Further development of forensic eye color predictive tests

In forensic analysis predictive tests for external visible characteristics (or EVCs), including inference of iris color, represent a potentially useful tool to guide criminal investigations. Two recent studies, both focused on forensic testing, have analyzed single nucleotide polymorphism (SNP) genotypes underlying common eye color variation (Mengel-From et al., Forensic Sci. Int. Genet. 4:323 and Walsh et al., Forensic Sci. Int. Genet. 5:170). Each study arrived at different recommendations for eye color predictive tests aiming to type the most closely associated SNPs, although both confirmed rs12913832 in HERC2 as the key predictor, widely recognized as the most strongly associated marker with blue and brown iris colors. Differences between these two studies in identification of other eye color predictors may partly arise from varying approaches to assigning phenotypes, notably those not unequivocally blue or dark brown and therefore occupying an intermediate iris color continuum. We have developed two single base extension assays typing 37 SNPs in pigmentation-associated genes to study SNP-genotype based prediction of eye, skin, and hair color variation. These assays were used to test the performance of different sets of eye color predictors in 416 subjects from six populations of north and south Europe. The presence of a complex and continuous range of intermediate phenotypes distinct from blue and brown eye colors was confirmed by establishing eye color populations compared to genetic clusters defined using Structure software. Our study explored the effect of an expanded SNP combination beyond six markers has on the ability to predict eye color in a forensic test without extending the SNP assay excessively - thus maintaining a balance between the test's predictive value and an ability to reliably type challenging DNA with a multiplex of manageable size. Our evaluation used AUC analysis (area under the receiver operating characteristic curves) and naïve Bayesian likelihood-based classification approaches. To provide flexibility in SNP-based eye color predictive tests in forensic applications we modified an online Bayesian classifier, originally developed for genetic ancestry analysis, to provide a straightforward system to assign eye color likelihoods from a SNP profile combining additional informative markers from the predictors analyzed by our study plus those of Walsh and Mengel-From. Two advantages of the online classifier is the ability to submit incomplete SNP profiles, a common occurrence when typing challenging DNA, and the ability to handle physically linked SNPs showing independent effect, by allowing the user to input frequencies from SNP pairs or larger combinations. This system was used to include the submission of frequency data for the SNP pair rs12913832 and rs1129038: indicated by our study to be the two SNPs most closely associated to eye color.

Severe diaphragmatic hernia treated by fetal endoscopic tracheal occlusion

OBJECTIVES

To examine operative and perinatal aspects of fetal endoscopic tracheal occlusion (FETO) in congenital diaphragmatic hernia (CDH).

METHODS

This was a multicenter study of singleton pregnancies with CDH treated by FETO. The entry criteria for FETO were severe CDH on the basis of sonographic evidence of intrathoracic herniation of the liver and low lung area to head circumference ratio (LHR) defined as the observed to the expected normal mean for gestation (o/e LHR) equivalent to an LHR of 1 or less.

RESULTS

FETO was carried out in 210 cases, including 175 cases with left-sided, 34 right-sided and one with bilateral CDH. In 188 cases the CDH was isolated and in 22 there was an associated defect. FETO was performed at a median gestational age of 27.1 (range, 23.0-33.3) weeks. The first eight cases were done under general anesthesia, but subsequently either regional or local anesthesia was used. The median duration of FETO was 10 (range, 3-93) min. Successful placement of the balloon at the first procedure was achieved in 203 (96.7%) cases. Spontaneous preterm prelabor rupture of membranes (PPROM) occurred in 99 (47.1%) cases at 3-83 (median, 30) days after FETO and within 3 weeks of the procedure in 35 (16.7%) cases. Removal of the balloon was prenatal either by fetoscopy or ultrasound-guided puncture, intrapartum by ex-utero intrapartum treatment, or postnatal either by tracheoscopy or percutaneous puncture. Delivery was at 25.7-41.0 (median, 35.3) weeks and before 34 weeks in 65 (30.9%) cases. In 204 (97.1%) cases the babies were live born and 98 (48.0%) were discharged from the hospital alive. There were 10 deaths directly related to difficulties with removal of the balloon. Significant prediction of survival was provided by the o/e LHR and gestational age at delivery. On the basis of the relationship between survival and o/e LHR in expectantly managed fetuses with CDH, as reported in the antenatal CDH registry, we estimated that in fetuses with left CDH treated with FETO the survival rate increased from 24.1% to 49.1%, and in right CDH survival increased from 0% to 35.3% (P < 0.001).

CONCLUSIONS

FETO in severe CDH is associated with a high incidence of PPROM and preterm delivery but a substantial improvement in survival.

The close relationship between estimated divergent selection and observed differentiation supports the selective origin of a marine snail hybrid zone

To study the role of divergent selection in the differentiation of the two morphs in a hybrid zone of the intertidal snail Littorina saxatilis, we compared the strength of the divergent selection acting on a series of shell characters (as estimated by the viability of snails in a reciprocal transplant experiment) with the contribution of these characters to the phenotypic differences between the morphs. We found a close correlation between selection and differentiation, which suggests a cause-effect relationship, i.e. that all present differentiation is the result of past divergent selection. In addition, divergent selection was a very important component of the total natural selection acting on shell measures. These novel results support previous evidence, based on allozyme analysis, of a parapatric origin for this hybrid zone. We discuss possible limitations of this interpretation and the circumstances under which allopatric differentiation would produce the same results. Phenotypic analysis of divergent selection may be a useful method of investigating the evolutionary mechanisms involved in differentiation processes.

Testing alternative models for sexual isolation in natural populations of Littorina saxatilis: indirect support for by-product ecological speciation?

Two ecotypes of the rough periwinkle Littorina saxatilis occur at different shore levels, showing assortative mating for size and partial reproductive isolation when they meet at the mid-shore. This system represents a putative case of incomplete speciation in sympatry. Two processes contribute to the assortative mating: morph-specific microhabitat aggregation and mate choice. The estimation of mate choice coefficients in nature and a simulation of the aggregation effects on sexual isolation were used to disentangle these processes as well as to test alternative mechanisms of mate choice. Mate choice significantly increased the frequency of within-morph pairs and significantly decreased the frequency of between-morph pairs, whereas those pairs including at least one hybrid morph mated randomly. These results allow us to reject a discriminant mate choice and support a model of evolution of sexual isolation as a side-effect of size-assortative mating in a context of divergent natural selection for size in the population. This mechanism is more compatible with a model of incomplete by-product ecological speciation, as suggested by previous evidence.

[Glutathione in cognitive function and neurodegeneration]

OBJECTIVE

To review the main findings on the glutathione role in cognitive function and synaptic plasticity processes, as well as, its involvement in neurotrophic and neurodegenerative events in rodents.

DEVELOPMENT

The tripeptide glutathione and its related enzymes participate in the maintenance of oxidant homeostasis in aerobic cells. Oxidative damage to neuronal components underlies the molecular basis of neurodegeneration and brain aging. Several biomolecules with redox dependent activity are involved in the neuronal plasticity events that have a role in learning and memory functions. The maintenance of normal glutathione level is important for acquisition, but not consolidation, of spatial memory. Glutathione unavailability induces failures in hippocampal synaptic plasticity mechanisms, which are possibly related to a spatial memory deficit. On the other hand, several studies have suggested that the beneficial effects of neurotrophic treatments are mediated by the modulation of antioxidant defense mechanisms. In fact, nerve growth factor treatment to cognitively impaired rats stimulates glutathione reductase and can prevent the increases in glutathione peroxidase activity, pointing these enzymes as possible intracellular targets of neurotrophin actions on oxidant homeostasis.

CONCLUSION

There is a closed link between glutathione metabolism and oxidant homeostasis, which is expressed in learning and synaptic plasticity deficits in conditions of low glutathione content, as well as, in neurodegeneration induced glutathione metabolism changes that can be prevented by neurotrophic treatment

Kin discrimination within honey bee (Apis mellifera) colonies: An analysis of the evidence

Compelling evolutionary arguments lead to the prediction that honey bee workers should discriminate between supersisters and half-sisters within colonies. We review the theoretical support for discrimination during swarming, queen rearing, feeding, and grooming. A survey of the data that tests whether such discrimination takes place shows that, despite substantial effort in a number of laboratories, there is no conclusive evidence for intracolony discrimination in any of the postulated contexts. The strongest suggestive data is in the critical context of queen rearing, but flaws in experimental design or analysis make the best available tests inconclusive. We present new data that shows that cues exist on which discriminations can be made among adult workers in nestmate recognition interactions and in feeding interactions, but our data does not differentiate between subfamily recognition and recognition associated with color phenotypes. We conclude that while selection may favor discrimination between supersisters and half-sisters, as a practical matter such discriminations play no role, or only a minor role, in the biology of the honey bee.

Immunohistochemical localization and electrophysiological action of nociceptin/orphanin-FQ in the snail (Helix aspersa) neurons

We report the existence and anatomical distribution to nociceptin/orphanin-FQ (N/O FQ)-like immunoreactivity in neurons and fibers in the perioesophageal ganglia of the snail (Helix aspersa). Intracellular recordings from perioesophageal ganglion neurons showed that the application of 10 microM N/O FQ produced an excitatory action in 22% of the neurons studied and an inhibitory action in 33% of the neurons regardless of their origin (cerebral or parietal ganglion). Our result provides evidence that N/O FQ-like peptide is located in whole perioesophageal ganglia (mainly in the cerebral one), and that it may serve as a neuromodulator of the neuronal spike discharge. These data support the idea that the N/O FQ opioid system has an early phylogenetic origin and a functional continuity during the course of evolution.

Increases in fines and driver licence withdrawal have effectively reduced immediate deaths from trauma on Brazilian roads: first-year report on the new traffic code

Road accidents are a major cause of death in Brazil, with rates increasing steadily for years. Our objective here is to report the impact of the new Brazilian Traffic Code, introduced in 1998. Its main new features include a large increase in fines and a rigid penalty scoring system that leads to driver license withdrawal. Speed limits have actually been raised on many roads, but adherence to the rules has been monitored more closely. We compare the incidence of injured patients and immediate deaths in road accidents and emergency room admissions to a level I trauma centre in downtown São Paulo between January and December 1998 with corresponding data from between January and December 1997. There was an overall 21.3% reduction in the number of accidents and a 24.7% reduction in immediate deaths, saving 5962 lives on Brazilian highways. Tickets issued fell by 49.5% (601977 during 1997 to 304785 during 1998). Motor vehicle accident-related emergency room admissions decreased by 33.2%. We conclude that very costly tickets and threatened driver licences have proved very effective in decreasing immediate deaths from trauma. Further advances in educational programmes associated with road and vehicle safety measures are likely to provide the much needed further reduction in the still high trauma mortality on Brazilian roads and streets.

[Dural fistulas of the anterior cranial fossa]

Dural arterio-venous shunts (DAVS) of the anterior cranial fossa are quite rare. There are only a few cases reported in the literature. The authors present 5 cases of dural arterio-venous shunts (DAVS) of the anterior cranial fossa, allowing more data for later reviews of this rare and aggressive localisation of DAVS. The clinical set, imaging findings (with emphasis in diagnostic angiography), treatment and outcome in these 5 patients are described. Haemorrhage was the presenting form in 4 patients; the other case presented was investigated for headache. There were bilateral symmetric feeders in two patients, unilateral feeders in another two and unilateral predominant feeders in one; contribution of the external carotid artery, when present, was always minimal. Venous drainage included one or combinations of these: superior sagittal sinus, sylvian veins and cavernous sinus. Three patients had venous aneurysms in anterior cranial fossa; of these, two presented with haemorrhage, but the third one of them has been asymptomatic for 7 years. Three patients were treated by surgical exclusion of the shunt and became clinical and angiographicaly normal. According to the literature, our cases confirm the highly aggressive behaviour of these DAVS. Surgical treatment is an efficacious method of therapy and should be done as soon as possible. Embolization can be attempted but is technically difficult and eventually too expensive.