Magnetic Resonance Imaging-Guided Needle Insertion Robots: A Review of Systems for Liver and Kidney Interventions

Magnetic resonance imaging (MRI)-guided intervention for the liver and kidney has achieved considerable progress in tumor diagnosis and treatment over the past two decades. However, due to the space constraints associated with the narrow and deep bore of MRI machines, it is still extremely challenging for clinicians to position and drive the needle-shaped probes used for delivering the treatment where the targeted tumoral mass is located. MRI-compatible robotic systems have been investigated by several research teams worldwide, both in academia and industry. These endeavors aim to address challenges related to the confined workspace within MRI machine bores. The goal is to facilitate the shift from computed tomography (CT)-guided to MRI-guided interventions, leveraging the advantages of MRI, including its exceptional soft tissue contrast, nonionizing radiation, and versatile multiangle imaging capabilities. In this article, we systematically review the state-of-the-art MRI-guided needle insertion robots for the treatment of the liver and kidney in order to identify challenges, trends, and potential research gaps in this field. Furthermore, this review encompasses robotic systems designed for anatomically similar regions or exhibiting comparable structures to those intended for interventions in the liver and kidney. These systems, which have shown potential for application in this field, are discussed to explore possibilities within this domain. The review concludes by proposing future research directions in this area

Snf2h Primes UL Neuron Production

Alterations in the homeostasis of either cortical progenitor pool, namely the apically located radial glial (RG) cells or the basal intermediate progenitors (IPCs) can severely impair cortical neuron production. Such changes are reflected by microcephaly and are often associated with cognitive defects. Genes encoding epigenetic regulators are a frequent cause of intellectual disability and many have been shown to regulate progenitor cell growth, including our inactivation of the Smarca1 gene encoding Snf2l, which is one of two ISWI mammalian orthologs. Loss of the Snf2l protein resulted in dysregulation of Foxg1 and IPC proliferation leading to macrocephaly. Here we show that inactivation of the closely related Smarca5 gene encoding the Snf2h chromatin remodeler is necessary for embryonic IPC expansion and subsequent specification of callosal projection neurons. Telencephalon-specific Smarca5 cKO embryos have impaired cell cycle kinetics and increased cell death, resulting in fewer Tbr2+ and FoxG1+ IPCs by mid-neurogenesis. These deficits give rise to adult mice with a dramatic reduction in Satb2C upper layer neurons, and partial agenesis of the corpus callosum. Mice survive into adulthood but molecularly display reduced expression of the clustered protocadherin genes that may further contribute to altered dendritic arborization and a hyperactive behavioral phenotype. Our studies provide novel insight into the developmental function of Snf2h-dependent chromatin remodeling processes during brain development

An MR Safe Double-Arch Needle Insertion Robot with Scissor-Folding Mechanism for Abdominal Percutaneous Interventions*

Tumors affecting abdominal organs rank among the deadliest malignancies. In this context, Magnetic Resonance Imaging (MRI) serves as an effective diagnostic tool with a strong potential to support image-guided minimally invasive interventions for treating these tumours, offering an ionizing-radiation-free medical modality. MRI provides exceptional soft tissue contrast and multi-angle imaging, enabling accurate intraoperative localisation of target tumours within these vital organs. Nevertheless, MRI-guided minimally invasive interventions still encounter significant challenges due to the strong magnetic field environment and the narrow and deep bore of MRI machines. This paper proposes a novel MR safe 5-degrees-of-freedom (DoFs) parallel table-mounted double-arch needle insertion robot with a scissor-folding mechanism (SFM) for abdominal interventions. The proposed robot is designed to fit a standard 70-cm MRI bore. Initial evaluation experiments indicate mean errors of 3.14 mm for the proposed robotic arch and 2.23 mm for the full needle insertion robot, respectively. Additionally, preliminary testing of the system in an MRI environment resulted in unaltered MRI imaging output, with negligible artefacts associated with the presence of the robot within the bore

Particulate Trace Metal Sources, Cycling, and Distributions on the Southwest African Shelf

We present labile (L-pTM) and refractory (R-pTM) particulate trace metal distributions of Fe, Mn, Al, Ti, Co, Zn, Cd, Ni, Pb, Cu, and P for a transect along the southwest African shelf and an off-shore section at 3°S of the GEOTRACES GA08 section cruise. Particle sources and biogeochemical cycling processes are inferred using particle-type proxies and elemental ratios. Enhanced concentrations of bio-essential L-pTMs (Zn, Cu, Ni, Cd, Co, and P) were observed in the Benguela upwelling region, attributed to enhanced primary production. Bio-essential pTM stoichiometric ratios (normalized to pP) were consistent with phytoplankton biomass across the transect, except for Fe and Mn, which included adsorbed and labile oxide phases. Low pP lability (∼41%) suggests a potential refractory biogenic source on the Benguela shelf. Variable labilities observed between stations along the transect indicated potentially different biogenic pP labilities among different plankton groups. Benthic resuspension was prevalent in (near-)bottom waters along the transect and formed an important source of Fe and Mn oxides. Lithogenic particles along the entire shelf were Mn deficient and particles on the Benguela shelf were enriched in Fe, consistent with regional sediment compositions. Enhanced available-Fe (dissolved + labile particulate Fe) concentrations (up to 39.6 nM) were observed in oxygen-deficient (near-)bottom waters of the Benguela shelf coinciding with low L-pMn. This was attributed to the faster oxidation kinetics of Fe, allowing Fe-oxide precipitation and retention on the shelf, while Mn oxidation was slower. Enhanced L-pFe in the Congo River plume, which comprised as much as 93% of the available-Fe pool, was attributed to increased scavenging and formation of Fe oxides. Increased scavenging of other particle-reactive trace metals (TMs) (Mn, Al, and Pb) was also apparent in Congo-influenced waters. However, particles did not play a significant role in transporting TMs off-shelf within Congo plume waters. Key Points: • Different oxidation kinetics lead to decoupled Fe and Mn oxide redox cycling within oxygen-depleted waters on the Benguela Shelf • Lower lability of particulate phosphorus (∼41%) indicate potential refractory biogenic source on Benguela shelf • Nepheloid particles formed important sources of Fe and Mn oxides that adsorb trace metals (TMs), and serve as potential TM sources from shelf to open ocea

Voluntary Running Triggers VGF-Mediated Oligodendrogenesis to Prolong the Lifespan of Snf2h-Null Ataxic Mice

SummaryExercise has been argued to enhance cognitive function and slow progressive neurodegenerative disease. Although exercise promotes neurogenesis, oligodendrogenesis and adaptive myelination are also significant contributors to brain repair and brain health. Nonetheless, the molecular details underlying these effects remain poorly understood. Conditional ablation of the Snf2h gene impairs cerebellar development producing mice with poor motor function, progressive ataxia, and death between postnatal days 25–45. Here, we show that voluntary running induced an endogenous brain repair mechanism that resulted in a striking increase in hindbrain myelination and the long-term survival of Snf2h cKO mice. Further experiments identified the VGF growth factor as a major driver underlying this effect. VGF neuropeptides promote oligodendrogenesis in vitro, whereas Snf2h cKO mice treated with full-length VGF-encoding adenoviruses removed the requirement of exercise for survival. Together, these results suggest that VGF delivery could represent a therapeutic strategy for cerebellar ataxia and other pathologies of the CNS

Data_Sheet_1_Snf2h Drives Chromatin Remodeling to Prime Upper Layer Cortical Neuron Development.docx

Alterations in the homeostasis of either cortical progenitor pool, namely the apically located radial glial (RG) cells or the basal intermediate progenitors (IPCs) can severely impair cortical neuron production. Such changes are reflected by microcephaly and are often associated with cognitive defects. Genes encoding epigenetic regulators are a frequent cause of intellectual disability and many have been shown to regulate progenitor cell growth, including our inactivation of the Smarca1 gene encoding Snf2l, which is one of two ISWI mammalian orthologs. Loss of the Snf2l protein resulted in dysregulation of Foxg1 and IPC proliferation leading to macrocephaly. Here we show that inactivation of the closely related Smarca5 gene encoding the Snf2h chromatin remodeler is necessary for embryonic IPC expansion and subsequent specification of callosal projection neurons. Telencephalon-specific Smarca5 cKO embryos have impaired cell cycle kinetics and increased cell death, resulting in fewer Tbr2+ and FoxG1+ IPCs by mid-neurogenesis. These deficits give rise to adult mice with a dramatic reduction in Satb2+ upper layer neurons, and partial agenesis of the corpus callosum. Mice survive into adulthood but molecularly display reduced expression of the clustered protocadherin genes that may further contribute to altered dendritic arborization and a hyperactive behavioral phenotype. Our studies provide novel insight into the developmental function of Snf2h-dependent chromatin remodeling processes during brain development.</p