scholarly journals Bioactivity – Symphony or Cacophony?

Author(s):  
Brian W Darvell

In the pursuit of better treatments, the concept of a chemically-active material, responding to local conditions by causing reactions, or reacting to produce substances that are deemed beneficial, seems laudable. Ultimately, the goal appears to be to recruit natural biological processes such that a natural ‘repair’ is effected. This goal seems to be the reason for prefixing “bio-“ to many terms with a view to advertising the desire, yet without presenting evidence that it has occurred, or indeed that it is capable of occurring, relying instead on non-biological processes to justify the claims. The dogma is such that all work where local ‘responsive’ chemistry is involved must receive the label “bioactive” to legitimize and promote. Nevertheless, the primary evidence adduced is flawed, and the claim must fail. A rethink to restore scientific sense and confidence in the endeavour is essential if real progress is to be made.

Prosthesis ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 75-84
Author(s):  
Brian W Darvell

In the pursuit of better treatments, the concept of a chemically-active material, responding to local conditions by causing reactions, or reacting to produce substances that are deemed beneficial, seems laudable. Ultimately, the goal appears to be to recruit natural biological processes such that a natural ‘repair’ is effected. This goal seems to be the reason for prefixing “bio-” to many terms with a view to advertising the desire, yet without presenting evidence that it has occurred, or indeed that it is capable of occurring, relying instead on non-biological processes to justify the claims. The dogma is such that all work where local ‘responsive’ chemistry is involved must receive the label “bioactive” to legitimize and promote. Nevertheless, the primary evidence adduced is flawed, and the claim must fail. A rethink to restore scientific sense and confidence in the endeavour is essential if real progress is to be made.


Parasitology ◽  
2017 ◽  
Vol 145 (1) ◽  
pp. 101-110 ◽  
Author(s):  
LAITH YAKOB ◽  
ALUN L. LLOYD ◽  
ROWLAND R. KAO ◽  
HEATHER M. FERGUSON ◽  
PATRICK M. BROCK ◽  
...  

SUMMARYPlasmodium knowlesi is increasingly recognized as a major cause of malaria in Southeast Asia. Anopheles leucosphyrous group mosquitoes transmit the parasite and natural hosts include long-tailed and pig-tailed macaques. Despite early laboratory experiments demonstrating successful passage of infection between humans, the true role that humans play in P. knowlesi epidemiology remains unclear. The threat posed by its introduction into immunologically naïve populations is unknown despite being a public health priority for this region. A two-host species mathematical model was constructed to analyse this threat. Global sensitivity analysis using Monte Carlo methods highlighted the biological processes of greatest influence to transmission. These included parameters known to be influential in classic mosquito-borne disease models (e.g. vector longevity); however, interesting ecological components that are specific to this system were also highlighted: while local vectors likely have intrinsic preferences for certain host species, how plastic these preferences are, and how this is shaped by local conditions, are key determinants of parasite transmission potential. Invasion analysis demonstrates that this behavioural plasticity can qualitatively impact the probability of an epidemic sparked by imported infection. Identifying key vector sub/species and studying their biting behaviours constitute important next steps before models can better assist in strategizing disease control.


Author(s):  
Leslie M. Loew

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.


Author(s):  
Jan-Olle Malm ◽  
Jan-Olov Bovin

Understanding of catalytic processes requires detailed knowledge of the catalyst. As heterogeneous catalysis is a surface phenomena the understanding of the atomic surface structure of both the active material and the support material is of utmost importance. This work is a high resolution electron microscopy (HREM) study of different phases found in a used automobile catalytic converter.The high resolution micrographs were obtained with a JEM-4000EX working with a structural resolution better than 0.17 nm and equipped with a Gatan 622 TV-camera with an image intensifier. Some work (e.g. EDS-analysis and diffraction) was done with a JEM-2000FX equipped with a Link AN10000 EDX spectrometer. The catalytic converter in this study has been used under normal driving conditions for several years and has also been poisoned by using leaded fuel. To prepare the sample, parts of the monolith were crushed, dispersed in methanol and a drop of the dispersion was placed on the holey carbon grid.


2003 ◽  
Vol 39 ◽  
pp. 11-24 ◽  
Author(s):  
Justin V McCarthy

Apoptosis is an evolutionarily conserved process used by multicellular organisms to developmentally regulate cell number or to eliminate cells that are potentially detrimental to the organism. The large diversity of regulators of apoptosis in mammalian cells and their numerous interactions complicate the analysis of their individual functions, particularly in development. The remarkable conservation of apoptotic mechanisms across species has allowed the genetic pathways of apoptosis determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster, to act as models for understanding the biology of apoptosis in mammalian cells. Though many components of the apoptotic pathway are conserved between species, the use of additional model organisms has revealed several important differences and supports the use of model organisms in deciphering complex biological processes such as apoptosis.


1990 ◽  
Vol 78 (1) ◽  
pp. 1-1
Author(s):  
M. J. Brown

From this issue, Clinical Science will increase its page numbers from an average of 112 to 128 per monthly issue. This welcome change — equivalent to at least two manuscripts — has been ‘forced’ on us by the increasing pressure on space; this has led to an undesirable increase in the delay between acceptance and publication, and to a fall in the proportion of submitted manuscripts we have been able to accept. The change in page numbers will instead permit us now to return to our exceptionally short interval between acceptance and publication of 3–4 months; and at the same time we shall be able not only to accept (as now) those papers requiring little or no revision, but also to offer hope to some of those papers which have raised our interest but come to grief in review because of a major but remediable problem. Our view, doubtless unoriginal, has been that the review process, which is unusually thorough for Clinical Science, involving a specialist editor and two external referees, is most constructive when it helps the evolution of a good paper from an interesting piece of research. Traditionally, the papers in Clinical Science have represented some areas of research more than others. However, this has reflected entirely the pattern of papers submitted to us, rather than any selective interest of the Editorial Board, which numbers up to 35 scientists covering most areas of medical research. Arguably, after the explosion during the last decade of specialist journals, the general journal can look forward to a renaissance in the 1990s, as scientists in apparently different specialities discover that they are interested in the same substances, asking similar questions and developing techniques of mutual benefit to answer these questions. This situation arises from the trend, even among clinical scientists, to recognize the power of research based at the cellular and molecular level to achieve real progress, and at this level the concept of organ-based specialism breaks down. It is perhaps ironic that this journal, for a short while at the end of the 1970s, adopted — and then discarded — the name of Clinical Science and Molecular Medicine, since this title perfectly represents the direction in which clinical science, and therefore Clinical Science, is now progressing.


2001 ◽  
Vol 6 (3) ◽  
pp. 172-176 ◽  
Author(s):  
Lawrence A. Pervin

David Magnusson has been the most articulate spokesperson for a holistic, systems approach to personality. This paper considers three concepts relevant to a dynamic systems approach to personality: dynamics, systems, and levels. Some of the history of a dynamic view is traced, leading to an emphasis on the need for stressing the interplay among goals. Concepts such as multidetermination, equipotentiality, and equifinality are shown to be important aspects of a systems approach. Finally, attention is drawn to the question of levels of description, analysis, and explanation in a theory of personality. The importance of the issue is emphasized in relation to recent advances in our understanding of biological processes. Integrating such advances into a theory of personality while avoiding the danger of reductionism is a challenge for the future.


1999 ◽  
Vol 82 (08) ◽  
pp. 305-311 ◽  
Author(s):  
Yuri Koshelnick ◽  
Monika Ehart ◽  
Hannes Stockinger ◽  
Bernd Binder

IntroductionThe urokinase-urokinase receptor (u-PA-u-PAR) system seems to play a crucial role in a number of biological processes, including local fibrinolysis, tumor invasion, angiogenesis, neointima and atherosclerotic plaque formation, inflammation, and matrix remodeling during wound healing and development.1-6 Binding of urokinase to its specific receptor provides cells with a localized proteolytic potential. It stimulates conversion of cell surface-bound plasminogen into active plasmin, which, in turn, is required for proteolytic degradation of basement membrane components, including fibronectin, collagen, laminin, and proteoglycan core proteins.7 Moreover, plasmin activates other matrix-degrading enzymes, such as matrix metalloproteinases.8 Overexpression of u-PA/u-PAR correlates with tumor invasion and metastasis formation,9-13 while reduction of cell-surface bound u-PA and inhibition of u-PAR expression leads to a significant decrease of invasive and metastatic activity.14 Specific antagonists that suppress binding of u-PA to u-PAR have been shown to inhibit cell-surface plasminogen activation, tumor growth, and angiogenesis both in vitro and in vivo models.15,16 Independently of its proteolytic activity, u-PA is implicated in many biological processes that seem to require u-PAR-mediated intracellular signal transduction, such as proliferation, chemotactic movement and adhesion, migration, and differentiation.17 Data obtained in the late 1980s indicated that u-PA not only provides cells with local proteolytic activity, but might also be capable of transducing signals to the cell.18-22 At that time, however, the u-PAR has just been isolated, cloned, and identified as a glycosylphosphatidylinositol (GPI)-linked protein and not a transmembrane protein. Signaling via the u-PAR was, therefore, regarded as being unlikely, and the effects of u-PA on cell proliferation18-22 were thought to be mediated by proteolytic activation of latent growth factors. The assumption of direct signaling via u-PAR was, in fact, considered controversial, until about 10 years later when a physical association between u-PAR and signaling proteins was found.23 From this report on, several proteins associated with u-PAR have been identified. Now, u-PAR seems to be part of a large “signalosome” associated and interacting with several proteins on both the outside and inside of the cell.


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