Cutaneous horns: are these lesions as innocent as they seem to be?

Background  

Cutaneous horns (cornu cutaneum) are uncommon lesions consisting of keratotic material resembling that of an animal horn. Cutaneous horn may arise from a wide range of the epidermal lesions, which may be benign, premalignant or malignant.     

Are the effects of different enrichment designs on the physiology and behaviour of DBA/2 mice consistent?

Environmental enrichment is intended to improve the well-being of laboratory animals. Although many researchers have indicated that environmental enrichment may enhance animal well-being, there is some evidence that enrichment differs in its effects on physiology and behaviour between species and strains. The present study focuses on the effects of different enrichment designs on the physiology and behaviour of male and female DBA/2 mice. A total of 48 DBA/2J mice, 24 males and 24 females were used for this experiment. Upon arrival at about 3 weeks of age, the animals were randomly allotted to three experimental groups: NE, non-enrichment; E1, enriched with nest box, wooden climbing bar and nest material according to Scharmann (1993); E2, enriched with horizontal and vertical dividers, modified from Haemisch and G?rtner (1994). Same-sex groups of four mice were housed for 12 weeks in type III Makrolon cages with (E1 or E2) or without (NE) enrichment objects. Behavioural performance (Open Field, Food Drive and Elevated Plus Maze tests) and physiological traits (haematological variables, body weight and organ weights, corticosterone and thyroxine levels) were measured. This study observed that enrichment had significant effects on the mean values of body weight (females), Open Field and Food Drive tests. The most significant housing differences were found between the E2 and NE/E1 groups. Furthermore, sex differences in the NE, E1 and E2 groups were not consistent for several variables (growth rate, relative weights of spleen, kidney and heart, Food Drive and Elevated Plus Maze behavioural performance). There was often a higher coefficient of variation (CV) in the E1 and E2 groups as compared to the NE group, chiefly in physiological traits and in the Open Field and Food Drive tests. The results of this study indicate, that the effects of enrichment designs used in the present study are not consistent, but vary according to sex and the variable studied.     

Determination of the post mortem interval in skeletal remains by the comparative use of different physico-chemical methods: Are they reliable as an alternative to 14C?

The determination of the post-mortem interval (PMI) of skeletal remains is a challenging aspect in the forensic field. Previous studies focused their attention on different macroscopic and morphological aspects but a thorough and complete evaluation of the potential of chemical and physical analyses in this field of research has not been performed. In addition to luminol test and Oxford histology index (OHI) reported in a recent paper, widely spread and accessible methods based on physical aspect and chemical characteristics of skeletal remains have been investigated as potential alternatives to dating by determination of ¹⁴C.The investigation was performed on a total of 24 archeological and forensic bone samples with known PMI, with inductively coupled plasma optical emission spectrometer (ICP-OES), inductively coupled plasma quadruple mass spectrometry (ICP-MS), Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray analysis (EDX), powder X-ray diffraction analysis (XRPD) and scanning electron microscopy (SEM). Finally, the feasibility of such alternative methods was discussed. Some results such as carbonates/phosphates ratio from FT-IR, the amounts of organic and inorganic matter by EDX, crystallite sizes with XRPD, and surface morphology obtained by SEM, showed significant trends along with PMI. Though, from a chemical point of view cut-off values and gold-standard methods still present challenges, and rather different techniques together can provide useful information toward the assessment of the PMI of skeletal remains. It is however clear that in a hypothetical flowchart those methods may be placed practically at the same level and a choice should always consider the evaluation of results by each technique, execution times and a costs/benefits relationship.     

Whither life? Conjectures on the future evolution of biochemistry

Life has existed on the Earth for approximately four billion years. The sheer depth of evolutionary time, and the diversity of extant species, makes it tempting to assume that all the key biochemical innovations underpinning life have already happened. But we are only a little over halfway through the trajectory of life on our planet. In this Opinion piece, we argue: (i) that sufficient time remains for the evolution of new processes at the heart of metabolic biochemistry and (ii) that synthetic biology is providing predictive insights into the nature of these innovations. By way of example, we focus on engineered solutions to existing inefficiencies in energy generation, and on the complex, synthetic regulatory circuits that are currently being implemented.     

Are mAbs different?

Apart from the nifty science behind their development, are monoclonal antibodies (mAbs) different than other new technologies? As highlighted by Cohen and Wilson in their interesting new paper, mAbs are distinctive from most traditional pharmaceuticals in some ways: their relatively high prices; their high costs of development; their mode of administration; the fact that, unlike many other drugs, they offer disease modification not simply symptomatic relief; the frequency of supplemental indications and off-label use – much of it recognized in drug compendia and reimbursable; and the lack of a clear pathway for their generic substitution.     

Three conditions for the evolution of eusociality: Are they sufficient?

Summary I hypothesize that three conditions, (1) food-shelter coincidence, (2) strong selection for defense, and (3) ability to defend, are sufficient, although not necessary, for the evolution of eusociality in group-living animals. Reasons for this association between ecology and eusociality include extremely high value of the habitat, possibilities for habitat inheritance, high relatedness in claustral situations, self-sufficiency of juveniles, greater ability of workers to reproduce, and trade-offs between defensive ability and dispersal.     

Oxygenation of the phenylhalocarbenes. Are they spin-allowed or spin-forbidden reactions?

Oxygenation mechanisms of phenylhalocarbenes in vacuum are investigated through the use of density functional theory and CASSCF-PT2 approaches. Reactions with both substituted and unsubstituted phenylhalocarbenes are strongly exothermic. The reactions with nitrosubstituted halocarbenes are predicted to be spin allowed due to the practical degeneracy of the singlet and triplet carbene states. Conversely, for the unsubstituted compounds, the equilibrium between the triplet carbene and (3)O(2) requires a previous singlet-triplet state crossing. The large spin-orbit coupling at this crossing suggests a rather efficient tunneling rate. This would help to explain why the rate constant in solution in these cases is only one order of magnitude smaller than those involving a spin-allowed process. Moreover, the action of the solvent as a third body appears to play a fundamental role in prompting relatively smooth rates.     

What limits the evolutionary emergence of pathogens?

The ability of a pathogen to cause an epidemic when introduced in a new host population often relies on its ability to adapt to this new environment. Here, we give a brief overview of recent theoretical and empirical studies of such evolutionary emergence of pathogens. We discuss the effects of several ecological and genetic factors that may affect the likelihood of emergence: migration, life history of the infectious agent, host heterogeneity, and the rate and effects of mutations. We contrast different modelling approaches and indicate how details in the way we model each step of a life cycle can have important consequences on the predicted probability of evolutionary emergence. These different theoretical perspectives yield important insights into optimal surveillance and intervention strategies, which should aim for a reduction in the emergence (and re-emergence) of infectious diseases.     

Why on earth?: Evaluating hypotheses about the physiological functions of human geophagy

Geophagy has been hypothesized to be an adaptive behavior, either as a means to allay nutrient deficiency or to protect against ingested pathogens and toxins. Others have proposed that geophagy is non-adaptive, occurring either to allay hunger or as an epiphenomenon of nutrient deficiencies. This paper evaluates these hypotheses using 482 published cultural-level accounts of human geophagy and 330 accounts of geophagy among 297 species of mammals, birds, and reptiles. Information was extracted from reports of human geophagy to permit statistical analysis; reports of non-human geophagy were tabulated. Human geophagy did not parallel changes in nutrient requirements, occurred most frequently among children and pregnant women and in tropical areas (where pathogen densities are highest), and was associated with ingestion of toxic substances and gastrointestinal distress. Earth ingested by humans was craved and carefully selected and prepared; it had high clay content, but few bioavailable mineral nutrients. In primates, geophagy was associated with both protection from toxins and obtaining nutrients, whereas in other vertebrates it was associated mainly with obtaining nutrients. Our results indicate that human geophagy is best explained as providing protection from dietary chemicals, parasites, and pathogens, whereas animal geophagy may involve both micronutrient acquisition and protection.     

Anti-A and anti-B haemagglutinin levels in intravenous immunoglobulins: Are they on the rise? A comparison of four different analysis methods and six products

Recent reports of severe haemolytic reactions upon high dose treatment with new generation intravenous immunoglobulins (IVIGs) prompted us to examine the anti-A and anti-B haemagglutinin content of these therapeutics. We compared four different test methods, namely the indirect and direct haemagglutination test as described in the European Pharmacopoiea (Ph. Eur.) and two commercial gelcard systems with the aim to define the most reliable method for a large-scale comparison of different IVIG products. Absolute titres varied when the same samples were analyzed by the four methods, while the relative ranking of six different IVIG preparations representing different manufacturing classes was identical. New generation IVIGs showed 1–2 titre steps higher anti-A titres than the older products. Haemagglutinin titres of all 48 IVIG batches analyzed were within the current Ph. Eur. specification of ≤1:64 when tested by the official pharmacopoeial method. Based on efficiency, reliability and lower costs, the direct gelcard method could be a valid alternative to the official Ph. Eur. method to serve as a limit test. However, due to the highest intermediate precision, the official Ph. Eur. method seems to be most suitable to compare haemagglutinin titres of different IVIG products.     

Where does fission yeast sit on the tree of life?

The budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe are as different from each other as either is from animals: their ancestors separated about 420 to 330 million years ago. Now that S. pombe is poised to join the post-genome era, its evolutionary position should become much clearer.     

Are comparisons of species distribution models biased? Are they biologically meaningful?

A major problem in ecology is to understand how environmental requirements change over space and time. To this end, numerous authors have attempted to use comparisons of species’ distributions as a surrogate for comparisons of environmental requirements. Unfortunately, it is currently unclear when comparisons of species’ distributions produce reliable inferences about changes in environmental requirements. To address this problem, I develop an analytic model that identifies the conditions under which a comparison of species’ distribution models can serve as surrogate for a comparison of environmental requirements. This work demonstrates that 1) comparisons of species’ distributions typically produce biased comparisons of environmental requirements, 2) assuming distribution models are fit appropriately, it is possible to compare environmental requirements of distinct taxa, 3) there are multiple biologically relevant questions we can address using comparisons of distribution models, with each question corresponding to a distinct measure of the difference between distribution models. By developing an analytic model for comparisons of species’ distributions this work helps to clarify and remedy poorly understood sources of error associated with existing methods.     

Are the Effects of Response Inhibition on Gambling Long-Lasting?

A recent study has shown that short-term training in response inhibition can make people more cautious for up to two hours when making decisions. However, the longevity of such training effects is unclear. In this study we tested whether training in the stop-signal paradigm reduces risky gambling when the training and gambling task are separated by 24 hours. Two independent experiments revealed that the aftereffects of stop-signal training are negligible after 24 hours. This was supported by Bayes factors that provided strong support for the null hypothesis. These findings indicate the need to better optimise the parameters of inhibition training to achieve clinical efficacy, potentially by strengthening automatic associations between specific stimuli and stopping.