Selenium does not affect radiosensitivity of breast cancer cell lines.

Supplementation with the antioxidant selenium is frequently performed in breast cancer patients to protect the normal tissue from radiation-induced side effects. However, concerns exist whether selenium also protects tumor cells from radiation-induced cell kill and thereby reduces the efficacy of radiotherapy. In this work, the effect of selenium administration on the radiosensitivity of breast cancer cells was evaluated in vitro. Physiological relevant selenium concentrations (70 and 140 µg/l) did not affect DNA double-strand breaks (γH2AX foci) after 4-Gy X-ray irradiation. Also apoptosis (caspase 3/7) after irradiation with 10 Gy was not influenced by selenium treatment in MDA-MB-231 and MCF7 cells. Most importantly, selenium supplementation did not impair the clonogenic survival of the breast cancer cell lines after irradiation (0, 2, 4, 6, 8 Gy). The data suggest that physiological relevant selenium concentrations administered in combination with radiation therapy do not deteriorate the efficacy of radiotherapy in breast cancer patients. However, randomized clinical trials comparing the effectiveness of radiotherapy and the associated side effects in patients with and without selenium supplementation are recommended.

Language specific prosodic preferences during the first half year of life: evidence from German and French infants.

There is converging evidence that infants are sensitive to prosodic cues from birth onwards and use this kind of information in their earliest steps into the acquisition of words and syntactic regularities of their target language. Regarding word segmentation, it has been found that English-learning infants segment trochaic words by 7.5 months of age, and iambic words only by 10.5 months of age [Jusczyk, P. W., Houston, D. M., & Newsome, M. (1999). The beginnings of word segmentation in English-learning infants. Cognitive Psychology, 39, 159-207]. The question remains how to interpret this finding in relation to results showing that English-learning infants develop a preference for trochaic over iambic words between 6 and 9 months of age [Jusczyk, P. W., Cutler, A., & Redanz, N. (1993). Preference for the predominant stress patterns of English words. Child Development, 64, 675-687]. In the following, we report the results of four experiments using the headturn preference procedure (HPP) to explore the trochaic bias issue in German- and French-learning infants. For German, a trochaic preference was found at 6 but not at 4 months, suggesting an emergence of this preference between both ages (Experiments 1 and 2). For French, 6-month-old infants did not show a preference for either stress pattern (Experiment 3) while they were found to discriminate between the two stress patterns (Experiment 4). Our findings are the first to demonstrate that the trochaic bias is acquired by 6 months of age, is language specific and can be predicted by the rhythmic properties of the language in acquisition. We discuss the implications of this very early acquisition for our understanding of the emergence of segmentation abilities.

Parental bilingualism is associated with slower cognitive development in very low birth weight infants.

BACKGROUND: Speech development is frequently impaired in very low birth weight (VLBW) infants. Few and controversial data have been published on concepts regarding the influence of bilingual education. AIMS: The objectives of the current study were to assess the influence of parental bilingualism on speech development and neurodevelopmental outcome in low risk VLBW infants. STUDY DESIGN: Monocentric prospective controlled cohort study with standardized follow-up. SUBJECTS: We recruited 50 singleton VLBW infants each from monolingual and bilingual families as well as 90 term control infants. The infants were free of disease and congenital malformation. OUTCOME MEASURES: Griffiths scales of infant development at the corrected ages of 6 and 12 months, Bayley Scales of Infant Development II (BSID II) with 22 months. RESULTS: In general, both bilingual and monolingual VLBW infants achieved age-specific milestones at the corrected age of 6, 12 and 22 months. However, bilingual VLBW infants achieved significantly lower scores than their monolingual peers in all cognitive subscales. The influence of maternal education on the neurodevelopmental outcome of the preterm infants was not significant; the subscales' correlation with socioeconomic or biological parameters was poor. However, a clear differentiation between social status and bilingual environment importance for speech development was not possible. CONCLUSIONS: In the setting of the present investigation, parental bilingualism is associated with slower neurodevelopment in VLBW infants during the first 2 years of life.

ERP correlates of processing native and non-native language word stress in infants with different language outcomes.

The early acquisition of native language prosody is assumed to ease infants' language development. In a longitudinal setting we investigated whether the early processing of native and non-native language word stress patterns is associated with children's subsequent language skills. ERP data of 71 four- and five-month-old infants were retrospectively grouped according to children's verbal performance in a language test at 2.5 years. Children who displayed age-adequate expressive language skills later in development showed both an early and a late negative mismatch response (MMR) when processing the native language stress pattern as deviant in a passive oddball design. Children with poor language skills later in development did not show these negativities. Both groups displayed an infant-specific positive MMR to the non-native language deviant. This positivity was enhanced and prolonged in children who showed poor language skills later in development as compared to children who showed normal language skills. The results indicate that variability in expressive language development has precursors in infants' ERP correlates of word stress processing.

Impaired word stress pattern discrimination in very-low-birthweight infants during the first 6 months of life.

Prosodic information, such as word stress and speech rhythm, is important in language acquisition, and sensitivity to stress patterns is present from birth onwards. Exposure to prosodic properties of the native language occurs prenatally. Preterm birth and an associated lack of exposure to prosodic information are suspected to affect language acquisition in preterm infants. Fifty healthy very low birthweight (<1500 g) preterm German infants (24 males, 26 females; mean gestational age [GA] 27.6 wks, range 26.4-29.9) and 103 comparison term infants (48 males, 55 females; mean GA 40 wks, range 39.4-40.8) were recruited. Prosodic discrimination performance was assessed using the head-turn preference paradigm, an objective behavioural psycholinguistic test for measuring orientation time (OT) to auditory stress patterns. Among matched preterm and term infants, preterm infants (n=30) did not differentiate stress patterns at the corrected age of 4 or 6 months. In term infants (n=30), the OT was longer towards the trochaic (stress on first syllable, characteristic for German) than the iambic (second syllable) stress patterns (11.64 vs 9.18s, p<0.001, and 11.02 vs 8.32s, p<0.001, at 4 and 6 mo respectively). Neurodevelopmental scores (Bayley Scales of Infant Development, 2nd edn) were not different from reference values in both groups of infants. Preterm birth and deficient early prosodic information affect prosodic processing during the first half year of life.