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1.
Ultrasound Int Open ; 2(1): E13-8, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27689161

RESUMO

PURPOSE: The purpose of this study was to investigate the consistency between different Doppler ultrasound (DU) modes as well as the intra- and inter-observer reliability of investigators with different experience level in assessing intratendinous blood flow (IBF) in Achilles tendinopathy patients. MATERIAL AND METHODS: 18 participants (36 Achilles tendons, AT) with Achilles tendinopathy (24 AT) were examined with power Doppler ultrasound (PDU), colour Doppler ultrasound (CDU) and "Advanced Dynamic Flow" (ADF) (Toshiba Xario SSA-660 A; 14MHz transducer) by 2 investigators (experienced, EI; inexperienced, II) in a test-retest design (M1/M2). A modified Öhberg score was used to quantify IBF. Data was analysed descriptively (absolute and relative). Consistency of the 3 modes was presented by Kendall's Coefficient of Concordance (Kendall's W). Intra- and inter-observer reliability were calculated by use of Kendall's tau b correlation coefficient. RESULTS: IBF was detected in 79-92% of symptomatic AT and in 33-50% of contralateral asymptomatic AT. Comparing the 3 modes, Kendall's W ranged from 0.97-0.98. Analysis of intra-observer reliability resulted in Kendall's tau 0.90-0.92 for EI and 0.84-0.87 for II. Inter-observer reliability resulted in Kendall's tau 0.64-0.69 in M1 and 0.68-0.70 in M2. CONCLUSION: The very good consistency between PDU, CDU and ADF indicates a comparable applicability for assessing IBF in ATs. Intra-observer reliability was high for both investigators, independent of experience. The moderate inter-observer reliability reflects the challenge in sonographic detection of intratendinous blood flow (IBF) amount.

2.
Clin Rheumatol ; 33(9): 1255-62, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24824913

RESUMO

The objectives of this study are to evaluate a new semi-quantitative (0-5) musculoskeletal ultrasound (US) erosion score in patients with rheumatoid arthritis (RA) and to prove its usefulness in the detection of disease activity and success of therapy. Thirty-eight patients with RA (mean disease duration 10.1 ± 11.9 years) were enrolled. Start or change of therapy (DMARD/biologics) was an inclusion criterion. DAS28, laboratory (ESR and CRP) and US data were evaluated before new therapy initiation and after 1, 3, 6 and 12 months. Thirteen joints of the clinically more affected hand and forefoot (wrist and MCP, PIP, MTP joints 2-5) were analyzed for synovitis in grayscale (GS) and power Doppler (PD) US, tenosynovitis/paratenonitis in GS/PDUS (wrist, MCP level) and for erosions. Erosions were analyzed by a new semi-quantitative score (grade 0, no erosion; grade 1, <1 mm, grade 2, 1 to <2 mm; grade 3, 2 to ≤3 mm; grade 4, >3 mm; grade 5, multiple bone erosions). After 12 months, DAS28 decreased from 4.5 to 3.4 (p < 0.001), the synovitis score in GSUS from 26.3 to 12.8 (p = 0.001) and the synovitis score in PDUS from 10.6 to 4.1 (p < 0.001). The erosion score decreased from 21.5 to 18.1 (p = 0.046). There were longitudinal significant correlations between the new erosion score and both the DAS28 (r = 0.368; p = 0.025) and the synovitis score in PDUS (r = 0.365; p = 0.026) over a 1-year follow-up period. The new erosion score might be a useful tool for the evaluation of erosive changes by US in RA patients. In the course of DMARD and biologic therapy, it was responsive under 1-year follow-up examination.


Assuntos
Artrite Reumatoide/diagnóstico por imagem , Articulação da Mão/diagnóstico por imagem , Sinovite/diagnóstico por imagem , Adulto , Idoso , Antirreumáticos/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Resultado do Tratamento , Ultrassonografia
3.
Arthritis Care Res (Hoboken) ; 66(2): 204-16, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23925935

RESUMO

OBJECTIVE: To assess the value of gray-scale (GS) and power Doppler (PD) ultrasound (US) in detecting inflammatory/destructive changes and for prediction of necessity of re-therapy with rituximab (RTX) in patients with rheumatoid arthritis (RA) over 1 year of followup. METHODS: GSUS and PDUS were performed to assess synovitis, tenosynovitis, and erosions on the clinically dominant hand and forefoot of 20 patients with RA before and after therapy with RTX. US parameters were compared with clinical (Disease Activity Score in 28 joints, tender/swollen joint counts, and patients' visual analog scale of disease activity) and laboratory parameters (C-reactive protein level and erythrocyte sedimentation rate). Results were compared for patients with and without re-therapy with RTX. RESULTS: Significant decreases in clinical and laboratory parameters were observed after 6 and 12 months. US synovitis scores significantly decreased after 6 and 12 months (P < 0.05 for each). Regarding patients who received re-therapy between 6 and 9 months after the start of therapy (n = 9), a fair therapy response was still detectable before re-therapy. In these patients, PD-positive synovitis was the only parameter that increased up to the 6-month examination. All patients negative for rheumatoid factor and anti-cyclic citrullinated peptide (n = 4) were in the group of patients receiving a second course of treatment. Seropositive patients showed a better response to treatment with less need for re-therapy. CONCLUSION: Response to therapy was measurable by clinical and laboratory parameters as well as by US. Since PDUS was able to detect the onset of disease activity before worsening of clinical symptoms occurred, PDUS is most helpful in evaluating disease activity and making earlier therapy decisions.


Assuntos
Anticorpos Monoclonais Murinos/administração & dosagem , Antirreumáticos/administração & dosagem , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/tratamento farmacológico , Articulações do Pé/efeitos dos fármacos , Articulações do Pé/diagnóstico por imagem , Articulação da Mão/efeitos dos fármacos , Articulação da Mão/diagnóstico por imagem , Ultrassonografia Doppler , Adulto , Idoso , Artrite Reumatoide/sangue , Biomarcadores/sangue , Sedimentação Sanguínea , Proteína C-Reativa/metabolismo , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Rituximab , Índice de Gravidade de Doença , Inquéritos e Questionários , Sinovite/diagnóstico por imagem , Sinovite/tratamento farmacológico , Tenossinovite/diagnóstico por imagem , Tenossinovite/tratamento farmacológico , Fatores de Tempo , Resultado do Tratamento
4.
Acta Biomater ; 8(3): 1239-47, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21925622

RESUMO

There is increasing demand for automated cell reprogramming in the fields of cell biology, biotechnology and the biomedical sciences. Microfluidic-based platforms that provide unattended manipulation of adherent cells promise to be an appropriate basis for cell manipulation. In this study we developed a magnetically driven cell carrier to serve as a vehicle within an in vitro environment. To elucidate the impact of the carrier on cells, biocompatibility was estimated using the human adenocarcinoma cell line Caco-2. Besides evaluation of the quality of the magnetic carriers by field emission scanning electron microscopy, the rate of adherence, proliferation and differentiation of Caco-2 cells grown on the carriers was quantified. Moreover, the morphology of the cells was monitored by immunofluorescent staining. Early generations of the cell carrier suffered from release of cytotoxic nickel from the magnetic cushion. Biocompatibility was achieved by complete encapsulation of the nickel bulk within galvanic gold. The insulation process had to be developed stepwise and was controlled by parallel monitoring of the cell viability. The final carrier generation proved to be a proper support for cell manipulation, allowing proliferation of Caco-2 cells equal to that on glass or polystyrene as a reference for up to 10 days. Functional differentiation was enhanced by more than 30% compared with the reference. A flat, ferromagnetic and fully biocompatible carrier for cell manipulation was developed for application in microfluidic systems. Beyond that, this study offers advice for the development of magnetic cell carriers and the estimation of their biocompatibility.


Assuntos
Ouro/química , Magnetismo , Imãs , Teste de Materiais , Técnicas Analíticas Microfluídicas , Níquel/química , Células CACO-2 , Adesão Celular , Proliferação de Células , Humanos
5.
Br J Cancer ; 98(12): 1959-65, 2008 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-18506148

RESUMO

In this study, we investigated the kinetics of oxaliplatin-DNA adduct formation in white blood cells of cancer patients in relation to efficacy as well as oxaliplatin-associated neurotoxicity. Thirty-seven patients with various solid tumours received 130 mg m(-2) oxaliplatin as a 2-h infusion. Oxaliplatin-DNA adduct levels were measured in the first cycle using adsorptive stripping voltammetry. Platinum concentrations were measured in ultrafiltrate and plasma using a validated flameless atomic absorption spectrometry method. DNA adduct levels showed a characteristic time course, but were not correlated to platinum pharmacokinetics and varied considerably among individuals. In patients showing tumour response, adduct levels after 24 and 48 h were significantly higher than in nonresponders. Oxaliplatin-induced neurotoxicity was more pronounced but was not significantly different in patients with high adduct levels. The potential of oxaliplatin-DNA adduct measurements as pharmacodynamic end point should be further investigated in future trials.


Assuntos
Antineoplásicos/sangue , Adutos de DNA/sangue , Leucócitos/metabolismo , Neoplasias/sangue , Compostos Organoplatínicos/sangue , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacologia , Humanos , Compostos Organoplatínicos/efeitos adversos , Compostos Organoplatínicos/farmacologia , Oxaliplatina
6.
J Helminthol ; 79(1): 85-9, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15831118

RESUMO

The platinum group metals (PGM) Pt, Pd and Rh are emitted into the environment mainly by catalytic exhaust gas converters of cars. As PGM accumulate in sediments of aquatic ecosystems, the study was focused on the uptake of the noble metals by European eels, Anguilla anguilla infected with the acanthocephalan Paratenuisentis ambiguus. Eels were exposed to ground catalytic converter material for six weeks. After exposure Pt and Pd were detected in the liver and kidney of the eels and in the parasites. Palladium was also found in fish muscle and intestine. No Rh uptake by the eel tissues and the parasites occurred. Paratenuisentis ambiguus contained the highest levels of both metals with 40 times higher Pt concentrations and four times higher Pd concentrations than the liver of its host. Due to its accumulation capacity for PGM, P. ambiguus can be applied as a sensitive accumulation indicator in field studies to assess the degree of environmental PGM contamination in aquatic ecosystems.


Assuntos
Acantocéfalos/metabolismo , Poluentes Atmosféricos/análise , Anguilla/metabolismo , Anguilla/parasitologia , Automóveis , Helmintíase/metabolismo , Metais/análise , Animais , Ecossistema , Monitoramento Ambiental/métodos , Parasitologia de Alimentos , Alemanha , Interações Hospedeiro-Parasita , Paládio/análise , Platina/análise , Ródio/análise
7.
Environ Res ; 98(1): 83-8, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15721887

RESUMO

Concentrations of the platinum group elements Pt, Pd, and Rh were analyzed by adsorptive cathodic stripping voltammetry (Pt, Rh) and total-reflection X-ray fluorescence (Pd) in the intestinal helminth Pomphorhynchus laevis and its host Barbus barbus. The fish were caught in the Danube river south of the city of Budapest (Hungary) and were exposed to ground catalytic material for 28 days. Following exposure all three precious metals were taken up and accumulated in host organs and the parasites. Interestingly, in all tissues of the unexposed controls Pt was found, whereas Pd was not present in the muscle of the controls and Rh was not detectable in muscle and intestine of unexposed barbel. All metals were found at significantly higher concentrations in the acanthocephalan than in the tissues of barbel. These results are discussed with respect to the application of P. laevis as an accumulation indicator for metals.


Assuntos
Acantocéfalos/metabolismo , Paládio/farmacocinética , Platina/farmacocinética , Rênio/farmacocinética , Poluentes Químicos da Água/farmacocinética , Animais , Biomarcadores/metabolismo , Cyprinidae/metabolismo , Cyprinidae/parasitologia , Monitoramento Ambiental/métodos , Intestinos/parasitologia , Paládio/análise , Platina/análise , Rênio/análise , Rios , Estatísticas não Paramétricas , Poluentes Químicos da Água/análise
8.
Anal Bioanal Chem ; 380(1): 54-8, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15278335

RESUMO

Oxaliplatin, a novel diaminocyclohexane-platinum complex, is used for the treatment of metastatic colorectal cancer. The amount of DNA-adduct formation of this drug in white blood cells of patients is determined after isolation of the DNA by density gradient centrifugation and a four-step solid phase extraction procedure. DNA is quantified by UV spectrometry, and platinum is determined after mineralization of the DNA sample by adsorptive stripping voltammetry (formazone method). It is possible to determine Pt-nucleotide ratios in clinical samples down to five Pt atoms in 10(8) nucleotides, and the dynamic range of the method covers three orders of magnitude. An absolute amount of 25 microg of DNA is sufficient for such measurements. With the method described, the time-dependent formation of oxaliplatin DNA adducts can be monitored in clinical studies, which may help us to understand inter-individual differences in the responses of patients to oxaliplatin-based therapy.


Assuntos
DNA/química , Compostos Organoplatínicos/administração & dosagem , Platina/análise , DNA/isolamento & purificação , Humanos , Leucócitos/química , Estrutura Molecular , Oxaliplatina , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta/métodos
9.
Eur J Cancer ; 40(5): 696-700, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15010070

RESUMO

Male germ cell tumour patients treated with cisplatin-based chemotherapy frequently develop cardiovascular risk factors and disease, but sparse information is available about long-term complications of this type of chemotherapy in women. We investigated the prevalence of cardiovascular risk factors and vascular damage in 21 women (median age 39 years; range 26-57 years) with an epithelial or germ cell tumour of the ovary cured by cisplatin-based chemotherapy after a median follow-up of 14 years (range 3-21 years). Hypercholesterolaemia was present in 62%, obesity in 24%, hypertension in 14%, insulin resistance in 14%, and microalbuminuria in 24% of patients. Microalbuminuria was more frequent in long-term cancer survivors than in a female background population with a similar age (23.8 versus 3.2%; P<0.05). A substantial portion of young female patients cured by cisplatin-based chemotherapy are likely to develop cardiovascular risk factors and signs of endothelial damage at an early stage.


Assuntos
Antineoplásicos/efeitos adversos , Doenças Cardiovasculares/induzido quimicamente , Cisplatino/efeitos adversos , Germinoma/tratamento farmacológico , Neoplasias Epiteliais e Glandulares/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Adulto , Índice de Massa Corporal , Colesterol/sangue , Feminino , Seguimentos , Germinoma/sangue , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/sangue , Fatores de Risco , Sobreviventes
10.
Environ Sci Technol ; 35(10): 1996-2000, 2001 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-11393979

RESUMO

Increases in platinum group element (PGE) concentrations in ambient air and dust since the introduction of automotive catalytic converters in 1988 is a cause of concern. Until now, data derived from engine-test bench experiments have provided the basis for the assessment of human health risks associated with PGE exposure. Such experiments have provided valuable information regarding emission data that has been used to estimate ambient exposure concentrations. However, these data are not necessarily representative of typical environmental PGE exposure levels and conditions. Data on measured environmental concentrations is needed to provide a more adequate basis for the assessment of exposure and related risks. Twenty air and airborne-dust samples were provided by the Umweltbundesamt (Federal Environmental Agency, Germany) in the years 1988, 1989, 1992, 1997, and 1998. The samples were collected in Frankfurt/Main and the adjacent city of Offenbach. For this, 11 to 80 m3 of air were filtered over a 24-72 h period using a vacuum. Glass-fiber filters were used to collect samples. Sample platinum and rhodium concentrations were determined using adsorptive voltammetry. Although the number of samples collected in different years is limited, the results indicate a trend toward continuous increases in ambient concentrations of these metals between 1988 and 1998. Specifically, there were 46- and 27-fold increases in Pt and Rh concentrations, respectively. Despite these observed increases, the Pt concentrations measured (i.e., 147 pg/m3 on average, with a maximum of 246 pg/m3 in 1998) fell far below 15,000 pg/m3, which has been suggested as a guidance value (i.e., exposure at this level would be expected to be without appreciable health risk). The results of a particle-size distribution analysis of one sample (8-step impactor) that was collected 150 m away from a street show that approximately 75% of Pt and 95% of Rh occurs in association with large particulate matter of > 2 microns, with concentrations reaching a maximum in particles of 4.7 to 5.8 microns. The remaining 25% of Pt and 5% of Rh is present in fine particulate matter of < 2 microns. An approximate 10% of Pt and < 38% of Rh in airborne particles was found to be soluble in 0.1 molar HCl. Further, the results indicate that most of the emitted PGE particles from automotive catalytic converters, particularly those bound to fine particulate matter, are capable of being airborne. As a result, PGEs are not only present in areas close to emissions (e.g., roads), but can be transported over longer distances.


Assuntos
Poluentes Atmosféricos/análise , Exposição Ambiental , Platina/análise , Ródio/análise , Movimentos do Ar , Catálise , Monitoramento Ambiental , Filtração , Alemanha , Humanos , Tamanho da Partícula , Saúde Pública , Valores de Referência , Medição de Risco , Sensibilidade e Especificidade , Emissões de Veículos
11.
Environ Pollut ; 113(3): 341-5, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11428142

RESUMO

Following the introduction of automobile catalysts in the middle of the 1980s in Germany there is an increasing emission of the platinum-group-metals platinum, palladium (Pd) and rhodium. Still, it remains unclear if these metals are bioavailable for aquatic animals and to which extent they become accumulated by the aquatic biosphere. Because of analytical problems in detecting Pd in small biological samples the present investigation concentrates on the bioavailability of this metal. To answer the question of a Pd uptake by aquatic organisms experimental studies were conducted with European eels maintained in water containing road dust at a concentration of 10 kg/100 l. Following an exposure period of four weeks, samples of liver and kidney were analysed by total-reflection X-ray fluorescence analysis after co-precipitation of Pd with mercury. These experiments revealed an uptake of traffic related Pd by European eels which showed a mean liver Pd concentration of 0.18 +/- 0.05 ng/g (wet wt.), whereas the Pd concentration in the kidney ranged below the detection limit. Thus, in this study we can demonstrate for the first time that automobile catalyst emitted Pd is bioavailable for aquatic animals.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Anguilla/fisiologia , Paládio/farmacocinética , Emissões de Veículos/análise , Animais , Disponibilidade Biológica , Catálise , Exposição Ambiental , Rim/química , Fígado/química , Ródio/farmacocinética
12.
Ther Drug Monit ; 23(2): 169-73, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11294519

RESUMO

Patients cured of metastatic testicular cancer with cisplatin chemotherapy may suffer late adverse effects even after 20 years. The cause of these late adverse effects has not been elucidated yet. One cause might be prolonged tissue retention of platinum in these patients. Therefore, an extremely sensitive method for measuring platinum in plasma was used to investigate whether platinum is still detectable in plasma 10 to 20 years after cisplatin chemotherapy. High-pressure decomposition of plasma is followed by adsorptive voltametric determination of platinum, with a limit of quantification of 6 pg/g plasma. This procedure appeared suitable for the measurement of platinum in 44 former patients with platinum levels ranging from 22 to 140 pg/g plasma. This method is approximately 6000 times more sensitive than the standard flameless atomic absorption spectrophotometry (AAS) method. The platinum levels of these 44 patients were significantly elevated when compared with 20 control patients who were cured of testicular cancer but did not receive cisplatin chemotherapy (p < 0.001). There was a significant correlation between plasma platinum concentrations and follow-up time after cisplatin administration (r = -0.658, p < 0.001). This study shows that patients with testicular cancer who were treated with cisplatin can retain platinum in their body for at least 20 years. More data are needed to investigate whether there is a relation between the prolonged retention of platinum and long-term toxicity.


Assuntos
Antineoplásicos/sangue , Cisplatino/sangue , Platina/sangue , Neoplasias Testiculares/sangue , Adolescente , Adulto , Antineoplásicos/uso terapêutico , Cisplatino/uso terapêutico , Seguimentos , Humanos , Indicadores e Reagentes , Masculino , Pessoa de Meia-Idade , Espectrofotometria Atômica , Neoplasias Testiculares/tratamento farmacológico
13.
Fresenius J Anal Chem ; 371(7): 921-6, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11769801

RESUMO

The species patterns of nutrient and trace metals (K, Ca, Mg, Mn, Fe, Zn) obtained by extraction of plant roots have been determined as a function of extraction pH in the range 4-9. The extractable metal concentrations were subdivided into low-molecular-weight (<10 kDa) and high-molecular-weight (>10 kDa) metal species by TXRF analysis. Except for pH 9, the low-molecular-weight fraction is predominant. This fraction was further separated by HPLC with AAS detection. It was demonstrated that the nature of the metal species changes dramatically when the extraction pH is changed, especially in the range 9-7. Information about the chemical nature of chromatographically separated metal species is obtained by use of different electrochemical detectors (amperometric detection at a glassy carbon or copper electrode and pulsed amperometric detection) and diode-array UV detection.


Assuntos
Metais/química , Extratos Vegetais/química , Raízes de Plantas/química , Cálcio/análise , Cálcio/química , Cálcio/isolamento & purificação , Concentração de Íons de Hidrogênio , Ferro/análise , Ferro/química , Ferro/isolamento & purificação , Manganês/análise , Manganês/química , Manganês/isolamento & purificação , Metais/análise , Metais/isolamento & purificação , Compostos Organometálicos/análise , Compostos Organometálicos/química , Compostos Organometálicos/isolamento & purificação , Potássio/análise , Potássio/química , Potássio/isolamento & purificação , Manejo de Espécimes , Espectrofotometria Atômica , Zinco/análise , Zinco/química , Zinco/isolamento & purificação
14.
Analyst ; 125(3): 397-9, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10829339

RESUMO

The reductive co-precipitation of trace and ultra-trace elements together with mercury followed by complete evaporation of the mercury makes it possible to determine palladium and gold by total reflection X-ray fluorescence. Both elements can be detected without interferences at optimal sensitivity in the pg range. Thus, detection limits of, e.g., 2.5 ng L-1 for palladium and 2.0 ng L-1 for gold, in urine, were obtained. The precision was determined to 0.04 at a palladium concentration of about 200 ng L-1 urine and to 0.19 at a gold concentration of only 18 ng L-1. The recovery for a urine sample spiked with known amounts of palladium and gold amounted to > 95%. Results of the combined procedure are given for the determination of palladium and gold in the urine of non-exposed and occupationally exposed persons and in some other environmentally relevant samples.


Assuntos
Ouro/urina , Paládio/urina , Poluentes Ambientais/análise , Humanos , Exposição Ocupacional , Espectrometria por Raios X/métodos
15.
Lancet ; 355(9209): 1075-6, 2000 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-10744098

RESUMO

We have shown in patients cured from metastatic testicular cancer that up to 20 years after administration of cisplatin-containing chemotherapy, circulating platinum is still detectable in plasma. This finding may influence the development of long-term, treatment-related side-effects.


Assuntos
Cisplatino/farmacocinética , Platina/farmacocinética , Neoplasias Testiculares/sangue , Adolescente , Adulto , Cisplatino/administração & dosagem , Seguimentos , Humanos , Masculino , Taxa de Depuração Metabólica/fisiologia , Neoplasias Testiculares/tratamento farmacológico
16.
Fresenius J Anal Chem ; 367(4): 356-8, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11225860

RESUMO

FIA with pulsed amperometric detection (PAD) is used for the determination of metal-binding carbohydrates in plant extracts. Results of direct FIA measurements agree very well with those of corresponding HPLC-PAD analyses. The proposed method is used to determine total carbohydrates in isolated low-molecular-weight fractions of plant roots, which have been obtained after extraction at different pH values. The results are compared with those obtained by corresponding metal determinations (Ca, Mg, Zn, Mn) by AAS and also with constant potential amperometric detection at a copper working electrode. The latter detection mode is more sensitive, but less selective for carbohydrates.


Assuntos
Carboidratos/análise , Eletroquímica/métodos , Análise de Injeção de Fluxo/métodos , Raízes de Plantas/química , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Metais/química , Extratos Vegetais
17.
Can Rev Sociol Anthropol ; 35(3): 325-44, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11542273

RESUMO

The events surrounding the 1986 decision to launch the Space Shuttle Challenger are reconstructed to illustrate how multiple masculinities, particularly between and among managers and engineers, contributed to that organizational crisis. An analysis of gendered power relations--especially among men--reveals how the construction of particular forms of "masculinities," and the ways in which they are reproduced, rationalized or resisted, vary as a result of contextual changes. Commonalities and differences among these masculinities are discussed. We close by exploring possible contradictions in the construction of organizational masculinities and their implications for organizational practice.


Assuntos
Acidentes Aeronáuticos/psicologia , Tomada de Decisões , Homens/psicologia , Cultura Organizacional , Voo Espacial/organização & administração , United States National Aeronautics and Space Administration/organização & administração , Autoritarismo , Falha de Equipamento , Feminino , Processos Grupais , Humanos , Relações Interprofissionais , Liderança , Masculino , Objetivos Organizacionais , Personalidade , Assunção de Riscos , Caracteres Sexuais , Fatores Sexuais , Voo Espacial/instrumentação , Astronave/instrumentação , Estados Unidos
18.
Z Lebensm Unters Forsch ; 201(4): 303-6, 1995 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-8525695

RESUMO

In the People's Republic of China there are wide regions where many people suffer from strong selenium deficiency. In order to elucidate the possibilities to compensate this state of need by the national drink, the selenium contents of 31 tea samples from nine provinces of the PR China were determined by hydride generation atomic absorption spectrometry (HG-AAS). The Se contents of the ten analyzed tea samples from one region with soils containing high selenium amounts range from 83 ng/g to 7530 ng/g. These results are in contrast to the Se contents of the remaining tea samples from other regions, which range from 28 to 573 ng/g. The extractable part of selenium in the tea drink ranges between 7% and 27% without significant difference among different tea samples. The accuracy of Se determination was tested by using one tea standard reference material. The daily consumption of one "Se tea" examined in this study assures that people who suffer from a Se deficiency resume enough of it. Drinking normal quantities of this tea an intoxication by Se is not to be expected.


Assuntos
Selênio/análise , Selênio/deficiência , Chá/química , China , Geografia , Humanos , Padrões de Referência , Espectrofotometria Atômica
19.
Electrophoresis ; 16(5): 800-3, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7588565

RESUMO

Model experiments for the detection of platinum species in extracts from native and platinum-treated grass cultivations are described. The procedural steps are cultivation of the grass samples, extraction and concentration of the platinum species by ultrafiltration and freeze-drying, preparative separation of the species by gel chromatography followed by isotachophoresis, and sequential analytical detection of the separated platinum species by adsorptive voltammetry. After isotachophoresis, sharp peaks of platinum species could be detected. In the native grass extract only one platinum species (160-200 kDa) was found. In the platinum-treated grass extracts several platinum species were observed in the molecular mass range from 1 to > 1000 kDa. By an extremely sensitive platinum determination method (adsorptive voltammetry; detection limit, 2 pg Pt abs.) it was possible to detect platinum even in stained protein bands from horizontal gel electrophoresis of platinum containing fractions obtained after isotachophoresis.


Assuntos
Cromatografia/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Platina/análise , Poaceae/química , Resinas Acrílicas/química , Géis/química
20.
Dtsch Zahnarztl Z ; 46(2): 154-8, 1991 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-1814712

RESUMO

The mercury concentrations in the hair of 53 dentists, 49 dental assistants, 35 dental students and 35 non-exposed persons were analyzed by AAS and compared with a group of 22 factory workers producing chloride gas. The average mercury concentrations in the hair of the dentists was found to be twice as high as the amount measured in the non-exposed population, but only one quarter of that established for the factory workers. The dental assistants had 50% more mercury in their hair than the non-exposed group. The mercury concentrations did not correlate with age, sex, or number of amalgam fillings, but rather with the daily/weekly consumption of fish. The mercury concentrations in the hair of dentists and dental personnel found in this study were low, even when compared with international results; toxicologically their importance is negligible.


Assuntos
Odontólogos , Cabelo/química , Mercúrio/análise , Exposição Ocupacional , Adolescente , Adulto , Animais , Amálgama Dentário/efeitos adversos , Assistentes de Odontologia , Feminino , Peixes , Humanos , Masculino , Pessoa de Meia-Idade , Espectrofotometria Atômica , Estudantes de Odontologia
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