Interpreting digit ratio (2D:4D)–behavior correlations: 2D:4D sex difference,stability, and behavioral correlates and their replicability in young children

The popularity of using the ratio of the second to the fourth digit (2D:4D) to study influences of early androgen exposure on human behavior relies, in part, on a report that the ratio is sex-dimorphic and stable from age 2 years (Manning etal., 1998). However, subsequent research has rarely replicated this finding. Moreover, although 2D:4D has been correlated with many behaviors, these correlations are often inconsistent. Young children's 2D:4D–behavior correlations may be more consistent than those of older individuals, because young children have experienced fewer postnatal influences. To evaluate the usefulness of 2D:4D as a biomarker of prenatal androgen exposure in studies of 2D:4D–behavior correlations, we assessed its sex difference, temporal stability, and behavioral correlates over a 6- to 8-month period in 126, 2- to 3-year-old children, providing a rare same-sample replicability test. We found a moderate sex difference on both hands and high temporal stability. However, between-sex overlap and within-sex variability were also large. Only 3 of 24 correlations with sex-typed behaviors—scores on the Preschool Activities Inventory (PSAI), preference for a boy-typical toy, preference for a girl-typical toy, were significant and in the predicted direction, all of which involved the PSAI, partially confirming findings from another study. Correlation coefficients were larger for behaviors that showed larger sex differences. But, as in older samples, the overall pattern showed inconsistency across time, sex, and hand. Therefore, although sex-dimorphic and stable, 2D:4D–behavior correlations are no more consistent for young children than for older samples. Theoretical and methodological implications are discussed.     

Serum elastase 1 and immunoreactive trypsin in chronic pancreatic disease: is there any relationship with trypsin inhibitors?

In order to investigate modifications of serum levels of elastase 1, immunoreactive trypsin, alpha 1-antitrypsin and alpha 2-macroglobulin in chronic pancreatic disease, and to speculate on the possible relationships among these parameters, the enzymes and inhibitors were assayed in the sera of 33 control subjects, 34 pancreatic cancer, 28 chronic pancreatitis and 36 extra-pancreatic diseases. An increase of elastase 1, alpha 1-antitrypsin and alpha 2-macroglobulin was detected in pancreatic cancer, chronic pancreatitis and extra-pancreatic diseases; no changes were found for serum immunoreactive trypsin. Multiple regression analyses showed that only 7% of elastase 1 was explained by inhibitors with alpha 1-antitrypsin playing a major role. Inhibitors did not influence immunoreactive trypsin. Our data indicate that the variations of the serum levels of proteases and antiproteases in chronic pancreatic disease are probably independent of each other.     

High sulfhydryl content in turtle erythrocytes: is there a relation with resistance to hypoxia?

Glutathione concentration in the erythrocytes of the fresh-water turtle Phrynops hilarii, as determined by the enzymic recycling method is 1.9 +/- 0.2 mM. The erythrocyte non-protein -SH, NPSH, content, as determined by the 5,5' dithiobis(2-nitrobenzoic acid), DTNB, reducing capacity is 4.6 +/- 0.8 mM. The total DTNB reducing capacity in the erythrocytes, including hemoglobin, is 26 +/- 5 mM. Incubation with oxidized glutathione, greatly increases the electrophoretic mobility of both hemoglobin components present in the erythrocytes of Phrynops hilarii, indicating the formation of mixed disulphides with glutathione. The high --SH content in the erythrocytes of P. hilarii might be part of a redox buffering principally an antioxidant mechanism involved in resistance to hypoxia, possibly along the hypoxic period as well as during reperfusion with oxygen.     

General practice consultations: is there any point in being positive?

A group of 200 patients who presented in general practice with symptoms but no abnormal physical signs and in whom no definite diagnosis was made were randomly selected for one of four consultations: a consultation conducted in a "positive manner," with and without treatment, and a consultation conducted in a "non-positive manner," called a negative consultation, with and without treatment. Two weeks after consultation there was a significant difference in patient satisfaction between the positive and negative groups but not between the treated and untreated groups. Similarly, 64% of those receiving a positive consultation got better, compared with 39% of those who received a negative consultation (p = 0.001) and 53% of those treated got better compared with 50% of those not treated (p = 0.5).     

HLA-DR4 and career prospects in rheumatology: is there a link?

OBJECTIVE--To determine whether HLA type is associated with career progress in rheumatology. DESIGN--Comparison of HLA type after HLA analysis of samples of venous blood. SETTING--Department of Rheumatology Research, University of Birmingham. SUBJECTS--All (37) staff in the department. RESULTS--All the senior academics and most staff with a PhD expressed HLA-DR4. The prevalence of expression in each of these groups was significantly greater than that found in the controls. None of the junior doctors or secretaries expressed DR4. CONCLUSION--The junior doctors in the department have poor career prospects as HLA-DR4 seems to be associated with academic achievement.     

Estimating sex ratio biases in X-linked disorders: is there an excess of males in families with X-linked ichthyosis?

We derive the conditional probabilities for estimating the sex ratio in families ascertained through affected males for the study of X-linked recessive diseases. These conditional probabilities correct for the fact that the probability that a family will be ascertained increases with the number of males in the family. Data from four published studies for X-linked ichthyosis vulgaris are analyzed, three having an excess of males and one having a highly statistically significant excess of males. It is not known if this difference in the two samples represents a biological difference between the two populations or an unrecognized ascertainment bias.     

How many genes are there in plants (… and why are they there)?

Annotation of the first few complete plant genomes has revealed that plants have many genes. For Arabidopsis, over 26,500 gene loci have been predicted, whereas for rice, the number adds up to 41,000. Recent analysis of the poplar genome suggests more than 45,000 genes, and partial sequence data from Medicago and Lotus also suggest that these plants contain more than 40,000 genes. Nevertheless, estimations suggest that ancestral angiosperms had no more than 12,000-14,000 genes. One explanation for the large increase in gene number during angiosperm evolution is gene duplication. It has been shown previously that the retention of duplicates following small- and large-scale duplication events in plants is substantial. Taking into account the function of genes that have been duplicated, we are now beginning to understand why many plant genes might have been retained, and how their retention might be linked to the typical lifestyle of plants.     

Understanding height-structured competition in forests: is there an R* for light?

Tree species differ from one another in, and display trade-offs among, a wide range of attributes, including canopy and understorey growth and mortality rates, fecundity, height and crown allometry, and crown transmissivity. But how does this variation affect the outcome of interspecific competition and hence community structure? We derive criteria for the outcome of competition among tree species competing for light, given their allometric and life-history parameters. These criteria are defined in terms of a new simple whole life-cycle measure of performance, which provides a simple way to organize and understand the many ways in which species differ. The general case, in which all parameters can differ between species, can produce coexistence, founder control or competitive exclusion: thus, competition for light need not be hierarchical as implied by R^* theory. The special case in which species differ only in crown transmissivity produces neutral dynamics. The special case in which species differ in all parameters except crown transmissivity gives hierarchical competition, where the equivalent of R^* is Zˆ*, the height at which trees enter the canopy in an equilibrium monoculture.     

Were there any "misassignments" among iron-sulfur clusters N4, N5 and N6b in NADH-quinone oxidoreductase (complex I)?

NADH-quinone oxidoreductase (complex I) in bovine heart mitochondria has a molecular weight of approximately 1 million Da composed of 45 distinct subunits. It is the largest energy transducing complex so far known. Bacterial complex I is simpler and smaller, but the essential redox components and the basic mechanisms of electron and proton translocation are the same. Over the past three decades, Ohnishi et al. have pursued extensive EPR studies near liquid helium temperatures and characterized most of the iron-sulfur clusters in complex I. Recently, Yakovlev et al. [G. Yakovlev, T. Reda, J. Hirst, Reevaluating the relationship between EPR spectra and enzyme structure for the iron-sulfur clusters in NADH:quinone oxidoreductase, Proc. Natl. Acad. Sci. U. S. A. 104 (2007) 12720-12725] challenged Ohnishi's group by claiming that there were EPR "misassignments" among clusters N4, N5 and N6b (in order to prevent confusion, we used current consensus nomenclature, as the nickname). They claimed that we misassigned EPR signals arising from cluster N5 to cluster N4, and signals from cluster N6b to cluster N4. They also proposed that cluster N5 has (4Cys)-ligands. Based on the accumulated historical data and recent results of our site-specific mutagenesis experiments, we confirmed that cluster N5 has (1His+3Cys)-ligands as we had predicted. We revealed that E. coli cluster N5 signals could be clearly detected at the sample temperature around 3 K with microwave power higher than 5 mW. Thus Hirst's group could not detect N5 signals under any of their EPR conditions, reported in their PNAS paper. It seems that they misassigned the signals from cluster N4 to N5. As to the claim of "misassignment" between clusters N4 and N6b, that was not a possibility because our mutagenesis systems did not contain cluster N6b. Therefore, we believe that we have not made any "misassignment" in our work.     

Dietary habits and plasma fatty acids levels in a population of Italian children: is there any relationship?

The relationships between dietary habits and the blood fatty acid (FA) profile have been poorly explored, particularly in children. Aim of the present investigation was to look at the associations between dietary habits and the plasma pattern of FA in a school-age population. In 105 healthy 8-years old children, the nutritional habits have been evaluated by means of a Food Frequency Questionnaire and a 24-h recall. FA analyses (expressed as FA%) were performed by means of capillary gas chromatography. Statistics: non-parametric tests. The children with high pasta and low red meat consumption (n = 9), compared to those with either medium or low pasta and either high or medium red meat consumption (n = 96), showed lower levels of total saturated (29% vs. 35%, P = 0.001) and higher levels of total monounsaturated (30% vs. 24%, P = 0.04) FA in plasma. They also showed lower levels of LDL cholesterol (90 vs. 109 mg/dl, P = 0.08) and fasting insulin (4.0 vs. 6.3 microU/ml, P = 0.04) in blood. A high consumption of pasta coupled with a low intake of red meat may be marker of a food behaviour and/or lifestyle associated with a more favourable pattern of circulating FA and hematochemical metabolic markers.     

Is there any correlation between binding and functional effects at the translocator protein (TSPO) (18 kDa)?

The translocator protein (TSPO) is a potential drug target for the treatment of CNS diseases, with TSPO ligands being able to modulate steroidogenesis, apoptosis, and cell proliferation. While there exist multiple TSPO binding sites, the nature of these sites--either overlapping or allosterically linked--remains largely uncharacterized. Furthermore, while evidence suggests that microglial activation and polymerization result in changes to TSPO binding sites, these changes are poorly understood. While current pharmacophoric models can be used to synthesize TSPO ligands with high affinity and selectivity, these models are unable to predict ligands with desirable functional effects. Better characterization of TSPO binding sites in health and disease may provide insight into particular sites which mediate promising therapeutic profiles, thus refining the TSPO pharmacophore.     

Trophic structure of a neotropical frugivore community: is there competition between birds and bats?

Summary Dietary overlap and competition between frugivorous birds and bats in the Neotropics have been presumed to be low, but comparative data have been lacking. We determined the diets of volant frugivores in an early successional patch of Costa Rican wet forest over a one month period. Ordination of the diet matrix by Reciprocal Averaging revealed that birds and bats tend to feed on different sets of fruits and that diets differed more among bat species than among bird species. However, there was overlap between Scarlet-rumped Tanagers and three Carollia bat species on fruits of several Piper species which comprised most of the diet of these bats. Day/night exclosure experiments on P. friedrichsthalli treetlets provided evidence that birds deplete the amount of ripe fruit available to bats. These results indicate that distantly related taxa may overlap in diet and compete for fruit, despite the apparent adaptation of animal-dispersed plant species for dispersal by particular animal taxa.     

Were there any “misassignments” among iron–sulfur clusters N4, N5 and N6b in NADH-quinone oxidoreductase (complex I)?

NADH-quinone oxidoreductase (complex I) in bovine heart mitochondria has a molecular weight of approximately 1 million Da composed of 45 distinct subunits. It is the largest energy transducing complex so far known. Bacterial complex I is simpler and smaller, but the essential redox components and the basic mechanisms of electron and proton translocation are the same. Over the past three decades, Ohnishi et al. have pursued extensive EPR studies near liquid helium temperatures and characterized most of the iron–sulfur clusters in complex I. Recently, Yakovlev et al. [G. Yakovlev, T. Reda, J. Hirst, Reevaluating the relationship between EPR spectra and enzyme structure for the iron-sulfur clusters in NADH:quinone oxidoreductase, Proc. Natl. Acad. Sci. U. S. A. 104 (2007) 12720–12725] challenged Ohnishi's group by claiming that there were EPR “misassignments” among clusters N4, N5 and N6b (in order to prevent confusion, we used current consensus nomenclature, as the nickname). They claimed that we misassigned EPR signals arising from cluster N5 to cluster N4, and signals from cluster N6b to cluster N4. They also proposed that cluster N5 has (4Cys)-ligands. Based on the accumulated historical data and recent results of our site-specific mutagenesis experiments, we confirmed that cluster N5 has (1His + 3Cys)-ligands as we had predicted. We revealed that E. coli cluster N5 signals could be clearly detected at the sample temperature around 3 K with microwave power higher than 5 mW. Thus Hirst's group could not detect N5 signals under any of their EPR conditions, reported in their PNAS paper. It seems that they misassigned the signals from cluster N4 to N5. As to the claim of “misassignment” between clusters N4 and N6b, that was not a possibility because our mutagenesis systems did not contain cluster N6b. Therefore, we believe that we have not made any “misassignment” in our work.