Is non‐loglinear allometry a statistical artifact?

The allometric equation, y = ax^b, is commonly fitted to data indirectly by transforming predictor (x) and response (y) variables to logarithms, fitting a straight line to the transformations, and then back‐transforming (exponentiating) the resulting equation to the original arithmetic scale. Sometimes, however, transformation fails to linearize the observations, thereby giving rise to what has come to be known as non‐loglinear allometry. A smooth curve for observations displayed on a log–log plot is usually interpreted to mean that the scaling exponent in the allometric equation is a continuously changing function of body size, whereas a breakpoint between two (or more) linear segments on a log–log plot is typically taken to mean that the exponent changes abruptly, coincident with some important milestone in development. I applied simple graphical and statistical procedures in re‐analyses of three well‐known examples of non‐loglinear allometry, and showed in every instance that the relationship between predictor and response can be described in the original scale by simple functions with constant values for the exponent b. In no instance does the allometric exponent change during the course of development. Transformation of data to logarithms created new distributions that actually obscured the relationships between predictor and response variables in these investigations, and led to erroneous perceptions of growth. Such confounding effects of transformation are not limited to non‐loglinear allometry but are common to all applications of the allometric method. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Erectile dysfunction after myocardial infarction--myth or a real problem?

Erectile dysfunction is a common problem whose relation to cardiovascular diseases has scientifically been proved, but it has not been studied sufficiently in patients recovering from myocardial infarction. The objective of this study was to establish the frequency of erectile dysfunction in patients recovering from myocardial infarction. We examined 89 patients (aged 30 to 75 years) included in the program of cardiac rehabilitation after myocardial infarction. The results were compared with 91 healthy examinees of the same age. Even 82% of the patients who recovered from myocardial infarction have problems with erectile dysfunction, compared to 42.9% of healthy examinees. The prevalence of erectile dysfunction increases with the age in both groups. In the group of patients recovering from myocardial infarction aged 30 do 39 years, the erectile dysfunction decreased after 6 months, while in other age subgroups and between controls, there were no significant changes in erectile dysfunction prevalence during the analysed time period. We concluded that erectile dysfunction is a significant problem in patients recovering from myocardial infarction. It should be recognized on time in order to provide a better life quality for the patient with a multidisciplinary approach.     

Trimodality treatment in malignant pleural mesothelioma – Ordeal or real deal?

BackgroundManagement of MPM is complex and controversial as there is a paucity of good quality evidence. We report the toxicity and outcomes in patients who received trimodality treatment for non-metastatic MPM at our institution.Methods & materialsWe reviewed the electronic medical records of surgically managed MPM patients at our institution in the last decade. Dosimetric parameters of target volume and organs at risk were documented by the treatment planning workstation. SPSS was used for statistical analysis.ResultsBetween January 2008 and October 2018, 21 patients underwent surgery for MPM – all but 2 patients underwent extra-pleural pneumonectomy (EPP); epithelioid MPM was the most common histology. All patients, except 2, received neoadjuvant Pemetrexed/platinum doublet chemotherapy. Fourteen patients received adjuvant hemithoracic RT; ten patients were treated with a conformal technique at our institute and dosimetric data was available for analysis. Average time to start RT after surgery was 51 days (range 32–82 days). All patients were treated with a conformal technique using IMRT/VMAT to a dose of 45Gy in 25 fractions. Mean overall RT duration was 35 days (range 30–42 days). Grade I/II Pneumonitis was seen in 4 patients. One patient developed grade III acute lung toxicity unrelated to RT. At a median follow up of 25 months, 8 patients had died, of whom six died due to the disease and two died in the immediate post op period. Two-year DFS and OS were 58% and 73%, respectively.ConclusionIn spite of the extensive surgery and complex hemithoracic RT, we demonstrated excellent dosimetry, toxicity profile and favorable outcomes in non-metastatic MPM.     

Aurora kinases, aneuploidy and cancer, a coincidence or a real link?

As Aurora kinases are overexpressed in a large number of cancers, and ectopic expression of Aurora generates polyploid cells containing multiple centrosomes, it has been tempting to suggest that Aurora overexpression provokes genetic instability underlying the tumorigenesis. However, examination of the evidence suggests a more complex relationship. Overexpression of Aurora-A readily transforms rat-1 and NIH3T3 cells, but not primary cells, whereas overexpression of Aurora-B induces metastasis after implantation of tumors in nude mice. Why do polyploid cells containing abnormal centrosome numbers induced by Aurora not get eliminated at cell-cycle checkpoints? Does this phenotype determine the origin of cancer or does it only promote tumor progression? Would drugs against Aurora family members be of any help for cancer treatment? These and related questions are addressed in this review (which is part of the Chromosome Segregation and Aneuploidy series).     

HTLV-1: A real pathogen or a runaway guest of a diseased cell?

The human T-cell lymphotropic virus type 1 (HTLV-1) is a deltaretrovirus claimed to be aetiologically linked to the adult T-cell leukaemia/lymphoma (ATLL) and associated myelopathy/tropical spastic paraparesis (HAM/TSP) besides other minor pathologies. HTLV-1 infection is worldwide distributed, despite its heterogeneous prevalence. Environmental factors and host-genetic background are very likely to determine the epidemiological profile of HTLV-1 prevalence and related disease confinement in distinct human ethnic populations and geographical coordinates, which raises the question if the virus is a real pathogen or a runaway well-organized packed genome of a burden host cell near death process. New methodological approaches need to be proposed and applied in order to prove or discard the hypotheses emerged in the present review.     

Under-labourer or ϋber-labourer – a zero sum game?

Banton and Rex's differences in their analysis of race and ethnic relations rest not so much on the contrast between ‘prophet’ and ‘scientist’, but rather on two quite different perspectives on the nature of sociology itself. Each in their own way has much to offer the field, which explains their continuing relevance to this area of study.     

Genomics and post-genomics in parasitology: genome babble or a real opportunity?

The genome projects represent one of the most important developments in our knowledge of parasites. However, translation of this knowledge into an understanding of parasite biology and then on to drugs, vaccines and other healthcare developments for the diseases will need some élan and clarity of thought by scientists and funding organizations. Only then will the activity associated with post-genomics be turned from what I have termed 'genome babble' to real opportunities in understanding these parasites.     

Are white-rot fungi a real biotechnological option for the improvement of environmental health?

The use of white-rot fungi as a biotechnological tool for cleaning the environment of recalcitrant pollutants has been under evaluation for several years. However, it is still not possible to find sufficiently detailed investigations of this subject to conclude that these fungi can decontaminate the environment. In the present review, we have summarized and discussed evidence about the potential of white-rot fungi to degrade such pollutants as polycyclic aromatic hydrocarbons, dyes or antibiotics as an example of the complex structures that these microorganisms can attack. This review also discusses field experiment results and limitations of white-rot fungi trials from contaminated sites. Moreover, the use of catabolic potential of white-rot fungi in biopurification systems (biobeds) is also discussed. The current status and future perspectives of white-rot fungi, as a viable biotechnological alternative for improvement of environmental health are noted.     

The association of glycosomal enzymes and microtubules: a physiological phenomenon or an experimental artifact?

Subpellicular microtubules isolated from Trypanosoma brucei parasites were fractionated on a phosphocellulose column, and the trypanosomal p52 microtubule-associated protein was eluted along with two other proteins of 41 and 36 kDa. These proteins were found to be the glycosomal enzymes aldolase (41 kDa) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH, 36 kDa) by enzyme activity, antibody cross-reaction, and N-terminal sequencing. These enzymes were coprecipitated with tubulin in the presence of taxol, and aldolase had the capacity to polymerize tubulin and crosslink microtubules. Immunolocalization of anti-aldolase and anti-GAPDH antibodies did not show an interaction between these enzymes and the subpellicular microtubules. The question whether the copurification of aldolase and the subpellicular microtubules could reflect a physiological phenomenon or may be an experimental artifact is discussed.     

Glucose-induced buffering of cytoplasmic Ca2+ in the pancreatic beta-cell--an artifact or a physiological phenomenon?

The effects of stimulated metabolism on the cytoplasmic Ca2+ concentration (Ca2+i) of insulin-releasing pancreatic beta-cells were studied. When the glucose concentration was increased from 5 to 20 mM, some cell preparations responded with initial lowering of Ca2+i followed by a rise, whereas Ca2+i only increased in others. After prolonged exposure to 5 or 10 mM of the sugar, depolarization with high concentrations of sulfonylurea or K+ caused rapid increases of Ca2+i. However, when subsequently raising glucose to 20 mM there were pronounced temporary decreases of Ca2+i. Marked Ca2+i reducing effects were also obtained after prolonged exposure to 20 mM glucose, when metabolism was augmented further by exposure to leucine or beta-2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid. The results indicate that buffering of Ca2+i is not an artifact but may have physiological significance.