Virtual Reality as a Method to Cope With Labor Pain: What Do Women Want?

This study aimed to determine what childbearing women want when using virtual reality as an intrapartum pain management method. Researchers performed a qualitative exploratory study using content analysis. Two focus groups were organized including pregnant women anticipating a vaginal birth and women who recently had given birth, no longer than 6 months ago. The focus groups included a 30-minute virtual reality demo. In total, 10 women participated. Five themes emerged: (1) "try, test and explore": the need to receive information and to get acquainted with virtual reality during the antenatal period; (2) "variety and diversity in physical and digital options": the preference for a variety in virtual content and view virtual reality as a complementary method to methods for intrapartum pain management; (3) "distraction versus focus": virtual reality as a method to distract from pain, from the clinical context or to help them focus; (4) "comfort both physical and digital": measures to ensure a comfortable physical and virtual experience; and (5) "birthing partner": the potential need to include partners. This study is an essential step informing the development, implementation, and research of labor-specific virtual reality and informing antenatal healthcare providers when offering women virtual reality as intrapartum pain management.

Zonisamide attenuates lactacystin-induced parkinsonism in mice without affecting system xc.

Zonisamide (ZNS), an anticonvulsant drug exhibiting symptomatic effects in Parkinson's disease (PD), was recently reported to exert neuroprotection in rodent models. One of the proposed neuroprotective mechanisms involves increased protein expression of xCT, the specific subunit of the cystine/glutamate antiporter system xc-, inducing glutathione (GSH) synthesis. Here, we investigated the outcome of ZNS treatment in a mouse model of PD based on intranigral proteasome inhibition, and whether the observed effects would be mediated by system xc-. The proteasome inhibitor lactacystin (LAC) was administered intranigrally to male C57BL/6J mice receiving repeated intraperitoneal injections of either ZNS 30mgkg-1 or vehicle. Drug administration was initiated three days prior to stereotaxic LAC injection and was maintained until six days post-surgery. One week after lesion, mice were behaviorally assessed and investigated in terms of nigrostriatal neurodegeneration and molecular changes at the level of the basal ganglia, including expression levels of xCT. ZNS reduced the loss of nigral dopaminergic neurons following LAC injection and the degree of sensorimotor impairment. ZNS failed, however, to modulate xCT expression in basal ganglia of lesioned mice. In a separate set of experiments, the impact of ZNS treatment on system xc- was investigated in control conditions in vivo as well as in vitro. Similarly, ZNS did not influence xCT or glutathione levels in naive male C57BL/6J mice, nor did it alter system xc- activity or glutathione content in vitro. Taken together, these results demonstrate that ZNS treatment provides neuroprotection and behavioral improvement in a PD mouse model based on proteasome inhibition via system xc- independent mechanisms.

Miniaturized ultra-high performance liquid chromatography coupled to electrochemical detection: Investigation of system performance for neurochemical analysis.

The interest in implementation of miniaturized ultra-high performance liquid chromatography (UHPLC) in neurochemical research is growing because of the need for faster, more selective and more sensitive neurotransmitter analyses. The instrument performance of a tailor designed microbore UHPLC system coupled to electrochemical detection (ECD) is investigated, focusing on the quantitative monoamine determination in in vivo microdialysis samples. The use of a microbore column (1.0mm I.D.) requires miniaturization of the entire instrument, though a balance between extra-column band broadening and injection volume must be considered. This is accomplished through the user defined Performance Optimizing Injection Sequence, whereby 5 µL sample is injected on the column with a measured extra-column variance of 4.5-9.0 µL(2) and only 7 µL sample uptake. Different sub-2 µm and superficially porous particle stationary phases are compared by means of the kinetic plot approach. Peak efficiencies of about 16000-35000 theoretical plates are obtained for the Acquity UPLC BEH C18 column within 13 min analysis time. Furthermore, the coupling to ECD is shown suitable for microbore UHPLC analysis thanks to the miniaturized flow cell design, sufficiently fast data acquisition and mathematical data filtering. Ultimately, injection of in vivo samples demonstrates the applicability of the system for microdialysis analysis.

Reassessment of the antioxidative mixture for the challenging electrochemical determination of dopamine, noradrenaline and serotonin in microdialysis samples.

In recent years, the simultaneous monitoring of the monoamine neurotransmitters dopamine, noradrenaline and serotonin in vivo is advancing due to innovations in miniaturized and fast chromatographic techniques. However, the determination of the most hydrophilic compound, noradrenaline, in microdialysis samples by (ultra-)high performance liquid chromatography ((U)HPLC) with electrochemical detection (ECD) is impeded by a broad solvent front, caused by the addition of antioxidative agents. Hence, an elaborate reassessment of currently used antioxidative mixtures is necessary for further analytical improvements. The proposed mixture, containing 100mM acetic acid, 0.27mM Na2EDTA and 12.5µM ascorbic acid (pH 3.2), is less complex than previously described mixtures and shows minimal ECD interference. It stabilizes the three monoamines in standard solutions and in microdialysis samples, considering both autosampler stability at 4°C for 48h and long term stability at -20°C for a duration of six months. An in vivo microdialysis experiment demonstrates the possibility to monitor changes in extracellular levels of the three monoamines simultaneously in the rat hippocampus with UHPLC-ECD using the optimized antioxidative mixture.

Validation of the 6 Hz refractory seizure mouse model for intracerebroventricularly administered compounds.

The six hertz (6 Hz) refractory seizure model is considered an indispensable chain of the Anticonvulsant Screening Project. We here describe an adapted protocol using the intracerebroventricular (i.c.v.) delivery route, which will allow researchers to perform targetvalidation or proof-of-principle studies using promising compounds with unknown or limited blood-brain barrier permeability (e.g. neuropeptides and peptidomimetics) in this model. Seizures were induced by single application of a current intensity of 49 mA to i.c.v.-implanted NMRI mice using an ECT Unit 57800 Ugo Basile stimulator. By applying these key parameters, c-Fos immunohistochemistry revealed the recruitment of the dentate gyrus, ratifying this model as a valuable tool for testing i.c.v. administered compounds against therapy-resistant seizures. This finding was further strengthened, since i.c.v. administration of levetiracetam suppressed 6 Hz-evoked seizure severity but sodium phenytoin did not. We also propose to use "seizure duration" as an alternative, accurate parameter to express the results within this model.

An ultrasensitive nano UHPLC-ESI-MS/MS method for the quantification of three neuromedin-like peptides in microdialysates.

AIM: An ultrasensitive nano UHPLC-ESI-MS/MS method is developed to simultaneously monitor three low-concentration neuromedin-like peptides in microdialysates. RESULTS: Peptide preconcentration and sample desalting is performed online on a trap column. A shallow gradient slope at 300 nl/min on the analytical column maintained at 35°C, followed by two saw-tooth column wash cycles, results in the highest sensitivity and the lowest carryover. The validated method allows the accurate and precise quantification of 0.5 pM neurotensin and neuromedin N (2.5 amol on column), and of 3.0 pM neuromedin B (15.0 amol on column) in in vivo microdialysates without the use of internal standards. CONCLUSION: The assay is an important tool for elucidating the role of these neuromedin-like peptides in the pathophysiology of neurological disorders.

Improved sensitivity of the nano ultra-high performance liquid chromatography-tandem mass spectrometric analysis of low-concentrated neuropeptides by reducing aspecific adsorption and optimizing the injection solvent.

Obtaining maximal sensitivity of nano UHPLC-MS/MS methods is primordial to quantify picomolar concentrations of neuropeptides in microdialysis samples. Since aspecific adsorption of peptides to Eppendorf tubes, pipette tips and UHPLC vials is detrimental for method sensitivity, a strategy is presented to reduce adsorption of these peptides during standard preparation. Within this respect, all procedural steps from dissolution of the lyophilized powder until the injection of the sample onto the system are investigated. Two peptides of the neuromedin family, i.e. neuromedin B and neuromedin N, and a neuromedin N-related neuropeptide, neurotensin, are evaluated. The first part of this study outlines a number of parameters which are known to affect peptide solubility. The main focus of the second part involves the optimization of the sample composition in the UHPLC vial by using design of experiments. Contradictory findings are observed concerning the influence of acetonitrile, salts and matrix components. They are found important for injection of the peptides into the system, but crucially need to be excluded from the dilution solvent. Furthermore, the type of surface material, temperature and the pipetting protocol considerably affect the adsorption phenomenon. Statistical analysis on the results of the central composite design reveals that the highest peptide responses are obtained with the injection solvent consisting of 13.1% V/V ACN and 4.4% V/V FA. This aspect of the optimization strategy can be identified as the main contributor to the gain in method sensitivity. Since the reduction of peptide adsorption and the optimization of the injection solvent resulted in a clear and quantifiable signal of the three peptides, optimization of both issues should be considered in the early stage of method development, in particular when the analysis of low-concentration peptide solutions is envisaged.

Strategies to reduce aspecific adsorption of peptides and proteins in liquid chromatography-mass spectrometry based bioanalyses: an overview.

In the drug-discovery setting, the development of new peptide and protein-based biopharmaceuticals attracts increased attention from the pharmaceutical industry and consequently demands the development of high-throughput LC-MS methods. Regulatory guidelines require bioanalytical methods to be validated not only in terms of linearity, sensitivity, accuracy, precision, selectivity and stability, but also in terms of carryover. Carryover results from the aspecific adsorption of analyte(s) to parts of the analytical system and thus introduces bias in both identification and quantification assays. Moreover, nonspecific binding occurs at the surface of materials used during sample preparation, such as pipette tips, sample tubes and LC-vials. Hence, linearity, sensitivity and repeatability of the analyses are negatively affected. Due to the great diversity in physicochemical properties of biomolecules, there is no general approach available to minimize adsorption phenomena. Therefore, we aim to present different strategies which can be generically applied to reduce nonspecific binding of peptides and proteins. In the first part of this review, a systematic approach is proposed to guide the reader through the different solvents which can be used to dissolve the analyte of interest. Indeed, proper solubilization is one of the most important factors for a successful analysis. In addition, alternative approaches are described to improve analyte recovery from the sample vial. The second part focuses on strategies to efficiently reduce adsorption at components of the autosampler, column and mass spectrometer. Thereby carryover is reduced while maintaining a sufficiently wide dynamic range of the assay.

Ion-pair ultra-high performance liquid chromatographic analysis of monoamines: peak-splitting at high flow rates.

The use of ion-pair ultra-high performance liquid chromatography (UHPLC) coupled with electrochemical detection (ECD) is of great interest for the fast and sensitive determination of the monoamine neurotransmitters dopamine, noradrenaline and serotonin in microdialysis samples. However, when applying high flow rates in ion-pair UHPLC, other peaks than the initial compound peaks appear on the chromatogram. This peak-splitting phenomenon is caused by disturbed ion-pair retention mechanisms. The influence of several chromatographic parameters is investigated. Peak-splitting is delayed to higher flow rates when increasing the concentration of ion-pair reagent or buffering agent in the mobile phase, when decreasing the percentage of organic modifier in the mobile phase, when applying a stationary phase with a smaller amount of packing material or when increasing the separation temperature. One or a combination of these conditions can be applied to analyze the monoamine neurotransmitters using ion-pair UHPLC-ECD at high flow rates.

The absolute quantification of endogenous levels of brain neuropeptides in vivo using LC-MS/MS.

Neuropeptides seem to play an important role when the CNS is challenged. In order to obtain better insights into the central peptidergic effects, it is essential to monitor their concentration in the brain. Quantification of neuropeptides in dialysates is challenging due to their low extracellular concentrations (low pM range), their low microdialysis efficiencies, the need for acceptable temporal resolution, the small sample volumes, the complexity of the matrix and the tendency of peptides to stick to glass and polymeric materials. The quantification of neuropeptides in dialysates therefore necessitates the use of very sensitive nano-LC-MS/MS methods. A number of LC-MS/MS and microdialysis parameters need to be optimized to achieve maximal sensitivity. The optimized and validated methods can be used to investigate the in vivo neuropeptide release during pathological conditions, in this way initiating new and immense challenges for the development of new drugs.