Different administration schedules of darbepoetin alfa affect oxidized and reduced glutathione levels to a similar extent in 5/6 nephrectomized rats

Background

The development of erythropoiesis-stimulating agents (ESAs) with extended serum half-lives has allowed marked prolongation of the administration intervals. The level of oxidative stress is increased in chronic kidney disease, and is reportedly decreased after long-term ESA treatment. However, the effect of different dosing regimens of ESAs on oxidative stress has not been elucidated.

Methods

Five-sixths nephrectomized (NX) rats received either 0.4 μg/kg darbepoetin alfa (DA) weekly or 0.8 μg/kg DA fortnightly between weeks 4 and 10. NX animals receiving saline and a sham-operated (SHAM) group served as controls. The levels of oxidized and reduced glutathione (GSSG, GSH) were followed from blood samples drawn fortnightly.

Results

During the follow-up, the ratios GSSG/GSH showed similar trends in both DA groups, levels being significantly lower than those in the SHAM group at weeks 8 and 10. GSSG levels were lower than the baseline throughout the study in all groups except for NX controls. The GSH levels were increased in all three NX groups (weeks 6–10) compared with both the baseline and the SHAM group

Conclusion

Our results suggest that the extent of oxidative stress is similar in response to different dosing regimens of DA in 5/6 NX rats when comparable hemoglobin levels are maintained. These findings remain to be confirmed in chronic kidney disease patients.     

Genetic basis of non-syndromic anomalies of human tooth number

Teeth organogenesis develops through a well-ordered series of inductive events involving genes and BMP, FGF, SHH and WNT represent the main signalling pathways that regulate epithelial-mesenchymal interactions. Moreover, progress in genetics and molecular biology indicates that more than 300 genes are involved in different phases of teeth development. Mutations in genes involved in odontogenesis are responsible for many dental anomalies, including a number of dental anomalies that can be associated with other systemic skeletal or organic manifestations (syndromic dental anomalies) or not (non-syndromic dental anomalies). The knowledge of the genetic development mechanisms of the latter is of major interest. Understanding the mechanisms of pathogenesis of non-syndromic teeth anomalies would also clarify the role of teeth in craniofacial development, and this would represent an important contribution to the diagnosis, treatment and prognosis of congenital malformations, and the eventual association to other severe diseases. Future research in this area is likely to lead to the development of tests for doctors to formulate an early diagnosis of these anomalies.     

Effect of maxillary sinus floor augmentation on sinus membrane thickness in computed tomography

Background: Little is known about maxillary sinus compliance, i.e., the intrinsic potential of the sinus membrane to resume its homeostatic status after the surgical trauma caused by sinus floor elevation. The aim of the present study is to investigate the effect of maxillary sinus floor augmentation on sinus membrane thickness. Methods: Within‐patient comparison of computed tomographic scans before bone grafting versus 4 to 6 months after bone grafting was performed. Changes in membrane thickness were evaluated in 65 maxillary sinus floor augmentation procedures via a lateral approach in 35 patients without clinical signs of sinus pathology at any time. Results: Sinus membrane thickness differed significantly before (0.8 ± 1.2 mm) versus after (1.5 ± 1.3 mm) augmentation surgery (P <0.001), with a mean increase of 0.8 ± 1.6 mm (maximum: 4.4 mm). Only 28% of augmented sinuses did not show membrane thickening. In non‐augmented control sinuses, there was no evidence of membrane thickness increase. Conclusions: The results indicate that the maxillary sinus membrane, even in healthy clinical conditions, undergoes morphologic modifications after sinus floor elevation, yet membrane reactions demonstrate significant variability. Future research on the effect of augmentation surgery on maxillary sinus physiology is recommended.     

Oscillatory support for rapid frequency change processing in infants

Rapid auditory processing and auditory change detection abilities are crucial aspects of speech and language development, particularly in the first year of life. Animal models and adult studies suggest that oscillatory synchrony, and in particular low-frequency oscillations play key roles in this process. We hypothesize that infant perception of rapid pitch and timing changes is mediated, at least in part, by oscillatory mechanisms. Using event-related potentials (ERPs), source localization and time-frequency analysis of event-related oscillations (EROs), we examined the neural substrates of rapid auditory processing in 4-month-olds. During a standard oddball paradigm, infants listened to tone pairs with invariant standard (STD, 800–800 Hz) and variant deviant (DEV, 800–1200 Hz) pitch. STD and DEV tone pairs were first presented in a block with a short inter-stimulus interval (ISI) (Rapid Rate: 70 ms ISI), followed by a block of stimuli with a longer ISI (Control Rate: 300 ms ISI). Results showed greater ERP peak amplitude in response to the DEV tone in both conditions and later and larger peaks during Rapid Rate presentation, compared to the Control condition. Sources of neural activity, localized to right and left auditory regions, showed larger and faster activation in the right hemisphere for both rate conditions. Time-frequency analysis of the source activity revealed clusters of theta band enhancement to the DEV tone in right auditory cortex for both conditions. Left auditory activity was enhanced only during Rapid Rate presentation. These data suggest that local low-frequency oscillatory synchrony underlies rapid processing and can robustly index auditory perception in young infants. Furthermore, left hemisphere recruitment during rapid frequency change discrimination suggests a difference in the spectral and temporal resolution of right and left hemispheres at a very young age.     

Theta responses are abnormal in mild cognitive impairment: evidence from analysis of theta event-related synchronization during a temporal expectancy task

We examined the hypothesis that the attention/executive deficits in mild cognitive impairment (MCI) due to Alzheimer’s disease is associated to an abnormal cortical activation, revealed by the method of event-related synchronization/desynchronization (ERS/ERD) in the theta band during a paradigm of temporal orienting of attention. MCI patients (n = 25) and healthy elderly (HE) matched controls (n = 15) performed a task in which periodically omitted tones had to be predicted and their virtual onset time had to be marked by pressing a button. Single-trial theta responses were measured, respectively, before and after the motor response. Then, theta responses were compared to theta power during eyes closed resting state (ERD/ERS method).The temporal course of the task was characterized by two different behavioural conditions: (1) a pre-event epoch, in which the subject awaited the virtual onset of the omitted tone, (2) a post-event (after button pressing) epoch, in which the subject was in a post-motor response condition. The most important findings are summarized as follows: (1) in both groups, the pre-event epoch was characterized by theta ERS on temporal electrodes, but HE had a greater theta ERS compared to that of MCI group; (2) in both groups, during the post-motor condition, there was a theta ERS on prefrontal regions, and, also in this case, HE showed a greater theta enhancement compared to that of MCI patients; (3) HE showed evidence of lateralization: during the waiting epoch, theta ERS was dominant on the right posterior temporal lead (T6), whilst, during the post-motor epoch, theta ERS was greater on the left, as well as the midline prefrontal leads. Compared to the traditional neuropsychological measures for the episodic memory, these theta ERS indicators were less accurate in differentiating MCI patients from healthy elderly. The clinical relevance of these findings is that the weaker theta reactivity in MCI would indicate an early impairment in the temporal orienting of attention in the early stage of the clinical course of this neurodegenerative disease.     

Food is Never Enough: Nature and Nurture's Influence on Children's Food Dose Evaluation

This study investigated whether if socioeconomic factors and\or food palatability influence food amount evaluation among children. Ninety-four children, 10–15 years old, living in Mali in Africa, and 124 living in northern Italy were asked to evaluate an amount of palatable and non palatable candies. The evaluations were compared both to the real number of candies and to that given by the other group. Both Italian and Malian children underestimated the edible candies, interestingly however Malian children did not underestimate altered candies. The data suggest that food dose underestimation is a transcultural characteristic. Evaluation of palatable food is not influenced by socio cultural factors. Underestimation could be a biological protective factor against food shortage; in case of food abundance it could play a role in onset and maintenance of obesity.     

Affective Judgment and Physical Activity in Youth: Review and Meta-Analyses

Background

A recent meta-analysis on affective judgment and physical activity in adults yielded a medium effect-sized relationship. Despite narrative reviews and topic interest, a meta-analysis in youth has not yet been conducted.

Purpose

This study aims to appraise the overall effect of affective judgment on physical activity in youth via meta-analyses and explore moderators of this relationship.

Methods

Literature searches were conducted between 1990 and 2011. Fixed and random effects meta-analysis with correction for sampling, measurement, and publication bias were employed.

Results

Fifty-six correlational studies and 14 interventions met the inclusion criteria. Among correlational studies, the corrected summary r was 0.26 (95 % CI 0.18–0.32). Significant moderators were gender, measure of physical activity, and recruitment context. Among intervention studies, Cohen’s d was 0.25 (95 % CI 0.11–0.40).

Conclusions

The results are close to a medium effect size which is larger than other meta-analytic physical activity correlates among youth. The construct should be included in our contemporary theories for understanding and intervening upon youth physical activity.