Hypomyelination, hypodontia and craniofacial abnormalities in a Polr3b mouse model of leukodystrophy.

RNA polymerase III (Pol III)-related hypomyelinating leukodystrophy (POLR3-HLD), also known as 4H leukodystrophy, is a severe neurodegenerative disease characterized by the cardinal features of hypomyelination, hypodontia and hypogonadotropic hypogonadism. POLR3-HLD is caused by biallelic pathogenic variants in genes encoding Pol III subunits. While approximately half of all patients carry mutations in POLR3B encoding the RNA polymerase III subunit B, there is no in vivo model of leukodystrophy based on mutation of this Pol III subunit. Here, we determined the impact of POLR3BΔ10 (Δ10) on Pol III in human cells and developed and characterized an inducible/conditional mouse model of leukodystrophy using the orthologous Δ10 mutation in mice. The molecular mechanism of Pol III dysfunction was determined in human cells by affinity purification-mass spectrometry and western blot. Postnatal induction with tamoxifen induced expression of the orthologous Δ10 hypomorph in triple transgenic Pdgfrα-Cre/ERT; R26-Stopfl-EYFP; Polr3bfl mice. CNS and non-CNS features were characterized using a variety of techniques including microCT, ex vivo MRI, immunofluorescence, immunohistochemistry, spectral confocal reflectance microscopy and western blot. Lineage tracing and time series analysis of oligodendrocyte subpopulation dynamics based on co-labelling with lineage-specific and/or proliferation markers were performed. Proteomics suggested that Δ10 causes a Pol III assembly defect, while western blots demonstrated reduced POLR3BΔ10 expression in the cytoplasm and nucleus in human cells. In mice, postnatal Pdgfrα-dependent expression of the orthologous murine mutant protein resulted in recessive phenotypes including severe hypomyelination leading to ataxia, tremor, seizures and limited survival, as well as hypodontia and craniofacial abnormalities. Hypomyelination was confirmed and characterized using classic methods to quantify myelin components such as myelin basic protein and lipids, results which agreed with those produced using modern methods to quantify myelin based on the physical properties of myelin membranes. Lineage tracing uncovered the underlying mechanism for the hypomyelinating phenotype: defective oligodendrocyte precursor proliferation and differentiation resulted in a failure to produce an adequate number of mature oligodendrocytes during postnatal myelinogenesis. In summary, we characterized the Polr3bΔ10 mutation and developed an animal model that recapitulates features of POLR3-HLD caused by POLR3B mutations, shedding light on disease pathogenesis, and opening the door to the development of therapeutic interventions.

Cerebroventricular Injection of Pgk1 Attenuates MPTP-Induced Neuronal Toxicity in Dopaminergic Cells in Zebrafish Brain in a Glycolysis-Independent Manner.

Parkinson's disease (PD) is characterized by the degeneration of dopaminergic neurons. While extracellular Pgk1 (ePgk1) is reported to promote neurite outgrowth, it remains unclear if it can affect the survival of dopaminergic cells. To address this, we employed cerebroventricular microinjection (CVMI) to deliver Pgk1 into the brain of larvae and adult zebrafish treated with methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as a PD-like model. The number of dopamine-producing cells in ventral diencephalon clusters of Pgk1-injected, MPTP-treated embryos increased over that of MPTP-treated embryos. Swimming distances of Pgk1-injected, MPTP-treated larvae and adult zebrafish were much longer compared to MPTP-treated samples. The effect of injected Pgk1 on both dopamine-producing cells and locomotion was time- and dose-dependent. Indeed, injected Pgk1 could be detected, located on dopamine neurons. When the glycolytic mutant Pgk1, Pgk1-T378P, was injected into the brain of MPTP-treated zebrafish groups, the protective ability of dopaminergic neurons did not differ from that of normal Pgk1. Therefore, ePgk1 is functionally independent from intracellular Pgk1 serving as an energy supplier. Furthermore, when Pgk1 was added to the culture medium for culturing dopamine-like SH-SY5Y cells, it could reduce the ROS pathway and apoptosis caused by the neurotoxin MPP+. These results show that ePgk1 benefits the survival of dopamine-producing cells and decreases neurotoxin damage.

Association between estimated glomerular filtration rate and clinical outcomes in ischemic stroke patients with high-grade carotid artery stenosis.

BACKGROUND: Chronic kidney disease has been identified as a risk factor affecting stroke prognosis. High-grade carotid artery stenosis (CAS) is associated with distal hemodynamic compromise. The association between the estimated glomerular filtration rate (eGFR) and ischemic stroke (IS) outcome in patients with high-grade CAS remains unclear. We aimed to investigate the association between eGFR and outcomes of acute IS patients with high-grade CAS. METHODS: From January 1, 2007 to April 30, 2012, we enrolled 372 acute IS patients with high-grade CAS and prospectively observed them for 5 years. The eGFR on admission was assessed using the Modification of Diet in Renal Disease Study equation. Demographic features, vascular risk factors, comorbidities, and outcomes were compared between different eGFR levels. RESULTS: Among 372 individuals, 76 (20.4%) had an eGFR < 45, 65 (17.5%) had an eGFR between 45 and 59, and 231 (62.1%) had an eGFR ≥60 mL/min/1.73 m2. Compared to other groups, in the eGFR < 45 mL/min/1.73 m2 group, the prevalence rates of hypertension, diabetes mellitus, coronary artery disease, congestive heart failure, valvular heart disease, and gout were significantly higher (P = 0.013, P = 0.030, P = 0.001, P < 0.001, P = 0.043, and P < 0.001, respectively). Patients with eGFR < 45 mL/min/1.73 m2 demonstrated lower hemoglobin and total cholesterol levels compared with other groups (P < 0.001 and P = 0.048). The blood potassium and uric acid levels were significantly higher in patients with eGFR < 45 mL/min/1.73 m2 (P < 0.001 and P < 0.001). The multivariate Cox proportional hazards model indicated that eGFR < 45 mL/min/1.73 m2 was a significant risk factor for 5-year all-cause mortality in IS patients with high-grade CAS after adjusting for these variables (hazard ratio = 2.05; 95% CI = 1.31-3.21; P = 0.002). CONCLUSIONS: eGFR < 45 mL/min/1.73 m2 was associated with an increased risk of 5-year all-cause mortality in acute IS patients with high-grade CAS. Whether aggressive treatment of chronic kidney disease in IS patients with high-grade CAS can improve stroke outcomes should be confirmed in future studies.

Association between Pre-Existing Coronary Artery Disease and 5-Year Mortality in Stroke Patients with High-Grade Carotid Artery Stenosis.

BACKGROUND: The coincidence of coronary artery disease (CAD) and carotid artery stenosis (CAS) was observed. However, the association between pre-existing CAD and ischemic stroke (IS) outcome in patients with high-grade CAS remains unclear. We aimed to investigate the association between pre-existing CAD and outcomes of acute IS patients with high-grade CAS. METHODS: From January 1, 2007, to April 30, 2012, we enrolled 372 acute IS patients with high-grade CAS and prospectively observed them for 5 years. Demographic features, vascular risk factors, comorbidities, and outcomes were compared between patients with and without pre-existing CAD. RESULTS: Among 372 individuals, 75 (20.2%) patients had pre-existing CAD and 297 (79.8%) patients did not have pre-existing CAD. The prevalence rates of hypertension, congestive heart failure, chronic kidney disease, and gout in patients with pre-existing CAD were significantly higher than in those without pre-existing CAD (p = 0.017, p < 0.001, p = 0.002, and p < 0.001, respectively). The multivariate Cox proportional hazards model revealed that pre-existing CAD was a significant risk factor for a 5-year all-cause mortality in acute IS patients with high-grade CAS (hazard ratio = 2.26; 95% confidence interval = 1.35-3.79; p = 0.002). CONCLUSION: Pre-existing CAD was associated with an increased risk of 5-year mortality in acute IS patients with high-grade CAS. Intensive treatment for the pre-existing CAD may reduce long-term mortality in acute IS patients with high-grade CAS.

Cytokine changes during treatment of anti-Caspr2 encephalitis: a case report.

BACKGROUND: Cytokines are effective molecules of immune reactions. They work in inflammatory sites as well as circulate in the blood. Cytokines in the cerebrospinal fluid have been suggested to be markers of autoimmune encephalitis and reflect disease progression. However, studies on blood cytokines in autoimmune encephalitis are scarce. We report a case presenting with serial changes in blood cytokine levels in a male patient with anti-contactin-associated protein 2 (Caspr2) encephalitis. CASE PRESENTATION: A 61-year-old man without systemic disease presented with ataxia and speech disturbance 1 week. After admission, he further developed visual hallucinations, psychosis, and consciousness deterioration. Brain magnetic resonance imaging and infection and tumor surveillances were negative. 18F-fluorodeoxyglucose positron emission tomography of brain revealed frontal and occipital hypometabolism and anterior cingulate gyrus and mesial temporal hypermetabolism. Autoimmune studies confirmed Caspr2 antibodies in his blood. After receiving a diagnosis of anti-Caspr2 encephalitis, the patient received steroids, plasmapheresis, and zonisamide. He recovered well and was totally independent 6 months after disease onset. A cytokine profiler array kit was used to investigate neuroimmune mechanisms during the disease course. Several cytokines showed significant changes in plasma levels, such as B cell activating factor for B cell proliferation; thymus and activation-regulated chemokine for T cell chemoattraction; soluble CD40 ligand for Th2 cell mediation; C5/C5a for complement activation; brain-derived neurotrophic factor for neuronal survival response; and dipeptidyl peptidase 4, retinol binding protein, dickkopf-related protein, and epidermal growth factor for response to environmental provocation. The concentration of cytokines was verified using Luminex multiplexing assay. CONCLUSIONS: Due to their easy accessibility, blood cytokines are potential biomarkers of autoimmune encephalitis. Based on the investigating platform of this single case study, future larger scale studies are warranted.

Cucurbitane-Type Triterpenoids from the Vines of Momordica charantia and Their Anti-inflammatory Activities.

Seven new cucurbitane-type triterpenoids, kuguaovins A-G (1-7), and five known ones were isolated from the rattans of wild Momordica charantia. Their structures were established by spectroscopic data analyses, including 1D and 2D NMR, IR, and MS techniques. The absolute configurations of the cucurbitanes were determined from NOESY data and partially by X-ray crystallographic analysis. In pharmacological studies, compounds 1-7 and 9-12 exhibited weak anti-inflammatory effects (IC50 = 15-35 µM), based on an anti-NO production assay.

Adjuvant therapy by high-speed burr may cause intraoperative bone tumor seeding: an animal study.

BACKGROUND: Bone tumors are often treated with intralesional curettage. High-speed burring, an adjuvant therapy, was performed to maximize the tumor cell killing; however, tumor recurrence might still occur, which may be caused by residual tumor or local tumor spread during surgery. METHODS: A porcine cadaver (femur) was utilized to determine whether the use of a high-speed burr causes bone cement spray. To mimic residual tumor after curettage, luminescent cement was smeared on two locations of the bone cavity, the wall and the bottom. The cavity in the femoral bone was then placed in the middle of a sheet of drawing paper featuring 10 cm, 20 cm, and 30 cm concentric circles. The luminescent cement was then burred totally with a high-speed burr. RESULTS: The intensity of the area in the wall in circle I was 72.6% ± 5.8%; within circle II, it was 22.1% ± 4.2%; and within circle III, it was 5.4% ± 1.5%. The intensity of the area within the bottom of the femoral bone within circle I was 66.5% ± 6.1%, within circle II was 28.1 ± 4.8%, and within circle III, it was 5.4% ± 1.4%. The amount of luminescent cement seeding decreased with distance, but there was no difference while burring at different locations of the bone cavity. Under the handpiece cover, a greater amount of cement spray was retained in circle I during burring of the cement in the bottom of the cavity and less was sprayed out in circle III. CONCLUSIONS: High-speed burring may cause explosive bone cement spray, which could extend to 20 cm. The intensities of spray did not decrease, even when the handpiece cover was used. The wide range of bone cement spray caused by high-speed burr was inspected in this pilot study, which may lead to tumor seeding. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Concomitant Guillain-Barré Syndrome and Acute Transverse Myelitis in an Older Adult-A Case Report.

PURPOSE: Guillain-Barré syndrome concomitant with spinal cord involvement, which is defined as Guillain-Barré syndrome and acute transverse myelitis overlap syndrome, is rarely seen in the elders. Here we present a 68-year-old female patient who developed Guillain-Barré syndrome, as well as acute transverse myelitis at the same episode. CASE REPORT: This patient developed acute weakness of lower limbs, which then rapidly became tetraplegia and hyporeflexia within 5 days. She also had impaired pinprick and vibration sensations below T4, as well as urinary and defecation incontinence. The nerve conduction studies revealed a motorsensory axonal neuropathy. Cerebrospinal fluid analysis showed albuminocytological dissociation and elevated IgG index. The spinal magnetic resonance imaging study revealed heterogeneously contrastenhanced, long-segmental intramedullary lesion from C2 to T3. Other laboratory findings, including blood anti-aquaporin 4 antibody, were not remarkable. The patient's tetraplegia was gradually improved by plasmapheresis and methylprednisolone pulse therapy. CONCLUSION: Although Guillain-Barré syndrome and acute transverse myelitis overlap syndrome is occasionally seen in young adults, it could still occur in the elderly patients. Plasmapheresis and steroid pulse therapy could be beneficial to improve functional outcome of patients with this immunemediated neurological disease.

Association Between Total Cholesterol and 5 year Mortality in Patients with Carotid Artery Stenosis and Poststroke Functional Dependence.

BACKGROUND: Aggressive lipid-lowering treatment reduces the risk of cardiovascular events, but remains controversial in stroke patients. We investigate the influence of total cholesterol level on 5-year outcomes of ischemic stroke patients with high-grade internal carotid artery (ICA) stenosis and poststroke functional dependence. METHODS: One-hundred and ninety-six acute ischemic stroke patients with high-grade ICA stenosis and modified Rankin Scale score ≥ 3 upon discharge were enrolled and prospectively observed for 5 years. Patients were divided into 2 groups according to total cholesterol level at admission: ≥200 mg/dL or <200 mg/dL. Demographic features, vascular risk factors, co-morbidities, and outcomes were compared between the 2 groups. RESULTS: 117 (59.7%) patients had higher and 79 (40.3%) patients had lower total cholesterol levels. The prevalence of older age and atrial fibrillation was significantly higher in patients with lower total cholesterol; the prevalence of diabetes mellitus was higher in patients with higher total cholesterol. After adjusting for the established clinical predictors of adverse outcomes, the multivariate Cox regression revealed that lower total cholesterol level is a significant predictor of 5-year mortality (HR (hazard ratio) = 1.88, 95% CI (confidence interval) = 1.09-3.23, P = .023). CONCLUSIONS: Lower total cholesterol level is associated with increased risk of 5-year mortality in ischemic stroke patients with high-grade ICA stenosis and post-stroke functional dependence. Aggressive treatment of hyperlipidemia should be carefully considered in these patients although it could reduce the risk of atherosclerotic cardiovascular diseases and stroke recurrence in some stroke patients.

Chondroitin Sulfate Proteoglycans Negatively Modulate Spinal Cord Neural Precursor Cells by Signaling Through LAR and RPTPσ and Modulation of the Rho/ROCK Pathway.

Multipotent adult neural precursor cells (NPCs) have tremendous intrinsic potential to repair the damaged spinal cord. However, evidence shows that the regenerative capabilities of endogenous and transplanted NPCs are limited in the microenvironment of spinal cord injury (SCI). We previously demonstrated that injury-induced upregulation of matrix chondroitin sulfate proteoglycans (CSPGs) restricts the survival, migration, integration, and differentiation of NPCs following SCI. CSPGs are long-lasting components of the astroglial scar that are formed around the lesion. Our recent in vivo studies demonstrated that removing CSPGs from the SCI environment enhances the potential of transplanted and endogenous adult NPCs for spinal cord repair; however, the mechanisms by which CSPGs regulate NPCs remain unclear. In this study, using in vitro models recapitulating the extracellular matrix of SCI, we investigated the direct role of CSPGs in modulating the properties of adult spinal cord NPCs. We show that CSPGs significantly decrease NPCs growth, attachment, survival, proliferation, and oligodendrocytes differentiation. Moreover, using genetic models, we show that CSPGs regulate NPCs by signaling on receptor protein tyrosine phosphate sigma (RPTPσ) and leukocyte common antigen-related phosphatase (LAR). Intracellularly, CSPGs inhibitory effects are mediated through Rho/ROCK pathway and inhibition of Akt and Erk1/2 phosphorylation. Downregulation of RPTPσ and LAR and blockade of ROCK in NPCs attenuates the inhibitory effects of CSPGS. Our work provide novel evidence uncovering how upregulation of CSPGs challenges the response of NPCs in their post-SCI niche and identifies new therapeutic targets for enhancing NPC-based therapies for SCI repair.

Association between Atrial Fibrillation and Three-Year Mortality in Nondiabetic Patients with Acute First-Ever Ischemic Stroke.

BACKGROUND: Diabetes mellitus (DM) is a risk factor for atrial fibrillation (AF) and is known to be an important risk factor for death from stroke. The influence of AF on long-term outcomes in patients with ischemic stroke remains controversial. To clarify the exact influence of AF on stroke outcome and exclude the effect from DM, we investigated the influence of AF on the 3-year outcomes of nondiabetic patients with acute first-ever ischemic stroke. METHODS: Five-hundred seventy-four nondiabetic patients with acute first-ever ischemic stroke were enrolled and had been followed for 3 years. Patients were divided into 2 groups according to whether AF was diagnosed or not. Clinical presentations, risk factors for stroke, laboratory data, comorbidities, and outcomes were recorded. RESULTS: A total of 107 patients (18.6%) had AF. The age was significantly older in patients with AF. Total anterior circulation syndrome occurred more frequently among patients with AF (P < .001). The mean length of stay in the acute ward was significantly higher in patients with AF (P < .001). Furthermore, dependent functional status following discharge was higher in patients with AF (P < .001). Multivariate Cox regression revealed that AF is a significant predictor of 3-year all-cause mortality (hazard ratio = 1.98, 95% confidence interval = 1.07-3.67, P = .022). CONCLUSIONS: AF is associated with increased risk of 3-year mortality in nondiabetic patients with acute first-ever ischemic stroke. Careful cardiac evaluation and treatment are essential in patients with AF and stroke.

NGAL can alternately mediate sunitinib resistance in renal cell carcinoma.

PURPOSE: Serum NGAL is highly expressed in patients with advanced renal cancer treated with sunitinib. We investigated the role of NGAL in sunitinib resistance in renal cell carcinoma to identify potential tactics to overcome it. MATERIALS AND METHODS: NGAL expression was correlated with sunitinib sensitivity. Vascular endothelial growth factor related upstream Ras, Erk1/2 and STAT1 phosphorylation activity in Caki-1 and NGAL transfected Caki-1 cells after sunitinib treatment was analyzed using Western blot. NGAL and vascular endothelial growth factor-A interaction with sunitinib therapeutic efficacy was monitored in renal cell carcinoma tumor xenografted mice by tumor growth inhibition, serum NGAL and vascular endothelial growth factor-a levels, and microscopic examination of tumor microvascular density. RESULTS: Sunitinib cytotoxicity in various renal cell carcinoma cell lines was reversibly related to NGAL expression. Sunitinib showed the lowest 50% inhibitory concentration (5.53 µM) in Caki-1 cells, which had the lowest NGAL expression of these renal cell carcinoma cell lines. After sunitinib treatment adding NGAL inhibited Ras and Erk1/2 phosphorylation but activated STAT1α phosphorylation in Caki-1 cells and Caki-1 cells transfected with NGAL. In a xenograft mouse model sunitinib significantly inhibited tumor growth in Caki-1 mice. NGAL transfected Caki-1 mice had higher serum NGAL and lower vascular endothelial growth factor-A than Caki-1 mice. Microvascular density was decreased in Caki-1 mice with sunitinib treatment. CONCLUSIONS: NGAL in tumor cells may show crosstalk with vascular endothelial growth factor-a and alternative activation in stimulating tumor growth during sunitinib treatment. It may become a therapeutic target to reverse sunitinib resistance in renal cell carcinoma.

Identification of PTPsigma as an autophagic phosphatase.

Macroautophagy is a dynamic process whereby portions of the cytosol are encapsulated in double-membrane vesicles and delivered to the lysosome for degradation. Phosphatidylinositol-3-phosphate (PtdIns3P) is concentrated on autophagic vesicles and recruits effector proteins that are crucial for this process. The production of PtdIns3P by the class III phosphatidylinositol 3-kinase Vps34, has been well established; however, protein phosphatases that antagonize this early step in autophagy remain to be identified. To identify such enzymes, we screened human phosphatase genes by RNA interference and found that loss of PTPσ, a dual-domain protein tyrosine phosphatase (PTP), increases levels of cellular PtdIns3P. The abundant PtdIns3P-positive vesicles conferred by loss of PTPσ strikingly phenocopied those observed in cells starved of amino acids. Accordingly, we discovered that loss of PTPσ hyperactivates both constitutive and induced autophagy. Finally, we found that PTPσ localizes to PtdIns3P-positive membranes in cells, and this vesicular localization is enhanced during autophagy. We therefore describe a novel role for PTPσ and provide insight into the regulation of autophagy. Mechanistic knowledge of this process is crucial for understanding and targeting therapies for several human diseases, including cancer and Alzheimer's disease, in which abnormal autophagy might be pathological.

Elevated plasma neurofilament light chain in immune-mediated neurological disorders (IMND) detected by immunomagnetic reduction (IMR).

BACKGROUND: In cases of immune-mediated neurological disorders (IMND), different syndromes are associated with antibodies against neuronal surface antigens, intra-neuronal antigens, astrocytic aquaporin, and gangliosides. These autoantibodies can be pathogenic or connected to neuroinflammation and resulting neuronal injuries. This study aims to identify a blood biomarker that can detect neuronal damage in individuals with IMND. To this end, we use immunomagnetic reduction (IMR) nanobead technology to measure plasma neurofilament light chain (NfL). METHODS: The patients with IMND were enrolled in the Chang Gung Memorial Hospital at Keelung from 2018 to 2023. Seronegative patients were excluded based on the results of antibody tests. The healthy controls (HC) were community-dwelling adults from the Northeastern Taiwan Community Medicine Research Cohort (NTCMRC) conducted by the Community Medicine Research Center of the Keelung CGMH from 2020 to 2022. IMR technique detects magnetic susceptibility via measuring magnetic signal reduction caused by antigen-antibody immunocomplex formation on magnetic nanobeads. The plasma level of NfL was determined by the magnetic susceptibility changes in IMR. RESULTS: The study enrolled 57 IMND patients from the hospital and 73 HC participants from the communities. The plasma NfL was significantly higher in the IMND than in the HC (11.022 ± 2.637 vs. 9.664 ± 2.610 pg/mL, p = 0.004), regardless of age effects on plasma NfL in an analysis of covariance (ANCOVA) (F = 0.720, p = 0.950). In the receiver of operation curve analysis, the area under curve for plasma NfL to discriminate IMND and HC was 0.664 (95% CI = 0.549 to 0.739, p = 0.005). The subgroup analysis of plasma NfL in the IMND patients showed no difference between peripheral immune-mediated neuropathy (IMN) and central immune-mediated encephalomyelitis (IMEM) (11.331 ± 2.895 vs. 10.627 ± 2.260 pg/mL, p = 0.322), nor between tumor and non-tumor IMND (10.784 ± 3.446 vs. 11.093 ± 2.391 pg/mL, p = 0.714). Additionally, the antibody class of ganglioside antibodies in IMN did not have an impact on plasma NfL level (p = 0.857). CONCLUSION: Plasma NfL measurement is a reliable indicator of axonal injuries in patients with IMND. It is equally effective in detecting nerve injuries in inflammatory peripheral neuropathies and central neuroinflammation. The IMR nanobead technology offers a feasible method of detecting plasma NfL, which helps identify axonal injuries in IMND.

Receptor protein tyrosine phosphatase sigma regulates synapse structure, function and plasticity.

The mechanisms that regulate synapse formation and maintenance are incompletely understood. In particular, relatively few inhibitors of synapse formation have been identified. Receptor protein tyrosine phosphatase σ (RPTPσ), a transmembrane tyrosine phosphatase, is widely expressed by neurons in developing and mature mammalian brain, and functions as a receptor for chondroitin sulfate proteoglycans that inhibits axon regeneration following injury. In this study, we address RPTPσ function in the mature brain. We demonstrate increased axon collateral branching in the hippocampus of RPTPσ null mice during normal aging or following chemically induced seizure, indicating that RPTPσ maintains neural circuitry by inhibiting axonal branching. Previous studies demonstrated a role for pre-synaptic RPTPσ promoting synaptic differentiation during development; however, subcellular fractionation revealed enrichment of RPTPσ in post-synaptic densities. We report that neurons lacking RPTPσ have an increased density of pre-synaptic varicosities in vitro and increased dendritic spine density and length in vivo. RPTPσ knockouts exhibit an increased frequency of miniature excitatory post-synaptic currents, and greater paired-pulse facilitation, consistent with increased synapse density but reduced synaptic efficiency. Furthermore, RPTPσ nulls exhibit reduced long-term potentiation and enhanced novel object recognition memory. We conclude that RPTPσ limits synapse number and regulates synapse structure and function in the mature CNS.

Association of hyponatremia in acute stroke stage with three-year mortality in patients with first-ever ischemic stroke.

BACKGROUND: Hyponatremia is the most common electrolyte disorder in hospitalized patients, and is frequently a marker of a significant underlying disease. The prognostic value of hyponatremia in patients with acute first-ever ischemic stroke is not known. We aimed to analyze whether hyponatremia in the acute stroke stage contributed to the risk of mortality or recurrent stroke in these patients. METHODS: We studied 925 patients presenting with acute first-ever ischemic stroke between 2002 and 2004. Sodium levels were obtained on arrival at the emergency room within 3 days of acute stroke onset. Hyponatremia was defined as a serum sodium concentration of 134 mmol/l or less. Clinical presentation, stroke risk factors, associated medical disease, and outcome were recorded. All patients were followed for 3 years for survival analysis. A multivariate Cox proportional hazards model was used to identify risk factors for 3-year mortality in these patients. We also constructed Kaplan-Meier survival curves, and compared groups with hyponatremia and normonatremia by means of log rank tests for significant differences. RESULTS: Among the patients with acute first-ever ischemic stroke, 107 (11.6%) were hyponatremic. Among stroke risk factors, the prevalence of diabetes mellitus was significantly higher among hyponatremic patients (p < 0.001). Prevalence of chronic renal insufficiency was also higher in the hyponatremic group (p = 0.002). Clinical presentations, such as the length of acute ward stay, initial impaired consciousness, and clinical course in acute stroke were similar among normo- and hyponatremic patients. Among the complications, pneumonia and urinary tract infection were significantly higher in hyponatremic than in normonatremic patients. After multivariate logistic regression analysis, diabetes mellitus and chronic renal insufficiency were associated with hyponatremia in these patients. Kaplan-Meier analysis indicated that the survival rate was significantly lower in hyponatremic patients than in normonatremic patients (log rank test; p value <0.001). After multivariate Cox proportional hazards model analysis, hyponatremia was a significant predictor of 3-year mortality in these patients after adjustment for related variables (p value = 0.003, hazard ratio = 2.23, 95% confidence interval: 1.30-3.82). CONCLUSION: Hyponatremia in the acute stroke stage is a predictor of 3-year mortality in patients with acute first-ever ischemic stroke that is independent of other clinical predictors of adverse outcome.

Dock/Nck facilitates PTP61F/PTP1B regulation of insulin signalling.

PTP1B (protein tyrosine phosphatase 1B) is a negative regulator of IR (insulin receptor) activation and glucose homoeostasis, but the precise molecular mechanisms governing PTP1B substrate selectivity and the regulation of insulin signalling remain unclear. In the present study we have taken advantage of Drosophila as a model organism to establish the role of the SH3 (Src homology 3)/SH2 adaptor protein Dock (Dreadlocks) and its mammalian counterpart Nck in IR regulation by PTPs. We demonstrate that the PTP1B orthologue PTP61F dephosphorylates the Drosophila IR in S2 cells in vitro and attenuates IR-induced eye overgrowth in vivo. Our studies indicate that Dock forms a stable complex with PTP61F and that Dock/PTP61F associate with the IR in response to insulin. We report that Dock is required for effective IR dephosphorylation and inactivation by PTP61F in vitro and in vivo. Furthermore, we demonstrate that Nck interacts with PTP1B and that the Nck/PTP1B complex inducibly associates with the IR for the attenuation of IR activation in mammalian cells. Our studies reveal for the first time that the adaptor protein Dock/Nck attenuates insulin signalling by recruiting PTP61F/PTP1B to its substrate, the IR.

The Study of 3D Printing-Assisted Electrospinning Technology in Producing Tissue Regeneration Polymer-Fibroin Scaffold for Ureter Repair.

OBJECTIVE: Long segment ureteral lesion with obstruction is a clinically difficult issue for recovering and maintaining organ or tissue function. Regeneration medicine using various biomaterials as a scaffold in supporting tissue regrowth is emerging. We developed this customized scaffold using electrospinning and 3-dimensional assistance and expected that it may provide an alternative biomaterial for ureter defect repair. MATERIAL AND METHODS: Our study synthesized polycaprolactone and silk fibroin combination as biomaterial scaffolds. The differences in physicochemical properties and biocompatibility of polycaprolactone-silk fibroin bio-scaffolds prepared by electrospinning alone and 3-dimensional printing combined with electrospinning in proper ratios were compared and characterized. SV-HUC-1 uroepithelial cells cultured in polycaprolactone-silk fibroin (4 : 6) scaffolds were observed under a scanning electron microscope and using calcein-acetomethoxy and propidium iodide stain. The ex vivo resected healthy human ureteral segment tissue was anastomosed with the polycaprolactone-silk fibroin scaffolds and cultured in an ex vivo bath for 2 weeks. The cellular growth on the polycaprolactone-silk fibroin scaffold was observed microscopically. In the New Zealand white rabbit model, we performed a 1/5 ratio (2 cm out of 10 cm) defect replacement of the unilateral ureter. After 7 weeks, the rabbits were sacrificed and the implanted ureter scaffolds were resected for tissue sectioning and the cellular growth was observed by hematoxylin and eosin and Masson staining. RESULTS: When the proportion of silk fibroin was increased and the 3-dimensional electrospinning method was used, both the size and diameter of nanofiber holes were increased in the polycaprolactone-silk fibroin scaffold. Scanning electron microscope and fluorescent stain revealed that cultured 3T3 and SV-HUC-1 uroepithelial cells could electively penetrate inside the polycaprolactone-silk fibroin (4 : 6) nanofibrous scaffolds in 3 days. The polycaprolactone-silk fibroin scaffold anastomosis in an ex vivo bath showed cellular growth stably along the scaffold for 2 weeks, and most of the cells grow along with the outboard of the scaffold in layers. In an animal model, different layered cells can be observed to grow along with the outboard of the scaffold with mucosa, submucosa, muscular layer, and the serosa layer order after 7 weeks. Mucosa and muscular layer growth along the scaffold inner wall were seen simultaneously. CONCLUSION: 3-dimensional electrospinning synthesized 4 : 6 polycaprolactone-silk fibroin nanofiber scaffolds that are feasible for tissue growth and achieve the purpose of ureteral reconstruction in animal experiments. This new form of 3-dimensional electrospinning constructed polycaprolactone-silk fibroin nanofiber scaffold may be considered as a clinical urinary tract tissue reconstruction alternative in the future.

Cucurbitane-type triterpenoids from the vines of Momordica charantia and their anti-inflammatory, cytotoxic, and antidiabetic activity.

Phytochemical investigation of the ethanol extract from wild Momordica charantia vines has resulted in isolation of seven cucurbitane-type triterpenoids, including six undescribed compounds, kuguaovins H‒M, and the known compound, momordicoside K. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, and MS experiments. The chemical structure of momordicoside K was determined for the first time by X-ray crystallographic analysis and its absolute configuration assigned. The cytotoxicity against four human tumor cell lines and anti-inflammatory activities on LPS-stimulated RAW264.7 macrophages were evaluated. Of the isolates, kaguaovin L exhibited potential cytotoxicity against MCF-7, HEp-2, Hep-G2, and WiDr cancer cell lines and showed moderate anti-NO production activity. In addition, kuguaovins H and J also showed the stimulatory effect of GLP-1 secretion on the murine intestinal secretin tumor cell line (STC-1).

Clinical characteristics of adult tetanus in a Taiwan medical center.

BACKGROUND/PURPOSE: Despite effective vaccine programs, tetanus is occasionally observed in adults. We reviewed clinical presentation data for adult patients with tetanus in the post-vaccine era in Taiwan. METHODS: We retrospectively reviewed the medical records of all adult patients (age >18 years) discharged from Chang-Gung Memorial Hospital at Lin-Ko (CGMHLK) after treatment for tetanus between January 1996 and July 2005. Data regarding demographic characteristics, clinical manifestation, treatment, and outcome were collected. To assess the features for different age groups, patients were divided into those aged ≥65 years and those aged <65 years. To identify risk factors for respiratory failure, the patients were classified as those with and without respiratory failure. RESULTS: Twenty-three patients with tetanus, 11 (48%) women and 12 (52%) men, were included in the study. The average age was 57 ± 18 years (range 18-84 years). Eighteen (78%) patients had a history of acute injury. The average incubation period was 8 ± 5 days. The most common clinical presentation at onset was trismus (78%). Thirteen (57%) patients developed respiratory failure and underwent endotracheal intubation. The most common complication was pneumonia (30%). All the patients survived and recovered. Age ≥65 years was significantly associated with trismus, dysphagia, dysarthria, and pneumonia. Generalized tetanus subtype and pneumonia were significant risk factors for respiratory failure. CONCLUSION: This study revealed several characteristics of adult tetanus cases in the post-vaccine era in Taiwan. Further serological studies and improved tetanus vaccinations may be needed to ensure better protection, especially for high-risk populations. The exceptionally good prognosis for our patients confirms that appropriate treatment, including wound care, early diagnosis, proper medication, and prevention of complications, is essential in managing this traditional curable disease.