Targeted in vivo mutagenesis of a sensor histidine kinase playing an essential role in ABA signaling of the moss Physcomitrium patens.

Land plants exhibit various adaptation responses to unfavorable water environments, such as drought and flooding. The phytohormone abscisic acid (ABA) and ethylene play essential roles in plant adaptation to drought and flooding, respectively. It remains largely unknown how plants integrate environmental information for water availability. In the moss Physcomitrium patens, we recently reported that not only ethylene/flooding signaling but also ABA/osmostress signaling are mediated by ethylene receptor-related sensor histidine kinases (ETR-HKs). Subfamily I ETR-HKs of this moss were found to interact with a RAF kinase (ARK) and were required for ABA-dependent activation of SNF1-related protein kinase 2 (SnRK2) via ARK activation. To elucidate the mechanisms of ARK regulation by ETR-HKs, here we employed targeted in vivo mutagenesis of PpHK5, a member of subfamily I ETR-HKs. Analyses of ABA-insensitive Pphk5 mutants indicated that PpHK5 mutations affecting the interaction with ARK resulted in loss of PpHK5 function to activate ABA signaling. We also identified a PpHK5 mutation that does not affect ARK interaction but resulted in loss of PpHK5 function. These results suggest that physical interaction between ETR-HK and ARK is essential but not sufficient for the regulation of ARK activity, and the C-terminal response regulator domain is involved in regulating ARK activation.

Dural substitutes for spina bifida repair: past, present, and future.

PURPOSE: The use of materials to facilitate dural closure during spina bifida (SB) repair has been a highly studied aspect of the surgical procedure. The overall objective of this review is to present key findings pertaining to the success of the materials used in clinical and pre-clinical studies. Additionally, this review aims to aid fetal surgeons as they prepare for open or fetoscopic prenatal SB repairs. METHODS: Relevant publications centered on dural substitutes used during SB repair were identified. Important information from each article was extracted including year of publication, material class and sub-class, animal model used in pre-clinical studies, whether the repair was conducted pre-or postnatally, the bioactive agent delivered, and key findings from the study. RESULTS: Out of 1,121 publications, 71 were selected for full review. We identified the investigation of 33 different patches where 20 and 63 publications studied synthetic and natural materials, respectively. From this library, 43.6% focused on clinical results, 36.6% focused on pre-clinical results, and 19.8% focused on tissue engineering approaches. Overall, the use of patches, irrespective of material, have shown to successfully protect the spinal cord and most have shown promising survival and neurological outcomes. CONCLUSION: While most have shown significant promise as a therapeutic strategy in both clinical and pre-clinical studies, none of the patches developed so far are deemed perfect for SB repair. Therefore, there is an opportunity to develop new materials and strategies that aim to overcome these challenges and further improve the outcomes of SB patients.

Comparison of two- and three-dimensional endoscopic visualization for fetal myelomeningocele repair: a pilot study using a fetoscopic surgical simulator.

INTRODUCTION: The objective of this study was to evaluate the utility of three-dimensional (3D) versus conventional two-dimensional (2D) endoscopy for fetal myelomeningocele repair using a low-fidelity fetoscopic surgical simulator. METHODS: A low-fidelity fetoscopic box trainer was developed for surgical simulation of myelomeningocele repair. Participants with varying surgical experience were recruited and completed three essential tasks (cutting skin, dural patch placement, and suturing skin) using both 2D and 3D endoscopic visualization. Participants were randomized to begin all tasks in either 2D or 3D. Time to completion was measured for each task, and each participant subsequently completed the NASA Load Index test and a questionnaire evaluating their experience. RESULTS: Sixteen participants completed the study tasks using both 2D and 3D endoscopes in the simulator. While the mean performance time across all tasks was shorter with 3D versus 2D endoscopy (cutting skin, 47 vs. 54 seconds; dural patch placement, 38 vs. 52 seconds; and suturing skin, 424 vs. 499 seconds), the results did not reach statistical significance. When comparing times to completion of each of the three tasks between levels of expertise, participants in the expert category were faster when suturing skin on the 2D modality (P = 0.047). Under 3D visualization, experts were faster at cutting the skin (P = 0.008). When comparing experiences using the NASA-TLX test, participants felt that their performance was better using 3D over the 2D system (P = 0.045). Overall, 13 of 16 (81.3%) participants preferred 3D over 2D visualization. CONCLUSIONS: Three-dimensional endoscopes could potentially be used in the near future for relative improvement in visualization and possibly performance during complex fetoscopic procedures such as prenatal repair of myelomeningocele defects. Further studies utilizing 3D scopes for other related procedures may potentially support clinical implementation of this technology in fetal surgery and also prove to be a useful tool in surgical training.

Fetal brain damage in congenital hydrocephalus.

BACKGROUND: Congenital hydrocephalus (HCP) is a developmental brain disorder characterized by the abnormal accumulation of cerebrospinal fluid within the ventricles. It is caused by genetic and acquired factors that start during early embryogenesis with disruption of the neurogerminal areas. As might be expected, early-onset hydrocephalus alters the process of brain development leading to irreparable neurological deficit. A primary alteration of the ependyma/neural stem cells (affecting vesicle trafficking and abnormal cell junctions) leads to its loss or denudation and translocation of neural progenitor cells (NPCs) and neural stem cells (NSCs) into the cerebrospinal fluid (CSF). Under these abnormal conditions, morphological and functional processes, underlying the concept of astroglial reaction, are initiated in an attempt to recover homeostasis in the periventricular zone. This astroglial reaction includes astrocyte hypertrophy, hyperplasia, and development of a new layer with reorganized functional features that resemble the ependyma. Despite decades of research, there is a lack of information concerning the biological basis of the brain abnormalities that are associated with HCP. DISCUSSION: The present review of current literature discusses the neuropathological changes during gestation following the onset of congenital hydrocephalus and the unanswered questions into the pathophysiology of the disease. A better understanding of those missing points might help create novel therapeutic strategies that can reverse or even prevent the ultimate neurological impairment that affects this population and improve long-term clinical outcome.

Myasthenia as a paraneoplastic manifestation of ovarian Cancer.

We describe the first case of myasthenia gravis as a possible paraneoplastic manifestation of ovarian cancer preceding its diagnosis.