Reprogramming suppresses premature senescence phenotypes of Werner syndrome cells and maintains chromosomal stability over long-term culture

Werner syndrome (WS) is a premature aging disorder characterized by chromosomal instability and cancer predisposition. Mutations in WRN are responsible for the disease and cause telomere dysfunction, resulting in accelerated aging. Recent studies have revealed that cells from WS patients can be successfully reprogrammed into induced pluripotent stem cells (iPSCs). In the present study, we describe the effects of long-term culture on WS iPSCs, which acquired and maintained infinite proliferative potential for self-renewal over 2 years. After long-term cultures, WS iPSCs exhibited stable undifferentiated states and differentiation capacity, and premature upregulation of senescence-associated genes in WS cells was completely suppressed in WS iPSCs despite WRN deficiency. WS iPSCs also showed recapitulation of the phenotypes during differentiation. Furthermore, karyotype analysis indicated that WS iPSCs were stable, and half of the descendant clones had chromosomal profiles that were similar to those of parental cells. These unexpected properties might be achieved by induced expression of endogenous telomerase gene during reprogramming, which trigger telomerase reactivation leading to suppression of both replicative senescence and telomere dysfunction in WS cells. These findings demonstrated that reprogramming suppressed premature senescence phenotypes in WS cells and WS iPSCs could lead to chromosomal stability over the long term. WS iPSCs will provide opportunities to identify affected lineages in WS and to develop a new strategy for the treatment of WS.

Trend figures assist with untrained emergency electroencephalogram interpretation

OBJECTIVE

Acute electroencephalogram (EEG) findings are important for diagnosing emergency patients with suspected neurological disorders, but they can be difficult for untrained medical staff to interpret. In this research, we will develop an emergency EEG trend figure that we hypothesize will be more easily understood by untrained staff compared with the raw original traces.

METHODS

For each of several EEG patterns (wakefulness, sleep, seizure activity, and encephalopathy), trend figures incorporating information on both amplitude and frequency were built. The accuracy of untrained reviewers' interpretation was compared with that of the raw EEG trace interpretation.

RESULTS

The rate of correct answers was significantly higher in response to the EEG trend figures than to the raw traces showing wakefulness, sleep, and encephalopathy, but there was no difference when seizure activity patterns were viewed. The rates of misjudging normal or abnormal findings were significantly lower with the trend figures in the wakefulness pattern; in the other patterns, misjudgments were equally low for the trend figures and the raw traces.

CONCLUSION

EEG trend figures improved the accuracy with which untrained medical staff interpreted emergency EEGs. Emergency EEG figures that can be understood intuitively with minimal training might improve the accuracy of emergency EEG interpretation. However, additional studies are required to confirm these results because there may be many types of clinical EEGs that are difficult to interpret.

Risk factors for sedation and MRI failure in children with neurodevelopmental disorders undergoing head MRI with oral triclofos sodium and/or rectal chloral hydrate

BACKGROUND

Head magnetic resonance imaging (MRI) is of critical importance in the diagnosis and management of neurodevelopmental disorders. However, the use of sedation in affected children can present a significant challenge.

AIMS

To identify the factors associated with sedation and MRI failure in children with neurodevelopmental disorders undergoing head MRI with oral triclofos sodium or rectal chloral hydrate.

METHODS

This retrospective study analyzed 215 MRI sessions of children with neurodevelopmental disorders from January 2020 to December 2021. Sedation was administered via oral triclofos sodium or rectal chloral hydrate. Multivariate logistic regression was used to determine the factors associated with sedation failure and MRI failure.

RESULTS

The sedation failure rate was 38.1 % (82/215). Factors significantly associated with sedation failure were older age (odds ratio [OR] 1.59, 95 % confidence interval [CI] 1.30-1.95, p < 0.001) and stranger anxiety (OR 4.07, 95 % CI 1.95-8.49, p < 0.001). The age cut-off for increased sedation failure risk was 4.0 years (p < 0.01). The MRI failure rate was 21.9 % (47/215), associated with autism spectrum disorder (ASD) diagnosis (OR 19.00, 95 % CI 2.43-149.00, p < 0.01), stranger anxiety (OR 3.66, 95 % CI 1.62-8.24, p < 0.01), and place anxiety (OR 3.18, 95 % CI 1.33-7.57, p < 0.01).

CONCLUSIONS

Older age and stranger anxiety are significant risk factors for sedation failure, while ASD diagnosis, stranger anxiety, and place anxiety increase MRI failure risk in children with neurodevelopmental disorders undergoing head MRI.

Spatiotemporal expression pattern of dyslexia susceptibility 1 candidate 1 (DYX1C1) during rat cerebral cortex development

BACKGROUND

Developmental dyslexia (DD) is a common learning disorder with significant consequences for affected individuals. Although several candidate genes, including dyslexia susceptibility 1 candidate 1 (DYX1C1), have been implicated in dyslexia, their role in brain development remains unclear. We aimed to elucidate the spatiotemporal expression patterns of DYX1C1 during cerebral cortex development in rats.

METHODS

We investigated DYX1C1 expression during cerebral cortex development using rat embryos at various gestational stages (E13.5, 15.5, 17.5 and 20.5) by immunohistochemistry (n = 7 embryos/stage), quantitative real-time PCR (n = 6), and in situ hybridization (n = 11-15).

RESULTS

The DYX1C1-positive cells were predominantly located in the outermost layers of the cortical plate, particularly at E15.5. DYX1C1 mRNA expression peaked at E15.5 and subsequently declined. DYX1C1-positive cells did not co-localize with reelin-positive Cajal-Retzius cells, but co-localized with neuronal markers expressed during development, and had shorter primary cilia than DYX1C1-negative cells.

CONCLUSIONS

Our findings highlight the dynamic expression of DYX1C1 in the developing cerebral cortex of rats, implicating its involvement in neurodevelopmental processes. Further investigation of the functional interactions of DYX1C1, particularly its relationship with reelin and its role in cerebrocortical and hippocampal development, may provide insights into the pathophysiology of dyslexia and neurodevelopmental disorders.

IMPACT

Our study elucidates spatiotemporal expression patterns of endogenous DYX1C1 predominantly in the primitive cortical zone (PCZ), outermost layer of the cortical plate (CP) during cerebral cortex development, particularly peaked at E15.5. We revealed the spatial relationship between DYX1C1-positive and reelin-expressing Cajal-Retzius (CR) cells, and co-localize with neuronal markers expressed during cerebral cortex development, indicating its contribution to neuronal migration and cortical layer formation. DYX1C1-positive cells mainly in the PCZ possess shorter primary cilia than DYX1C1-negative cells, suggesting the completion of migration.

Prolonged Capillary Refill Time as an Early Sign of Compromised Circulation in an Infant With Supraventricular Tachycardia: A Case Report

Capillary refill time (CRT) is a valuable clinical sign in pediatric assessment, particularly in evaluating circulatory status. We present a case of a one-month-old infant with supraventricular tachycardia (SVT), who demonstrated prolonged CRT, emphasizing the importance of this physical examination finding in the context of other signs of compromised circulation.