Percutaneous Full Endoscopic Management of Spinal Foraminal Schwannomas: Case Series.

BACKGROUND: Schwannoma, a benign peripheral nerve sheath tumor, is perhaps only secondary to degenerative pathology as the most common lesion at neural foramen. The surgical dilemma here is either risking nerve injury because of inadequate exposure or the need for internal fixation because of facet joint sacrifice. OBJECTIVE: To evaluate the feasibility and safety of management of foraminal schwannomas by percutaneous full-endoscopic technique. METHODS: A single-center retrospective review was conducted on patients who underwent full-endoscopic resection of neural foraminal schwannomas. Tumors were grouped into either medial type or lateral type based on relevant location to the neural foramen, and respective surgical approaches were adopted. Data including preoperative neurological status, tumor size, surgery time, the extension of resection, and clinical outcomes were collected. The learning curve was plotted as surgical time/tumor size against case number. RESULTS: A total of 25 patients were treated between May 2015 and March 2022. Gross total resection was achieved in 24 patients, and near-total resection in 1 case, with 1 patient experienced transient voiding difficulty. No tumor recurrence or spinal instability was detected in the short-term follow-up (median follow-up 22 months, range 3 months-6 years). Surgical efficiency improved with the number of cases operated on and remained stable after the initial 10 cases. CONCLUSION: Percutaneous full-endoscopic technique is a safe and minimally invasive technique for the resection of foraminal schwannomas.

[Differentiation of embryonic stem cells from the embryos of the couples with male asthenozoospermia and Robertsonian translocation into germ cells].

OBJECTIVE: To assess the risk of male infertility in the offspring conceived through assisted reproductive technology (ART) byin vitroinductionof the differentiation of embryonic stem cells (ESCs) derived from the embryos of the couples with male asthenozoospermia and Robertsonian translocation (RT) into germ cells. METHODS: We established a CCRM16ESC line with the karyotype of 46, XY, +14, rob(13; 14) (q10; q10) from the embryo donated by a patientwithasthenozoospermiaand RT and his wife by isolation of the inner cell mass of blastula, culturing, passaging, and amplification,followed by in vitro induction and differentiationof the ESCs into germ cells with ratinoic acid(RA) at 2 mol/L. Then, we analyzed the process of differentiation and the expressions of its related genes and compared them with those in the normal CCRM23ESCs. RESULTS: CCRM16 showed the typical characteristics of ESCs, expressing the pluripotency makers of NANOG, OCT4, TRA-1-181 and SSEA4, forming embryoid bodies, and differentiating into three germlayer tissues in vitro and in vivo. Intervention with 2 mol/LRAinduced direct differentiation of the ESCs into germ cells. The expressions of the primordial germ cell marker geneDAZLand the meiosis marker geneSCP3were markedly decreased in the CCRM16 as compared with those in the normal CCRM23 ESCs. CONCLUSIONS: The CCRM16ESC linewith the karyotype of46, XY, +14, rob(13; 14) (q10; q10) has thetypical characteristics of ESCs but an abnormal process of differentiation into germ cells in the early stage. In vitroinductionof the differentiation of ESCs into germ cells can be used for assessing the risk of male infertility in the offspring conceived through ART for asthenozoospermia patients.

Minimally invasive removal of lumbar intradural extramedullary lesions using the interlaminar approach.

OBJECT Posterior midline laminectomy or hemilaminectomy has been successfully applied as the standard microsurgical technique for the treatment of spinal intradural pathologies. However, the associated risks of postoperative spinal instability increase the need for subsequent fusion surgery to prevent potential long-term spinal deformity. Continuous efforts have been made to minimize injuries to the surrounding tissue resulting from surgical manipulations. The authors report here their experiences with a novel minimally invasive surgical approach, namely the interlaminar approach, for the treatment of lumbar intraspinal tumors. METHODS A retrospective review was conducted of patients at the Second Affiliated Hospital of Zhejiang University School of Medicine who underwent minimally invasive resection of lumbar intradural-extramedullary tumors. By using an operative microscope, in addition to an endoscope when necessary, the authors were able to treat all patients with a unilateral, paramedian, bone-sparing interlaminar technique. Data including preoperative neurological status, tumor location, size, pathological diagnosis, extension of resections, intraoperative blood loss, length of hospital stay, and clinical outcomes were obtained through clinical and radiological examinations. RESULTS Eighteen patients diagnosed with lumbar intradural-extramedullary tumors were treated from October 2013 to March 2015 by this interlaminar technique. A microscope was used in 15 cases, and the remaining 3 cases were treated using a microscope as well as an endoscope. There were 14 schwannomas, 2 ependymomas, 1 epidermoid cyst, and 1 enterogenous cyst. Postoperative radiological follow-up revealed complete removal of all the lesions and no signs of bone defects in the lamina. At clinical follow-up, 14 of the 18 patients had less pain, and patients' motor/sensory functions improved or remained normal in all cases except 1. CONClUSIONS When meeting certain selection criteria, intradural-extramedullary lumbar tumors, especially schwannomas, can be completely and safely resected through a less-invasive interlaminar approach using a microscope, or a microscope in addition to an endoscope when necessary. This approach was advantageous because it caused even less bone destruction, resulting in better postoperative spinal stability, no need for facetectomy and fusion, and quicker functional recovery for the patients. Individualized surgical planning according to preoperative radiological findings is key to a successful microsurgical resection of these lesions through the interlaminar space.

Hippocampal NR2B-containing NMDA receptors enhance long-term potentiation in rats with chronic visceral pain.

Pain and learning memory have striking similarities in synaptic plasticity. Activation of the N-methyl-D-aspartic acid receptors 2B subunits (NR2B-NMDAs) is responsible for the hippocampal LTP in memory formation. In our previous studies, we found the significant enhancement of CA1 hippocampal long-term potentiation (LTP) induced by high-frequency stimulation (HFS) in rats with chronic visceral pain. However, it is unclear whether the NR2B-NMDAs are required for the LTP in chronic visceral pain. In this study, a rat model with irritable bowel syndrome (IBS) was established by colorectal distention (CRD). The sensitivity of visceral pain and HFS-induced LTP at SC-CA1 synapses were significantly enhanced in IBS-like rats (p<0.05). In addition, hippocampal NR2B protein levels significantly increased in IBS-like rats (p<0.05). To test whether NR2B-NMDAs are responsible for the LTP, effects of Ro 25-6981, a selective antagonist of NR2B-NMDAs, on field potential in CA1 region were investigated in vitro. Our results demonstrated that Ro 25-6981 dose-dependently inhibited the facilitation of CA1 LTP in IBS-like rats. The plausible activation mechanism of hippocampal NR2B-NMDAs in the LTP enhancement was further explored. Western blot data indicated that expression of tyrosine phosphorylated NR2B protein in hippocampus significantly enhanced in IBS-like rats. Accordingly, genistein, a specific inhibitor of tyrosine kinases, dose-dependently blocked the facilitation of hippocampal LTP in IBS-like rats. Furthermore, EMG data revealed that intra-hippocampal injection of Ro 25-6981 dose-dependently attenuated the visceral hypersensitivity. In conclusion, hippocampal NR2B-NMDAs are responsible for the facilitation of CA1 LTP via tyrosine phosphorylation, which leads to visceral hypersensitivity.

ZD 7288, an HCN channel blocker, attenuates chronic visceral pain in irritable bowel syndrome-like rats.

AIM: To investigate the effects of ZD 7288, a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, on rats with chronic visceral pain. METHODS: Rats with visceral hypersensitivity were generated using neonatal colon irritation during postnatal days 8-15 as described previously. Visceral hypersensitivity was evaluated using electromyographic (EMG) responses of abdominal external oblique muscles to 20-80 mmHg colorectal distentions (CRD). Abdominal withdrawal reflex (AWR) scores and pain thresholds were also detected in adult rats. Different doses of ZD 7288 (25, 50, and 100 nmol/L) were intrathecally administered in rats to study the role of spinal HCN channel in chronic visceral hypersensitivity. RESULTS: EMG responses to 20-80 mmHg CRD and AWR scores under 20-60 mmHg CRD significantly increased in rats with visceral hypersensitivity compared to control rats (P < 0.05). The pain threshold in rats with visceral hypersensitivity significantly decreased compared to control rats (P < 0.05). Treatment with 50-100 nmol/L ZD 7288 significantly inhibited EMG responses (16%-62%, 80-20 mmHg CRD, P < 0.05) and AWR scores (24%-37%, 40-20 mmHg CRD, P < 0.05; 12%-61%, 80-20 mmHg CRD, P < 0.05, respectively), and significantly increased pain thresholds (32%-77%, P < 0.05). CONCLUSION: Spinal HCN channels may play an important role in chronic visceral hypersensitivity.

Tyrosine phosphorylation of the NR2B subunit of the NMDA receptor in the spinal cord contributes to chronic visceral pain in rats.

The roles of spinal N-methyl-d-aspartic acid receptor 2B (NR2B) subunit in central sensitization of chronic visceral pain were investigated. A rat model with irritable bowel syndrome (IBS) was established by colorectal distention (CRD) on post-natal days 8-14. Responses of the external oblique muscle of the abdomen to CRD were measured to evaluate the sensitivity of visceral pain in rats. The sensitivity of visceral pain significantly increased in IBS-like rats. Expressions of spinal NR2B subunit and phosphorylated NR2B subunit significantly increased by 50-55% in IBS-like rats when compared with those in control rats. Ro 25-6981, a selective antagonist of NR2B subunit, has a dose-dependent anti-allodynic and anti-hyperalgesic effect without causing motor dysfunction in IBS-like rats. Furthermore, the activation mechanism of the spinal NR2B subunit in chronic visceral pain was also investigated. Spinal administration of genistein, a specific inhibitor of tyrosine kinases, also decreased the visceral pain hypersensitivity of IBS-like rats in a dose-dependent manner. In addition, the expression of phosphorylated NR2B subunit was decreased after spinal administration of Ro 25-6981 or genistein in IBS-like rats. In conclusion, tyrosine kinase activation-induced phosphorylation of NR2B subunit may play a crucial role in central sensitization of chronic visceral pain.

Tripchlorolide improves age-associated cognitive deficits by reversing hippocampal synaptic plasticity impairment and NMDA receptor dysfunction in SAMP8 mice.

Deficits in cognition and performance accompanying age-related neurodegenerative diseases such as Alzheimer's disease (AD) are closely associated with the impairment of synaptic plasticity. Here, using a mouse model of senescence-accelerated P8 (SAMP8), we reported the role of tripchlorolide (T4), an extract of the natural herb Tripterygium wilfordii Hook F, in improving cognitive deficits and promoting the long-term potentiation (LTP) of hippocampal slices via the N-methyl-D-aspartate receptor (NMDAR)-dependent signaling pathway. Our results demonstrated that chronic administration of T4 at low doses (0.25, 1.0, or 4.0 µg/kg per day, injected intraperitoneally for 75 days) significantly improved learning and memory function in aged SAMP8 mice, as indicated by a chain of behavioral tests including the Y-maze and Morris water maze. Additionally, T4 reversed the impaired LTP in hippocampal CA1 regions of SAMP8 mice in a dose-dependent manner. Moreover, it upregulated the levels of phospho-NMDAR1, postsynaptic density-95 (PSD-95), phospho-calcium-calmodulin dependent kinase II (CaMKII), phospho-CREB and brain derived neurotrophic factor (BDNF) in the hippocampus. This indicates that T4 prevents the impairment of NMDAR-mediated synaptic plasticity-related signal molecules. At optimal doses, T4 did not show significant side-effects on blood counts, blood biochemical measures, or survival of the mice. This novel mechanism in reversing age-related synaptic dysfunction and NMDAR functional deficits suggests that T4 can halt the manifestation of a key early-stage event in AD. With the consideration of SAMP8 mice as a model to develop therapeutic interventions for AD, our findings provide new insight into the clinical application of tripchlorolide in AD treatment.

[Involvement of protein kinase C in NMDAR-dependent long-term potentiation in rat amygdala.].

The mechanism of long-term potentiation (LTP) in basolateral amygdala (BLA) was explored using field potential recording in rat brain slice preparation. Field potentials (field excitatory post-synaptic potentials, fEPSPs) in BLA were evoked with sharpened steel bipolar stimulating electrodes placed in the external capsule (EC). Two theta burst stimulations (TBS, interval=10 min) induced LTP in BLA. TBS-induced synaptic potentiation lasted for more than 30 min after the second TBS. LTP in BLA was input-specific and was blocked by N-methyl-D-aspartate receptor (NMDAR) antagonist 2-amino-5-phosphonovaleric acid (APV). The effect of protein kinase C (PKC) on LTP was then determined using PKC inhibitor chelerythrine chloride. Bath application of chelerythringe chloride had no effect on basic field potentials and paired-pulse ratio (PPR). However, in the presence of chelerythrine chloride, two TBS failed to induce LTP. In contrast, bath application of chelerythrine chloride 10 min after the second TBS did not affect the maintenance of LTP in BLA. These results indicate that LTP is NMDAR-dependent and PKC is involved in the induction and early maintenance of LTP in BLA.