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1.
PeerJ ; 11: e15775, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37525661

RESUMO

Lower limb robotic exoskeletons are often studied in the context of steady state treadmill walking in a laboratory environment. However, the end goal for exoskeletons is to be used in real world, complex environments. To reach the point that exoskeletons are openly adopted into our everyday lives, we need to understand how the human and robot interact outside of a laboratory. Metabolic cost is often viewed as a gold standard metric for measuring exoskeleton performance but is rarely used to evaluate performance at non steady state walking outside of a laboratory. In this study, we tested the effects of robotic ankle exoskeletons under proportional myoelectric control on the cost of transport of walking both inside on a treadmill and outside overground. We hypothesized that walking with the exoskeletons would lead to a lower cost of transport compared to walking without them both on a treadmill and outside. We saw no significant increases or decreases in cost of transport or exoskeleton mechanics when walking with the exoskeletons compared to walking without them both on a treadmill and outside. We saw a strong negative correlation between walking speed and cost of transport when walking with and without the exoskeletons. In the future, research should consider how performing more difficult tasks, such as incline and loaded walking, affects the cost of transport while walking with and without robotic ankle exoskeletons. The value of this study to the literature is that it emphasizes the importance of both hardware dynamics and controller design towards reducing metabolic cost of transport with robotic ankle exoskeletons. When comparing our results to other studies using the same hardware with different controllers or very similar controllers with different hardware, there are a wide range of outcomes as to metabolic benefit.


Assuntos
Tornozelo , Exoesqueleto Energizado , Humanos , Eletromiografia/métodos , Metabolismo Energético , Fenômenos Biomecânicos , Caminhada
2.
Chemosphere ; 190: 80-89, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28985539

RESUMO

Veterinary medicines can be extremely damaging to the environment, as seen with the catastrophic declines in Gyps vulture in South Asia due to their secondary exposure to diclofenac in their primary food source. Not surprisingly, concern has been raised over other similar drugs. In this study, we evaluate the toxicity of carprofen to the Gyps vulture clade through plasma pharmacokinetics evaluations in Bos taurus cattle (their food source) and Gyps africanus (a validated model species); tissue residues in cattle; and the effect of carprofen as a secondary toxicant as both tissue-bound residue or pure drug at levels expected in cattle tissues. Carprofen residues were highest in cattle kidney (7.72 ± 2.38 mg/kg) and injection site muscle (289.05 ± 98.96 mg/kg of dimension of 5 × 5 × 5 cm). Vultures exposed to carprofen as residues in the kidney tissue or pure drug equivalents showed no toxic signs. When exposed to average injection site concentrations (64 mg/kg) one of two birds died with evidence of severe renal and liver damage. Toxicokinetic analysis revealed a prolonged drug half-life of 37.75 h in the dead bird as opposed to 13.99 ± 5.61 h from healthy birds dosed intravenously at 5 mg/kg. While carprofen may generally be harmless to Gyps vultures, its high levels at the injection site in treated cattle can result in lethal exposure in foraging vultures, due to relative small area of tissue it is found therein. We thus suggest that carprofen not be used in domesticated ungulates in areas where carcasses are accessible or provided to vultures at supplementary feeding sites.


Assuntos
Carbazóis/toxicidade , Falconiformes , Drogas Veterinárias/toxicidade , Animais , Anti-Inflamatórios não Esteroides/farmacocinética , Anti-Inflamatórios não Esteroides/toxicidade , Ásia , Carbazóis/farmacocinética , Bovinos , Morte , Diclofenaco/farmacocinética , Diclofenaco/toxicidade , Meia-Vida , Rim/efeitos dos fármacos , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Toxicocinética , Drogas Veterinárias/farmacocinética
3.
Geburtshilfe Frauenheilkd ; 77(2): 149-157, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28331237

RESUMO

Axillary lymph node status remains an important prognostic factor in early breast cancer. It is regarded as an indicator for (neo)adjuvant systemic treatment and postoperative radiotherapy of the regional lymphatics. Commenced in September 2015, the INSEMA trial is investigating whether operative determination of nodal status as part of breast conserving therapy (BCT) for early stage breast cancer (c/iT1-2 c/iN0) can be avoided without reducing oncological safety. After inclusion of 1001 patients there was general acceptance of the complex study design by patients and study doctors so that recruitment for the first randomisation (axillary sentinel lymph node biopsy [SLNB]: yes or no) achieved predicted case numbers. The second randomisation however (SLNB alone versus complete axillary dissection when one or two macrometastases are present at SLNB) recruited fewer cases than expected for the following three reasons: a) the 13 % rate of one or two macrometastases after SLNB in the INSEMA trial collective was lower than expected; b) around 20 % of patients refused the second randomisation; c) there was delayed inclusion of the Austrian study centres, which only recruited for the second randomisation. Lack of knowledge of nodal status when SLNB is avoided represents a new challenge for the postoperative tumour board. In particular decisions on chemotherapy for luminal-like tumours and irradiation of the lymphatics (excluding axilla) must be guided by tumour biological parameters. The INSEMA trial does not provide answers to some important questions, e.g. it remains unclear whether patients without SLNB can be offered partial breast irradiation alone in low-risk situations and whether SLNB can also be avoided in patients with stage T1-2 tumours who have a mastectomy indication.

4.
Environ Res ; 152: 150-156, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27771569

RESUMO

Vulture populations in southern Africa have been on the decline for years, which unlike the Asian vulture crisis, has no one specific cause. Reasons attributable are deliberate and secondary poisonings, drowning, power line injuries, electrocutions, traditional medicine ("muti" trade) and calcium deficiencies. However, lead toxicity as a potential causal factor is hardly mentioned. The potential for lead toxicity needs to be considered as substantial game hunting occurs in the region with little regulatory control on bullet types. In this study, we determined the whole blood lead concentrations of captive and wild vulture populations in South Africa and Namibia (n=185). Results were compared to previous published ranges indicative of background exposure (<10µg/dL), non-toxic point exposure based upon the range established from captive birds and subclinical exposure. In general, whole blood lead concentrations were higher for wild African White-backed vultures (Gyps africanus)(AWBV) than Cape vultures (G. coprotheres)(CGV) at 15.54±12.63µg/dL vs 12.53±8.88µg/dL (non-significantly different), while in the Bearded vultures (Gypaetus barbatus) no indication of exposure was evident. Very similar exposures resulted irrespective of the birds being in captivity or under wild, free-roaming conditions. A proportion of wild birds did, however, appear to be exposed to another source of lead than purely environmental (±12% and 30.6% for AWBV and CGV respectively). One bird, which had a whole blood concentration of 100µg/dL, died soon after capture. To find the relationship between whole blood lead concentration and likely exposure factors, birds were compared by their rural/urban location, vicinity to mines and surrounding soil lead concentrations. With no relationship being present for the latter factors, we believe that this is evidence that the portion of southern African vultures being exposed to unknown source of lead, which we suggest arises from leaded ammunition remaining from hunting.


Assuntos
Exposição Ambiental , Poluentes Ambientais/sangue , Falconiformes/sangue , Falconiformes/metabolismo , Chumbo/sangue , Animais , Monitoramento Ambiental , Mineração , Dinâmica Populacional , África do Sul
5.
Ultramicroscopy ; 162: 82-90, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26799327

RESUMO

The indentation modulus of thin films of porous organosilicate glass with a nominal porosity content of 30% and thicknesses of 350nm, 200nm, and 46nm is determined with help of atomic force acoustic microscopy (AFAM). This scanning probe microscopy based technique provides the highest possible depth resolution. The values of the indentation modulus obtained for the 350nm and 200nm thin films were respectively 6.3GPa±0.2GPa and 7.2GPa±0.2GPa and free of the substrate influence. The sample with the thickness of 46nm was tested in four independent measurement sets. Cantilevers with two different tip radii of about 150nm and less than 50nm were applied in different force ranges to obtain a result for the indentation modulus that was free of the substrate influence. A detailed data analysis yielded value of 8.3GPa±0.4GPa for the thinnest film. The values of the indentation modulus obtained for the thin films of porous organosilicate glasses increased with the decreasing film thickness. The stiffening observed for the porous films could be explained by evolution of the pore topology as a function of the film thickness. To ensure that our results were free of the substrate influence, we analyzed the ratio of the sample deformation as well as the tip radius to the film thickness. The results obtained for the substrate parameter were compared for all the measurement series and showed, which ones could be declared as free of the substrate influence.

6.
Artigo em Inglês | MEDLINE | ID: mdl-26737768

RESUMO

In this study we demonstrate the sensing capabilities of a portable multiplex measurement system for FET-based (bio)chemical sensors with an integrated microfluidic interface. We therefore conducted pH measurements with Silicon Nanoribbon FET-based Sensors using different measurement procedures that are suitable for various applications. We have shown multiplexed measurements in aqueous medium for three different modes that are mutually specialized in fast data acquisition (constant drain current), calibration-less sensing (constant gate voltage) and in providing full information content (sweeping mode). Our system therefore allows surface charge sensing for a wide range of applications and is easily adaptable for multiplexed sensing with novel FET-based (bio)chemical sensors.


Assuntos
Técnicas Biossensoriais , Transistores Eletrônicos , Concentração de Íons de Hidrogênio , Técnicas Analíticas Microfluídicas , Nanotubos de Carbono/química , Silício/química , Água/química
7.
Nanotechnology ; 24(35): 355703, 2013 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-23938222

RESUMO

We have used the atomic force acoustic microscopy (AFAM) method to determine the indentation modulus of nanoporous thin-film materials with ultralow values of dielectric permittivity (dielectric constant k < 2.4). The AFAM method is based on the contact mode of atomic force microscopy (AFM) and as such is able to characterize materials with high spatial resolution. The tested material was porous organosilicate glass with nominal porosity ranging from 27% to 40%. The values obtained for the indentation modulus varied from 4 to 7 GPa depending on the pore concentration. The values obtained for the indentation modulus by use of the AFAM method were in very good agreement with those determined by nanoindentation. In addition, a part of the AFAM results obtained for the sample with the highest porosity content showed dependence of the effective indentation modulus on the applied load. Preliminary data analysis suggests that the stress rate is the critical factor in triggering this particular mechanical response of the porous material.

8.
Rofo ; 185(2): 116-20, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23371867

RESUMO

PURPOSE: To evaluate the feasibility of transperineal MR-guided prostate biopsy using a stereotactical targeting system originally designed for anorectal usage. MATERIALS AND METHODS: A commercially available DynaTRIM MR targeting system (Invivo corp., Gainesville FL, USA) originally designed only for anorectal application was used on a 70 cm wide-bore, whole-body 3 Tesla MR-system (Ingenia, Philips Healthcare, Best, NL). Transperineal biopsy was performed following mulitparametric MR imaging for targeting of the lesion. RESULTS: The anorectal device allowed for correct localization and successful MR-guided transperineal biopsy of the targeted lesion. CONCLUSION: MR-guided transperineal biopsy is feasible using a commercially available anorectal stereotactic biopsy device. This may lead to a broader acceptance of this approach for targeted prostate biopsies.


Assuntos
Biópsia Guiada por Imagem/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Neoplasias da Próstata/patologia , Técnicas Estereotáxicas/instrumentação , Idoso , Desenho de Equipamento , Análise de Falha de Equipamento , Estudos de Viabilidade , Humanos , Masculino , Períneo/patologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
9.
Rev Sci Instrum ; 83(4): 043703, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22559535

RESUMO

We propose an improved system that enables simultaneous excitation and measurements of at least two resonance frequency spectra of a vibrating atomic force microscopy (AFM) cantilever. With the dual resonance excitation system it is not only possible to excite the cantilever vibrations in different frequency ranges but also to control the excitation amplitude for the individual modes. This system can be used to excite the resonance frequencies of a cantilever that is either free of the tip-sample interactions or engaged in contact with the sample surface. The atomic force acoustic microscopy and principally similar methods utilize resonance frequencies of the AFM cantilever vibrating while in contact with the sample surface to determine its local elastic modulus. As such calculation demands values of at least two resonance frequencies, two or three subsequent measurements of the contact resonance spectra are necessary. Our approach shortens the measurement time by a factor of two and limits the influence of the AFM tip wear on the values of the tip-sample contact stiffness. In addition, it allows for in situ observation of processes transpiring within the AFM tip or the sample during non-elastic interaction, such as tip fracture.

10.
J S Afr Vet Assoc ; 82(1): 24-31, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21826834

RESUMO

South Africa is home to 9 vulture species, of which 7 are endangered. While the cause of the population declines remains largely speculative, a vast amount of effort has been dedicated towards the protection of populations by ensuring sustainable and safe food sources for the various colonies. Limited focus was placed in the past on efforts related to the rescue and/or rehabilitation (R&R) of injured birds and the release of these birds back into the wild. This paper provides an overview of the causes, the impact and success of 3 organisations involved in R&R efforts of vultures in the Magaliesberg mountain range and surrounding areas over a period of 10 years. Study material included 162 Cape griffon (CGV) and 38 African white-backed (AWBV) vultures. Datasets include the number, sex and age of birds received, the reason the vultures were brought in for R&R, surgical interventions performed and outcomes of rescue efforts. The CGV dominated the rehabilitation attempts. Results further show that a large number of apparently healthy birds were presented for veterinary treatment. The R&R data clearly indicate that the major cause of injuries was birds colliding with overhead pylons, as a high number of soft tissue and skeletal injuries were observed. The study also shows that successful releases of rescued birds are possible. It is concluded that urbanisation has had a major negative impact on vultures around the Magaliesberg mountain range.


Assuntos
Espécies em Perigo de Extinção , Falconiformes , Bem-Estar do Animal , Animais , Cidades , Conservação dos Recursos Naturais , Feminino , Cabeça , Masculino , Caracteres Sexuais , África do Sul
11.
J Pediatr Adolesc Gynecol ; 23(4): 209-14, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20471875

RESUMO

STUDY OBJECTIVE: To examine vitamin D and parathormone (PTH) levels in adolescents who experienced substantial bone mineral density (BMD) loss during depot medroxyprogesterone acetate (DMPA) use. DESIGN: A non-randomized, multi-center study, during which DMPA was administered every 12 weeks and evaluation of lumbar spine and hip BMD by dual-energy X-ray absorptiometry (DXA) was conducted every 6 months. A blood sample for vitamin D and PTH measurements was obtained from adolescents who experienced >5% BMD loss. Vitamin D deficiency was defined as 25-hydroxyvitamin D (25OHD) level of <20 ng/mL, insufficiency as 25OHD level of 20-30 ng/mL, and sufficiency as 25OHD level of >30 ng/mL. RESULTS: Evaluation of vitamin D and PTH was carried out in 15 participants who experienced BMD loss of > or = 5% during DMPA use. At initiation of DMPA, participants had mean (+SE) age 17+1 years, gynecologic age 61+4 months, and body mass index 24+1.5 kg/m2. Racial/ethnic distribution was: Caucasian--7 girls, Hispanic--4 girls, African-American--3 girls, and other--1 girl. Six participants had BMD loss of >5% after 2 DMPA injections, five after 3 injections, one after 5 injections, one after 8 injections, one after 10 injections, and one after 13 injections. Only one girl (7%) had sufficient vitamin D. The other participants had vitamin D insufficiency (50%) or deficiency (43%). Participants' mean (+SE) PTH was 22+4 pg/mL (reference range 7-53 pg/mL), and mean (+SE) 1,25-dihydroxyvitamin D was 56+5 pg/mL (reference range 22-67 pg/mL). CONCLUSIONS: Inadequate vitamin D status was evident among the majority of female adolescents who experienced a substantial BMD loss while using DMPA.


Assuntos
Densidade Óssea/efeitos dos fármacos , Doenças Ósseas Metabólicas/etiologia , Anticoncepcionais Femininos/efeitos adversos , Acetato de Medroxiprogesterona/efeitos adversos , Deficiência de Vitamina D/complicações , Adolescente , Implantes de Medicamento , Feminino , Humanos , Hormônio Paratireóideo/sangue , Projetos Piloto , Vitamina D/sangue
12.
Arch Toxicol ; 84(10): 761-6, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20140424

RESUMO

In a safety study, Cape Griffon vultures (Gyps coprotheres) were dosed with ketoprofen at single doses of ~1 mg/kg (n = 5) and 5 mg/kg (n = 11). No toxicity was reported in the 1 mg/kg group, with the AUC(inf), V(z) and Cl being 10.42 µg/ml h, 0.37 l/kg and 0.10 l/h kg, respectively. Toxicity occurred in the 5 mg/kg group, with 7 of the 11 birds dying. Clinical signs of toxicity included depression, loss of appetite and apparent coma. Animals died within 48 h of dosing. The AUC(inf), V(z) and Cl in the birds that survived were 52.26 µg/ml h, 0.45 l/kg and 0.10 l/h kg, respectively. The AUC(inf), V(z) and Cl in the birds those died were 207.90 µg/ml h, 0.26 l/kg and 0.02 l/h kg, respectively. Based on the increase in the AUC(inf) and C(max) in the birds that died, we surmise that toxicity resulted from saturation of the metabolic process. While the exact metabolic pathway remains unknown in these vultures, we believe that toxicity may be due to pharmacogenomic differences in the cytochrome P450 pathway.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Falconiformes/metabolismo , Cetoprofeno/toxicidade , Animais , Anti-Inflamatórios não Esteroides/sangue , Anti-Inflamatórios não Esteroides/farmacocinética , Área Sob a Curva , Relação Dose-Resposta a Droga , Falconiformes/sangue , Cetoprofeno/sangue , Cetoprofeno/farmacocinética , Testes de Toxicidade
13.
Regul Toxicol Pharmacol ; 53(3): 205-8, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19545505

RESUMO

Veterinary diclofenac has been responsible for the devastation of three species of Gyps vulture on the Indian subcontinent, and it is now regarded as one of the worst environmental contaminants in the recent past. While measures have been taken to control the manufacture of veterinary diclofenac in South Asia, the promotion of diclofenac on the African continent poses a risk to vultures in this region. In Southern Africa, the species of greatest conservation concern is the Cape Griffon Vulture (Gyps coprotheres), as only 2900 breeding pairs remain in the wild. The objective of this study was to test if this species is toxicologically sensitive to diclofenac. In a single dose-toxicity study, two adult Cape Griffon Vultures with severe injuries, that were considered to have a very poor prognostic outcome, were dosed intravenously with diclofenac at 0.8mg/kg. The changes in the clinical pathology were compared to the normal reference range established for 24 healthy Cape Griffon Vultures. Both birds died within 48h of dosing. The clinical signs, clinical pathology, gross pathology and histopathological finding were typical for diclofenac toxicity. It would appear that the sensitivity of the Cape Griffon is similar to that of their Asian counterparts and the African White-backed Vulture (Gyps africanus). Diclofenac is almost certainly toxic to all Gyps vultures species and strong efforts must be taken to ensure that veterinary diclofenac products are not licensed or introduced to the African continent.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Doenças das Aves/tratamento farmacológico , Diclofenaco/toxicidade , Espécies em Perigo de Extinção , Falconiformes/lesões , Ferimentos e Lesões/tratamento farmacológico , Ferimentos e Lesões/veterinária , África , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/farmacocinética , Anti-Inflamatórios não Esteroides/uso terapêutico , Diclofenaco/administração & dosagem , Diclofenaco/farmacocinética , Diclofenaco/uso terapêutico , Falconiformes/sangue , Injeções Intravenosas , Distribuição Tecidual , Ácido Úrico/sangue
14.
Onderstepoort J Vet Res ; 75(2): 95-102, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18788202

RESUMO

Sera from 19 wild caught vultures in northern Namibia and 15 (12 wild caught and three captive bred but with minimal histories) in North West Province, South Africa, were examined by an enzyme-linked immunosorbent assay (ELISA) for antibodies to the Bacillus anthracis toxin protective antigen (PA). As assessed from the baseline established with a control group of ten captive reared vultures with well-documented histories, elevated titres were found in 12 of the 19 (63%) wild caught Namibian birds as compared with none of the 15 South African ones. There was a highly significant difference between the Namibian group as a whole and the other groups (P < 0.001) and no significant difference between the South African and control groups (P > 0.05). Numbers in the Namibian group were too small to determine any significances in species-, sex- or age-related differences within the raw data showing elevated titres in four out of six Cape Vultures, Gyps coprotheres, six out of ten White-backed Vultures, Gyps africanus, and one out of three Lappet-faced Vultures, Aegypius tracheliotus, or in five of six males versus three of seven females, and ten of 15 adults versus one of four juveniles. The results are in line with the available data on the incidence of anthrax in northern Namibia and South Africa and the likely contact of the vultures tested with anthrax carcasses. It is not known whether elevated titre indicates infection per se in vultures or absorption of incompletely digested epitopes of the toxin or both. The results are discussed in relation to distances travelled by vultures as determined by new tracking techniques, how serology can reveal anthrax activity in an area and the issue of the role of vultures in transmission of anthrax.


Assuntos
Antraz/veterinária , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Bacillus anthracis/imunologia , Doenças das Aves/epidemiologia , Falconiformes , África Austral/epidemiologia , Fatores Etários , Animais , Antraz/epidemiologia , Antraz/transmissão , Doenças das Aves/transmissão , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Cadeia Alimentar , Masculino , Estudos Soroepidemiológicos , Fatores Sexuais , Especificidade da Espécie
15.
J Vet Pharmacol Ther ; 31(2): 128-34, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18307504

RESUMO

Vulture populations across the Asian subcontinent have declined dramatically in the last 15 years and are now on the verge of extinction. Although the cause of the population decline was initially unknown, the decrease has recently been conclusively linked to the use of the nonsteroidal anti-inflammatory drug diclofenac in cattle that inadvertently ended up in the vulture food chain. With the vulture numbers continuing to decline by up to 48% a year, the Indian, Nepali and Pakistan governments have recently banned the manufacture and importation of veterinary diclofenac. They have also suggested meloxicam as an alternate anti-inflammatory for use in cattle. This recommendation was based on extensive acute safety studies in the African White-backed vulture (Gyps africanus), which evaluated worst case scenarios of maximum intake based on a once in three day feeding pattern. However, the possible cumulative pharmacokinetic and pharmacodynamic effects in vultures receiving multiple daily doses of meloxicam over time were not assessed. At present very little pharmacokinetic or pharmacodynamic information is available to add further support for the safety of meloxicam in this animal species. This article discusses the oral and intramuscular pharmacokinetics of meloxicam in Cape Griffon vultures (Gyps coprotheres). Therapeutic drug monitoring was also undertaken in White-backed, Egyptian (Neophron pernopterus) and one Lappet Faced vulture (Torgos tracheliotos). In all these species, meloxicam was characterized by a short half-life of elimination. The rapid metabolism of meloxicam in combination with a short duration of effect in the studied species Gyps vultures shown in this study makes it unlikely that the drug could accumulate. This confirms the safety of repeated exposure to meloxicam in vultures of this genus.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Falconiformes/metabolismo , Tiazinas/farmacocinética , Tiazóis/farmacocinética , Administração Oral , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/sangue , Área Sob a Curva , Bovinos , Resíduos de Drogas , Cadeia Alimentar , Injeções Intramusculares/veterinária , Meloxicam , Tiazinas/administração & dosagem , Tiazinas/sangue , Tiazóis/administração & dosagem , Tiazóis/sangue
16.
Cell Death Differ ; 14(9): 1605-16, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17541428

RESUMO

Melanoma cells depend on sustained proteasomal function for survival. However, bortezomib, the first proteasome inhibitor in clinical use, is not sufficient to improve the poor prognosis of metastatic melanoma patients. Since the proteasome is also expressed in all normal cell compartments, it is unclear how to enhance the efficacy of bortezomib without exacerbating secondary toxicities. Here, we present pharmacological and genetic analyses of mechanisms of resistance to proteasome inhibition. We focused on Bcl-2, Bcl-x(L) and Mcl-1 as main antiapoptotic factors associated with melanoma progression. Despite an efficient blockage of the proteasome, bortezomib could not counteract the intrinsically high levels of Bcl-2 and Bcl-x(L) in melanoma cells. Moreover, Mcl-1 was only downregulated at late time points after treatment. Based on these results, a combination treatment including (-)-gossypol, an inhibitor of Mcl-1/Bcl-2/Bcl-x(L), was designed and proven effective in vivo. Using a specific RNA interference approach, the survival of bortezomib-treated melanoma cells was found to rely primarily on Mcl-1, and to a lesser extent on Bcl-x(L) (but not on Bcl-2). Importantly, neither Mcl-1 nor Bcl-x(L) inactivation affected the viability of normal melanocytes. This hierarchical requirement of Bcl-2 family members for the maintenance of normal and malignant cells offers a therapeutic window to overcome melanoma chemoresistance in a tumor cell-selective manner.


Assuntos
Ácidos Borônicos/farmacologia , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/metabolismo , Inibidores de Proteassoma , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirazinas/farmacologia , Animais , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/fisiologia , Ácidos Borônicos/metabolismo , Bortezomib , Caspases/metabolismo , Linhagem Celular Tumoral , Gossipol/metabolismo , Gossipol/farmacologia , Humanos , Melanoma Experimental/imunologia , Camundongos , Transplante de Neoplasias , Inibidores de Proteases/metabolismo , Inibidores de Proteases/farmacologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Pirazinas/metabolismo , Transplante Heterólogo
17.
Vox Sang ; 91(2): 162-73, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16907878

RESUMO

BACKGROUND AND OBJECTIVES: The safety of chronic intensive donor plasmapheresis has not been determined in large prospective studies examining dropout rates, dropout reasons and predictors of withdrawals. MATERIALS AND METHODS: Twenty-one plasma centres recruited 3783 donors who were switched from a moderate to an intensive plasmapheresis programme and observed over a 3-year period. Individuals weighing < 70 kg and > or = 70 kg donated 750 ml and 850 ml of plasma per session, respectively. The maximum of annual donations was limited to 60. Total serum protein (TSP) and haemoglobin (Hb) or haematocrit (Hct) were determined at each donation, and immunoglobulin G (IgG) at every fifth donation. Dropout rates, dropout reasons and potential predictors of withdrawal were analysed. RESULTS: Dropouts were predominantly due to socioeconomic (49.2% of all donors) or medical reasons not related to plasma donations (10.4% of all donors). Sixteen per cent of donors dropped out when IgG, TSP or Hb levels fell below threshold values. Severe clinical adverse events related to plasmapheresis were observed in five subjects. The incidence in severe cardiovascular diseases was lower in donors than in the general population. The risk factors that led to dropping out as a result of low IgG, TSP or Hb levels included younger age, female gender, low initial IgG levels and a high donation frequency. Neither body weight nor the amounts of plasma donated per kilogram of body weight per session were associated with ceasing due to medical reasons, whether related or unrelated to plasma donations. Females and males within the respective lowest body weight category were not at higher risk of dropping out. CONCLUSION: Long-term intensive donor plasmapheresis under conditions investigated in this study is safe. All donors weighing > or = 70 kg are safely able to donate 850 ml of plasma in each session up to 60 times per year, provided that they are carefully monitored.


Assuntos
Doadores de Sangue , Pacientes Desistentes do Tratamento , Plasmaferese/efeitos adversos , Adulto , Doadores de Sangue/psicologia , Peso Corporal , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Plasmaferese/métodos , Modelos de Riscos Proporcionais , Estudos Prospectivos , Risco , Fatores Socioeconômicos , Análise de Sobrevida , Suíça , Fatores de Tempo
18.
Water Sci Technol ; 45(9): 87-94, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12079128

RESUMO

Seven regions with coastal eutrophication problems in the Baltic Sea, including the Kattegat, constitute the BERNET project (Baltic Eutrophication Regional Network). To counteract eutrophication and associated severe biological conditions the countries around this large brackish water body must all cooperate. The regions are characterized by large differences in land use, e.g. agricultural intensity, and losses of retention capacity in the catchments due to wetland reclamation. Initially it has been necessary to identify nutrient sources--especially nitrogen--and technical, economical and even administrative obstacles to initiate eutrophication management measures. Nitrogen retention in different types of wetlands in the Baltic Sea Region has been analysed. The wetlands generally have a positive effect on reduced nitrogen transport to aquatic environments and it is generally accepted that measures leading to decreased losses of nutrients to the aquatic environment must be combined with measures leading to increased retention of nutrients in catchments. Data analysed in the BERNET project show that the potential for such a measure is large. Therefore, conservation and restoration initiatives for wetlands is an essential part of the work in the BERNET project. Wetlands have been drained or totally eliminated due to intensive agriculture in some regions while large scale rehabilitation of wetlands occurs in regions with less intensive agriculture. Based on land use data from the seven regions, the working group for wetland management within the BERNET project has identified the possible use of wetlands as building blocks as a contribution to the management of the Baltic Sea eutrophication. Several recommendations are presented on the wise use of existing and constructed wetlands for water quality management in relation to non-point nutrient pollution.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Eutrofização , Poluição da Água/prevenção & controle , Agricultura , Países Bálticos , Filtração , Cooperação Internacional , Nitrogênio/análise , Movimentos da Água
19.
Breast Cancer Res Treat ; 73(2): 161-75, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12088118

RESUMO

PURPOSE: This trial was designed to demonstrate equivalence between droloxifene 40 mg/d and tamoxifen 20 mg/d as first-line treatment in pre- and post-menopausal women with ER+ and/or PgR+ advanced breast cancer based on time to disease progression and tumor response. MATERIALS AND METHODS: One thousand three hundred fifty four women with measurable disease, previously untreated by hormonal or chemotherapy for advanced or recurrent breast cancer, were enrolled by 179 institutions in 35 countries. Patients were stratified at baseline for menopausal status. Patients receiving adjuvant hormonal therapy within I year were excluded. All patients gave written informed consent, were randomized to 40mg droloxifene or 20 mg tamoxifen daily as single-agent therapy and underwent tumor assessment every 3 months. A central committee reviewed digitized images for all cases of tumor progression or objective response. RESULTS: The hazard ratio (droloxifene/tamoxifen) for the primary endpoint, time to disease progression, was 1.287 favoring tamoxifen (95% C.I.: 1.114-1.487; p <.001). The objective response rate (CR+PR) was 22.4% for droloxifene and 28.6% for tamoxifen (p = .02). Tamoxifen was superior to droloxifene overall, among both pre- and postmenopausal patients and among patients < or =65 years; there was no difference among women >65 years. The hazard ratio for all-cause mortality was 0.871 (95% C.I.: 0.672-1.129; p = .29), favoring droloxifene but not statistically significant. CONCLUSIONS: Droloxifene was significantly less effective than tamoxifen overall and particularly among women under 65 years. Tamoxifen and droloxifene were both less effective in pre-menopausal women with receptor-positive disease compared to post-menopausal women. Further clinical development of droloxifene was stopped.


Assuntos
Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Antagonistas de Estrogênios/uso terapêutico , Tamoxifeno/análogos & derivados , Tamoxifeno/uso terapêutico , Fatores Etários , Idoso , Neoplasias da Mama/patologia , Progressão da Doença , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Tamoxifeno/administração & dosagem , Tamoxifeno/agonistas , Equivalência Terapêutica , Resultado do Tratamento
20.
Nephron ; 85(1): 41-9, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10773754

RESUMO

Lipoprotein(a) [Lp(a)] excess combined with hyperhomocysteinaemia and hyperfibrinogenaemia may contribute to the high incidence of vascular diseases in dialysis patients. This study is aimed at investigating the role of free apolipoprotein(a) [fapo(a)] in renal patients. We have been able to show that, as compared with controls (0.53 mg/l), the median serum concentrations of fapo(a) in patients with nephrotic syndrome (2.58 mg/l) and with peritoneal dialysis (3. 40 mg/l) were strongly elevated (5- to 7-fold), while the fapo(a) levels in patients undergoing haemodialyis (1.02 mg/l) and after renal transplantation (0.90 mg/l) were about doubled. The observed differences in fapo(a) levels indicate that several mechanisms may increase the level of fapo(a), i.e., reduced renal clearance, enhanced hepatic synthesis, or homocysteine releasing apolipoprotein(a) from Lp(a). In the study collective, the median total homocysteine levels were significantly elevated in all patient groups, stronger in patients on haemodialysis (31.4 micromol/l) and peritoneal dialysis (31.2 micromol/l) than in patients with nephrotic syndrome (19.7 micromol/l) and after renal transplantation (19.5 micromol/l). In transplant patients with adequate renal function and without other apolipoprotein(a)-increasing factors, fapo(a) was significantly increased when total homocysteine exceeded 22 micromol/l. In conclusion, our findings let us presume that an increased fapo(a) level in renal patients possibly could be one of the reasons contributing to the high incidence of vascular diseases in these patients, because fapo(a) not covalently linked with Lp(a) is even more easily able to inhibit the fibrinolytic system than the complete Lp(a). These preliminary results have to be confirmed by further investigations.


Assuntos
Apolipoproteínas A/sangue , Homocisteína/sangue , Falência Renal Crônica/sangue , Lipoproteína(a)/sangue , Síndrome Nefrótica/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Hiper-Homocisteinemia/sangue , Falência Renal Crônica/cirurgia , Falência Renal Crônica/terapia , Transplante de Rim , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Síndrome Nefrótica/cirurgia , Síndrome Nefrótica/terapia , Diálise Peritoneal , Diálise Renal
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