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1.
Homeopathy ; 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866048

RESUMO

BACKGROUND: Previously we developed a test system which yielded highly significant evidence for specific effects of a Stannum metallicum 30x preparation in a multi-center replication trial. This test system is based on cress seed germination in homeopathic or control samples, CuCl2 crystallization of the cress extract, and subsequent digital textural image analysis of the resulting crystallization patterns. OBJECTIVES: The current study aimed to investigate whether three novel outcome parameters could further corroborate and possibly characterize the specific effects of Stannum metallicum 30x. METHODS: To this end, (1) cress seedling length, (2) a second texture analysis parameter, entropy and (3) the local connected fractal dimension (LCFD) of crystallization patterns as a measure of complexity were considered. The stability of the experimental setup was monitored throughout the entire investigation with systematic negative control (SNC) experiments. RESULTS: Cress length and entropy revealed a time-modulated potency treatment effect, in the absence of a significant main treatment effect. This indicated that the effect of the potency treatment varied significantly across the different experimental days. LCFD yielded a highly significant potency treatment effect. In addition, a significant interaction of treatment with experimental day seems to indicate a modulation of this effect. No significant effects were observed in any of the evaluations of the SNC experiments, indicative of a stable experimental setup and a reliable and specific treatment effect. Neither significant nor strong correlations were found between the four parameters, indicating that they reflect different effects of Stannum metallicum 30x on the organism treated. CONCLUSION: This quadruple characterization of the biological effects of Stannum metallicum 30x provides an unprecedented opportunity for basic homeopathy research into, among others, the presumed specificity of homeopathic preparations.

2.
Homeopathy ; 107(2): 115-129, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29621812

RESUMO

BACKGROUND: Plant-based test systems have been described as a useful tool for investigating possible effects of homeopathic preparations. The last reviews of this research field were published in 2009/2011. Due to recent developments in the field, an update is warranted. Publications on plant-based test systems were analysed with regard to publication quality, reproducibility and potential for further research. METHODS: A literature search was conducted in online databases and specific journals, including publications from 2008 to 2017 dealing with plant-based test systems in homeopathic basic research. To be included, they had to contain statistical analysis and fulfil quality criteria according to a pre-defined manuscript information score (MIS). Publications scoring at least 5 points (maximum 10 points) were assumed to be adequate. They were analysed for the use of adequate controls, outcome and reproducibility. RESULTS: Seventy-four publications on plant-based test systems were found. Thirty-nine publications were either abstracts or proceedings of conferences and were excluded. From the remaining 35 publications, 26 reached a score of 5 or higher in the MIS. Adequate controls were used in 13 of these publications. All of them described specific effects of homeopathic preparations. The publication quality still varied: a substantial number of publications (23%) did not adequately document the methods used. Four reported on replication trials. One replication trial found effects of homeopathic preparations comparable to the original study. Three replication trials failed to confirm the original study but identified possible external influencing factors. Five publications described novel plant-based test systems. Eight trials used systematic negative control experiments to document test system stability. CONCLUSIONS: Regarding research design, future trials should implement adequate controls to identify specific effects of homeopathic preparations and include systematic negative control experiments. Further external and internal replication trials, and control of influencing factors, are needed to verify results. Standardised test systems should be developed.


Assuntos
Homeopatia/métodos , Extratos Vegetais/química , Plantas Medicinais , Humanos , Materia Medica/química , Projetos de Pesquisa , Soluções
3.
PLoS One ; 16(3): e0248124, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33720965

RESUMO

There is an increasing interest in a systemic approach to food quality. From this perspective, the copper chloride crystallization method is an interesting asset as it enables an estimation of a sample's 'resilience' in response to controlled degradation. In previous studies, we showed that an ISO-standardized visual evaluation panel could correctly rank crystallization images of diverse agricultural products according to their degree of induced degradation. In this paper we examined the role of contextual sensitivity herein, with the aim to further improve the visual evaluation. To this end, we compared subjects' performance in ranking tests, while primed according to two perceptional strategies (levels: analytical vs. kinesthetic engagement), according to a within-subject design. The ranking test consisted out of wheat and rocket lettuce crystallization images, exhibiting four levels of induced degradation. The perceptual strategy imbuing kinesthetic engagement improved the performance of the ranking test in both samples tested. To the best of our knowledge, this is the first report on the training and application of such a perceptual strategy in visual evaluation.


Assuntos
Análise de Alimentos , Qualidade dos Alimentos , Cristalização , Grão Comestível/química , Análise de Alimentos/métodos , Humanos , Lactuca/química , Triticum/química , Percepção Visual
4.
Heliyon ; 5(1): e01102, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30627687

RESUMO

The overall structure of dihydrate cupric chloride (CuCl2 * 2H2O) crystallization patterns in the presence of bovine serum albumin (BSA) in a Petri dish is influenced by dewetting. The dewetting behavior, which can be either before or after initial CuCl2 nucleation, depends on the amount of CuCl2 and BSA in the Petri dish. We postulate that the concentration and/or temperature gradient area in the dish, which is built up during the evaporation process, coincides with the location where dewetting predominantly starts. This hypothesis could be supported by measurements of the CuCl2 coverage of the Petri dish. During the evaporation the height of the meniscus at the rim of the Petri dish recedes in favor of the central Petri dish area. This could not be explained by the above mentioned hypothesis.

5.
J Colloid Interface Sci ; 344(2): 556-62, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20116068

RESUMO

The overall structure of the crystallization results of dihydrate cupric chloride with additives in a petri dish is affected by the duration between the beginning of the evaporation and the start of the crystallization. Experiments done with polyvinylpyrrolidone and freeze-dried carrot as additive are compared with those of the additive free case. The dependency of dewetting on the dihydrate cupric chloride amount is discussed in terms of depletion of the solution and the surface tension properties of the system. The possible influence of the depletion is depending on the moment the crystallization starts. This is defined by the size of the evaporated area on the dish.


Assuntos
Cobre/química , Daucus carota/química , Povidona/química , Água/química , Cristalização , Tamanho da Partícula , Soluções , Propriedades de Superfície , Volatilização
6.
Int J Cancer ; 100(3): 309-17, 2002 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-12115546

RESUMO

In a subset of endocrine therapy-resistant prostate cancers, amino acid substitutions H874Y, T877A and T877S, which broaden ligand specificity of the ligand binding domain (LBD) of the androgen receptor (AR), have been detected. To increase our knowledge of the role of amino acid substitutions at these specific positions in prostate cancer, codons 874 and 877 were subjected to random mutagenesis. AR mutants were screened in a yeast readout system for responsiveness to 5 alpha-dihydrotestosterone, progesterone and dehydroepiandrosterone. At position 874, only the histidine to tyrosine substitution could broaden AR ligand specificity. At position 877, 4 ligand specificity broadening substitutions were found: T877A, T877S, T877C and T877G. The latter 2 were not found in prostate cancer. The AR mutants were tested in mammalian (Hep3B) cells for responsiveness to 13 different ligands. All mutants displayed their own ligand specificity spectrum. Importantly, AR(H874Y) and AR(T877A) could be activated by cortisol. According to the 3-dimensional structure of the AR LBD, T877 interacts directly with the 17 beta-hydroxyl group of androgens. All amino acid substitutions identified at position 877 had smaller side chains than the threonine in the wild-type receptor, indicating that increased space in the ligand binding pocket is important in broadened ligand specificity. Because H874 does not interact directly with the ligand, its substitution by a tyrosine is expected to change the ligand binding pocket conformation indirectly. For T877C and T877G substitutions, 2-point mutations are required, and for H874Y, T877A and T877S substitutions, only a 1-point mutation is sufficient. This most likely explains that the latter 3 have been found in prostate cancer.


Assuntos
Androgênios/farmacologia , Códon , Glucocorticoides/farmacologia , Mutação , Neoplasias da Próstata/genética , Receptores Androgênicos/genética , Sítios de Ligação , Humanos , Ligantes , Masculino , Receptores Androgênicos/química , Receptores Androgênicos/metabolismo , Transcrição Gênica
7.
Eur J Biochem ; 269(23): 5780-91, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12444966

RESUMO

The N-terminal domain (NTD) and the ligand-binding domain (LBD) of the androgen receptor (AR) exhibit a ligand-dependent interaction (N/C interaction). Amino acids 3-36 in the NTD (AR3-36) play a dominant role in this interaction. Previously, it has been shown that a PhixxPhiPhi motif in AR3-36, 23FxxLF27, is essential for LBD interaction. We demonstrate in the current study that AR3-36 can be subdivided into two functionally distinct fragments: AR3-13 and AR16-36. AR3-13 does not directly interact with the AR LBD, but rather contributes to the transactivation function of the AR.NTD-AR.LBD complex. AR16-36, encompassing the 23FxxLF27 motif, is predicted to fold into a long amphipathic alpha-helix. A second PhixxPhiPhi candidate protein interaction motif within the helical structure, 30VREVI34, shows no affinity to the LBD. Within AR16-36, amino acid residues in and flanking the 23FxxLF27 motif are demonstrated to modulate N/C interaction. Substitution of Q24 and N25 by alanine residues enhances N/C interaction. Substitution of amino acids flanking the 23FxxLF27 motif by alanines are inhibitory to LBD interaction.


Assuntos
Motivos de Aminoácidos , Aminoácidos/metabolismo , Receptores Androgênicos/metabolismo , Sequência de Aminoácidos , Aminoácidos/química , Animais , Sequência de Bases , Sítios de Ligação , Células CHO , Cricetinae , Primers do DNA , Ligantes , Receptores Androgênicos/química , Homologia de Sequência de Aminoácidos
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