The panbiogeograpy of hagfishes: a reply to Briggs's anachronistic criticism

Briggs's (2009) criticisms of Cavalcanti & Gallo's (2008) panbiogeographical study of hagfishes are shown to be either supportive of the criticized paper's main findings or trivial, arising from an incomplete understanding of the panbiogeographical method and synthesis and of methodological prejudice against this conceptual framework.     

Photosensitizers and antioxidants: a way to new drugs?

Photodynamic therapy (PDT) is a relatively new modality of treatment of diseases involving uncontrolled cell proliferation. It is based on the production of reactive species upon illumination of a photosensitizer in the presence of oxygen. Antioxidants are primarily reducing agents prone to scavenge reactive species in one way or another. Their presence in photodynamic reactions usually reduces the efficacy of PDT. Some antioxidants like ascorbic acid, alpha-tocopherol or butyl-4-hydroxyanisole, however, when added to cells at adequate concentrations may enhance the photodamaging activity of PDT. The presence of transition metals and precise timing of antioxidant administration may also be important factors in increasing the efficacy of PDT. Antioxidant carrier sensitizers have been designed, synthesised and tested for their antibacterial PDT activity. The promising results raise the question whether the introduction of antioxidant moieties into sensitizer molecules would lead to the synthesis of highly effective new drugs.     

Exposure to ionizing radiation during pregnancy: perception of teratogenic risk and outcome

We quantified the perception of teratogenic risk in women attending the Motherisk program for counseling about diagnostic radiation in pregnancy (n = 50) and compared it with a control group of women exposed to nonteratogenic drugs and chemicals (n = 48). Before receiving known information about the specific exposure, women exposed to radiation assigned themselves a significantly higher teratogenic risk compared with the control group (25.5 +/- 4.3% versus 15.7 +/- 3.0% for major malformations, P less than 0.01). The post-consultation perception of teratogenic risk did not differ between the two groups. Special consideration and attention should be given when counseling pregnant women exposed to low-dose ionizing radiation, as their misperception of teratogenic risk may lead them to unnecessary termination of their pregnancy.     

Topological virtual screening: a way to find new anticonvulsant drugs from chemical diversity

A topological virtual screening (tvs) test is presented, which is capable of identifying new drug leaders with anticonvulsant activity. Molecular structures of both anticonvulsant-active and non active compounds, extracted from the Merck Index database, were represented using topological indexes. By means of the application of a linear discriminant analysis to both sets of structures, a topological anticonvulsant model (tam) was obtained, which defines a connectivity function. On the basis of this model, 41 new structures with anticonvulsant activity have been identified by a topological virtual screening.     

A rare motive for genetic counseling: the risk of leukemia: apropos of a familial form

Authors report one family with three cases of myeloblastic acute leukaemia in three generations. In this family, without chromosomal abnormalities (the only one possible laboratory examination), the risk is certainly increased, but it remains, fortunately, low.     

Just a hypothesis: a reply to Hanski

Hanski's critique of the habitat amount hypothesis (Hanski, 2015, Journal of Biogeography, 42 , 989–993) does not actually constitute a test of the hypothesis, but rather a series of arguments for why he suspects that it is not correct. But the habitat amount hypothesis is exactly that – a hypothesis. It will remain ‘just’ a hypothesis until it has been rigorously tested against empirical data. To facilitate such testing, in Fahrig (2013, Journal of Biogeography, 40 , 1649–1663) I presented specific, testable predictions of the hypothesis. Here, I reiterate the main tests needed, in the hope that some readers will be encouraged to carry them out. I appreciate this opportunity to emphasize that the habitat amount hypothesis needs to be tested against empirical data, and I look forward to seeing the results of such tests.     

Maternal factors affecting teratogenic response: a need for assessment.

A review of current literature suggests that maternal nutritional status can be an important modulator of the developmental toxicity of a number of agents in the environment. While the provision of multivitamin/multimineral supplements during the periconceptional period is often associated with improved pregnancy outcome, it has been difficult to identify specific nutrient deficiencies as causative factors of abnormal development in humans. One explanation for this is that nutrient deficiencies can arise through a number of means in addition to a simple dietary deficit of the nutrient. The hypothesis is proposed that one mechanism contributing to the embryotoxicity of a diverse group of insults is an alteration in the metabolism of select nutrients. Evidence is presented that zinc is one nutrient whose metabolism can be markedly influenced by a variety of insults. One consequence of this alteration can be a reduction in embryonic zinc uptake, the development of embryonic zinc deficiency and abnormal development.