Efficacy of MEM 1003, a novel calcium channel blocker, in delay and trace eyeblink conditioning in older rabbits

Eyeblink conditioning is a relatively simple form of associative learning that shows neurobiological and behavioral parallels across several species, including humans. Aged subjects acquire eyeblink conditioning more slowly than young ones. In addition, eyeblink conditioning effectively discriminates patients with Alzheimer's disease from healthy older adults. The present study evaluated the effect of a novel L-type Ca2+ channel antagonist, MEM 1003, on delay and trace eyeblink conditioning in older (mean 33.4 months old) female New Zealand white rabbits. In the delay conditioning paradigm, an 850 ms tone conditioning stimulus (CS) was followed 750 ms after its onset by a 100 ms corneal air puff. Several trace conditioning paradigms were evaluated, with a silent period of 300, 400 or 500 ms between the end of the tone CS and the delivery of the air puff. Learning was more difficult in the longer trace paradigms than in the delay paradigm. MEM 1003, at a dose of 2.0 mg/kg, s.c., given daily 30 min prior to training on each of the 15 training days, enhanced learning compared to vehicle injections in both delay and trace paradigms. However, higher or lower doses were ineffective. These results support previous work demonstrating that modulation of Ca2+ channel activity can reduce age-related cognitive impairments.     

Differential effects of ceramide species on exocytosis in rat PC12 cells

Increases in several ceramide species have been shown by non-targeted lipid profiling (lipidomics) of the rat hippocampus after kainate lesions (Guan et al. FASEB J 20:1152–1161, 2006). This study was carried out to examine possible effects of ceramide species on exocytosis. Significant increase in membrane capacitance in voltage-clamped rat pheochromocytoma (PC12) cells, an indication of exocytosis, was detected immediately after external application of C2, C6, and C18 ceramide. In contrast, no increase in capacitance was found after addition of C16 and C20 ceramide, or DMSO vehicle. The effect of ceramide on exocytosis was dependent on the integrity of lipid rafts. Treatment of cells with the cholesterol binding agent/disruptor of lipid rafts, methyl β cyclodextrin, prior to addition of C18 ceramide suppressed the increase in capacitance induced by this lipid species. The ability of C2, C6 and C18 ceramide to trigger exocytosis was confirmed using total internal reflection fluorescence microscopy (TIRFM) experiments. External application of these species caused an exponential decrease in the number of subplasmalemmal neuropeptide Y (NPY)-enhanced green fluorescence protein (EGFP) labeled vesicles, indicating exocytosis. Interestingly, C18 is also the ceramide species that showed the greatest increase in the rat hippocampus after kainate excitotoxicity. It is postulated that C18 ceramide might facilitate exocytosis of glutamate from damaged neurons, thus propagating neuronal injury.     

Demonstration of In Vitro Host-Guest Complex Formation and Safety of para-Sulfonatocalix[8]arene as a Delivery Vehicle for Two Antibiotic Drugs

The macrocycle para-sulfonatocalix[8]arene, sCX[8], was examined with 2 antibiotic drugs, ciprofloxacin (CIP) and isoniazid. The drugs were shown to form complexes with sCX[8] using proton nuclear magnetic resonance, thermogravimetric analysis, fluorescence spectroscopy, and molecular modeling. Both drugs form 1:1 hydrated (H₂O: 13%-14% w/w) host-guest complexes, with sCX[8] binding around the pyridine ring of isoniazid, and around the piperazine and cyclopropane rings of CIP. From proton nuclear magnetic resonance, the binding constant of isoniazid to sCX[8] was 6.8 (±0.3) × 10³ M^?1. Addition of 2 equivalents of sCX[8] to CIP resulted in a 58% decrease in fluorescence, and time-resolved fluorescence anisotropy of CIP doubles with sCX[8]. Each drug binds into the cavity of the macrocycle, with binding stabilized via combinations of hydrogen bonding, electrostatic interactions, π-π stacking, and hydrophobic effects. The safety of sCX[8] was examined in vitro with human embryonic kidney 293 cells. The IC₅₀ of sCX[8] was 559 μM, which is a minimum of 5-fold higher than the concentration that would be used in the clinic. The in vitro effect of sCX[8] on the action of CIP was examined on a panel of bacterial lines. The results showed that sCX[8] has no inherent antibiotic activity and had no negative effect on the action of CIP.     

Facial deformation following treatment for pediatric head and neck rhabdomyosarcoma; the difference between treatment modalities. Results of a trans-Atlantic,multicenter cross-sectional cohort study

Background

The four different local therapy strategies used for head and neck rhabdomyosarcoma (HNRMS) include proton therapy (PT), photon therapy (RT), surgery with radiotherapy (Paris-method), and surgery with brachytherapy (AMORE). Local control and survival is comparable; however, the impact of these different treatments on facial deformation is still poorly understood. This study aims to quantify facial deformation and investigates the differences in facial deformation between treatment modalities.

Methods

Across four European and North American institutions, HNRMS survivors treated between 1990 and 2017, more than 2 years post treatment, had a 3D photograph taken. Using dense surface modeling, we computed facial signatures for each survivor to show facial deformation relative to 35 age–sex–ethnicity-matched controls. Additionally, we computed individual facial asymmetry.

Findings

A total of 173 HNRMS survivors were included, survivors showed significantly reduced facial growth (p < .001) compared to healthy controls. Partitioned by tumor site, there was reduced facial growth in survivors with nonparameningeal primaries (p = .002), and parameningeal primaries (p ≤.001), but not for orbital primaries (p = .080) All patients were significantly more asymmetric than healthy controls, independent of treatment modality (p ≤ .001). There was significantly more facial deformation in orbital patients when comparing RT to AMORE (p = .046). In survivors with a parameningeal tumor, there was significantly less facial deformation in PT when compared to RT (p = .009) and Paris-method (p = .007).

Interpretation

When selecting optimal treatment, musculoskeletal facial outcomes are an expected difference between treatment options. These anticipated differences are currently based on clinicians’ bias, expertise, and experience. These data supplement clinician judgment with an objective analysis highlighting the impact of patient age and tumor site between existing treatment options.     

In vivo evaluation of biomechanical anterior cervical plate failure

Anterior cervical plate (ACP) failure is rarely addressed in the literature. In this retrospective, observational, longitudinal, cohort study, the objectives were to (1) identify incidences of in vivo biomechanical failure in commercially available, US Food and Drug Administration-approved ACP systems, (2) describe modes of failure, (3) suggest structural explanations for system failure, and (4) discuss complications and treatment of patients with failed ACP systems. Investigators retrospectively identified patients who underwent anterior cervical procedures followed by use of ACP as a fusion adjunct and showed evidence of ACP failure on plain radiographs. Components of the ACP system that led to failure were identified and examined. A total of 240 patients received ACP supplementation of anterior cervical fusion constructs during the 9.5-y study period. Evidence of ACP failure was noted in 7 patients (3.3%), and an eighth patient was referred for evaluation after ACP failure. Screw-plate interface failure occurred in all 8 cases. The biomechanical method by which the bone screw head was secured into the vertebral body, or against the ACP, the use of hybrid systems, the surgical technique selected, and host factors were used to determine the rate of failure. Concern for esophageal or other tissue injury often necessitated ACP removal. Screw-plate interface failure, which was found to be the most common mode of biomechanical ACP failure, may occur in hybrid constructs and in systems that do not create a rigid interface between the screw head and the ACP. Surgical technique and patient host factors may also influence the rate of biomechanical construct failure.     

Location of Lymph Node Involvement in Patients with Esophageal Adenocarcinoma Predicts Survival

Background

The location of positive lymph nodes has been abandoned in the seventh classification of the TNM staging system for esophageal adenocarcinoma. The present study evaluates whether distribution of involved nodes relative to the diaphragm in addition to TNM 7 further refines prediction.

Methods

Pathology reports of patients who underwent esophagectomy between 2000 and 2008 for adenocarcinoma of the esophagus were reviewed and staging was performed according to the seventh UICC-AJCC staging system. In addition, lymph node involvement of nodal stations above and below the diaphragm was investigated by endoscopic ultrasonography (EUS) in a separate cohort of patients who were scheduled for esophagectomy between 2008 and 2009 at two institutions. Survival was calculated by the Kaplan–Meier method, and multivariate analysis was performed with a Cox regression model.

Results

Some 327 patients who had undergone esophagectomy for cancer were included. Multivariate analysis revealed that patients with from three to six involved lymph nodes in the resection specimen on both sides of the diaphragm had a twofold higher chance of dying compared to patients with the same number of involved lymph nodes on one side of the diaphragm. EUS assessment of lymph node metastases relative to the diaphragm in 102 patients showed that nodal involvement on both sides of the diaphragm was associated with worse survival than when nodes on one side or no nodes are involved [HR (95 % CI) 2.38 (1.15–4.90)].

Conclusions

A combined staging system that incorporates distribution of lymph nodes relative to the diaphragm refines prognostication after esophagectomy as assessed in the resected specimen and pretreatment as assessed by EUS. This improved staging has the potential to have a great impact on clinical decision making as to whether to embark upon potentially curative or palliative treatments.     

23Na-magnetic resonance imaging of the human lumbar vertebral discs: in vivo measurements at 3.0 T in healthy volunteers and patients with low back pain

Background context¹H magnetic resonance imaging (MRI) of the spine can rule out common causes of low back pain (LBP), such as disc protrusions or nerve root compression; however, no significant causal relation exists between morphology and the extent of symptoms. Functional MRI techniques, such as ²³Na, may provide additional information, allowing indirect assessment of vertebral glycosaminoglycan concentrations, decreases in which are associated with early degenerative changes.PurposeTo evaluate ²³Na-MRI of asymptomatic healthy volunteers and symptomatic patients with LPB and correlate the results to the Pfirrmann classification of MRI disc morphology.Study designRetrospective cohort study at an academic medical center.Patient sampleTwo groups were studied: (1) 55 healthy volunteers (31 men, 24 women; mean age 28.8 years) and (2) 12 patients (6 men, 6 women; mean age: 35.3 years) with a recent history of LBP.MethodsLumbar spines of the aforementioned groups were examined on a 3.0 T MRI scanner with morphological ¹H and ²³Na imaging. Intervertebral disc (IVD) ²³Na at each level was normalized (²³Na_norm). Distribution and differences between mean ²³Na_norm corresponding to each Pfirrmann classification were evaluated in the two study groups (analysis of variance). Linear correlations between ²³Na_norm, body mass index (BMI), and age were assessed (Pearson correlation coefficient). Gender-dependent differences were evaluated (paired t test).Outcome measuresPhysiological measure: IVD ²³Na_norm as determined by ²³Na-MRI.ResultsA normal distribution of ²³Na_norm was confirmed for both groups (p=.072 and p=.073, respectively). The mean Pfirrmann score statistically significantly differed between them (p<.0001). ²³Na_norm was statistically significantly reduced in degenerated IVDs (Pfirrmann scores 4+5) (p<.0001). No statistically significant differences were seen for the mean ²³Na_norm of IVDs with the same Pfirrmann score in healthy volunteers and patients (.469<p<.967). Age (0.007<R²<0.202) and BMI (0.074<R²<0.288) showed either weak or no correlation to ²³Na_norm. Mean ²³Na_norm was significantly (p=.0002) greater in women relative to men.ConclusionsThe results underline the feasibility and robustness of ²³Na-MRI of human IVDs and affirm, in a large cohort, decreases in ²³Na IVD content seen with disc degeneration.