The incidence of centrilobular hepatocyte hypertrophy in mice and rats, and the incidence of bile duct hyperplasia and centrilobular degeneration in female rats was significantly greater than in controls. A no-observed-adverse-effect level (NOAEL) of 30 ppm DDS in the diet (1.5 mg/kg body weight) was established for rats. DDS was not carcinogenic in these studies.


Assuntos
Carcinógenos/toxicidade , Sulfonas/toxicidade , Animais , Peso Corporal/efeitos dos fármacos , Testes de Carcinogenicidade , Química Clínica , Dieta , Relação Dose-Resposta a Droga , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Testes Hematológicos , Rim/efeitos dos fármacos , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Exame Neurológico , Nível de Efeito Adverso não Observado , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Endogâmicos F344 , Sulfonas/administração & dosagem
20.
Cancer Pract ; 9(2): 66-70, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11879281

RESUMO

PURPOSE: A program evaluation was conducted to explore the potential effects of a 90-minute problem-solving education session for persons with advanced cancer and their families. DESCRIPTION OF PROGRAM: Patients with advanced cancer and their families, who were visiting a tertiary-care outpatient setting, were invited to attend a 90-minute individualized educational session that taught basic problem-solving principles using a cognitive-behavioral framework. Pre-education and posteducation data were collected about the confidence of participants in providing care, their feelings about being informed about resources, and their perceptions of their problem-solving ability. RESULTS: At baseline, most participants reported low confidence about their ability to provide cancer care and felt uninformed about community resources, but they viewed themselves as moderate-to-good problem solvers. Forty-two educational sessions were delivered to 49 caregivers and 40 patients. Two months later, participants reported feeling more informed about community resources and achieved higher posteducation scores for problem-solving ability. More caregivers than patients reported that reading The Home Care Guide for Cancer made a great deal of difference in their approach to home care. CLINICAL IMPLICATIONS: Most educational sessions for families affected by cancer focus on delivering information, not on building skills. These findings suggest that a one-on-one educational session that teaches problem-solving skills can be successfully delivered in a busy clinic setting. Family caregivers are especially likely to benefit from this program.


Assuntos
Cuidadores/educação , Neoplasias/terapia , Educação de Pacientes como Assunto/organização & administração , Resolução de Problemas , Humanos , Avaliação de Programas e Projetos de Saúde , Estados Unidos
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