Cost analysis of risperidone long-acting injection in the treatment of schizophrenia and schizoaffective disorders in Hong Kong: An approach using generalised estimating equations

Schizophrenia is one of the most expensive psychiatric illnesses. This study compared retrospectively health-care resources consumed 12 months before and 24 months after risperidone long-acting injection (RLAI) treatment in Hong Kong. A mirror-image analysis was conducted using data (N=191) from three public hospitals in Hong Kong from 2003 to 2007. The main outcome measure was hospitalisation cost. Other secondary outcomes such as hospitalisation episodes, outpatient visits and adverse events were also compared. A predictive model was established using linear regression based on generalised estimating equations. Analysis showed that RLAI was associated with a reduction in hospitalisation cost by HK$10,001,390 (24.7%) (HK$40,418,694 vs. HK$30,417,303; P-value <0.05). Days of hospitalisation were reduced by 1538 days (10.1%) (15,271 vs. 13,733; P-value <0.05). The predictive model estimated that the hospitalisation cost of patients using RLAI was only 11.1% (3.1–3.93%, 95% confidence interval (CI)) compared to those receiving conventional antipsychotics combined with oral risperidone. Cost of hospitalisation was significantly reduced after RLAI therapy. However, results should be considered as indicative or suggestive only, due to potential channelling bias where certain drug regimens are preferentially prescribed to patients with particular conditions. The findings from our study may be useful in health-care decision making considering treatment options for schizophrenia in resource-limited settings.     

Isolation of tumor spheres and mesenchymal stem-like cells from a single primitive neuroectodermal tumor specimen

Purpose

It has been reported that cancer stem cells (CSCs) can be isolated from primitive neuroectodermal tumor (PNET) specimens. Moreover, mesenchymal stem-like cells (MSLCs) have been isolated from Korean glioma specimens. Here, we tested whether tumor spheres and MSLCs can be simultaneously isolated from a single PNET specimen, a question that has not been addressed.

Methods

We isolated single-cell suspensions from PNET specimens, then cultured these cells using methods for MSLCs or CSCs. Cultured cells were analyzed for surface markers of CSCs using immunocytochemistry and for surface markers of bone marrow-derived mesenchymal stem cells (BM-MSCs) using fluorescence-activated cell sorting (FACS). Tumor spheres were exposed to neural differentiation conditions, and MSLCs were exposed to mesenchymal differentiation conditions. Possible locations of MSLCs within PNET specimens were determined by immunofluorescence analysis of tumor sections.

Results

Cells similar to tumor spheres and MSLCs were independently isolated from one of two PNET specimens. Spheroid cells, termed PNET spheres, were positive for CD133 and nestin, and negative for musashi and podoplanin. PNET spheres were capable of differentiation into immature neural cells and astrocytes, but not oligodendrocytes or mature neural cells. FACS analysis revealed that adherent cells isolated from the same PNET specimen, termed PNET-MSLCs, had surface markers similar to BM-MSCs. These cells were capable of mesenchymal differentiation. Immunofluorescence labeling indicated that some CD105⁺ cells might be closely related to endothelial cells and pericytes.

Conclusion

We showed that both tumor spheres and MSLCs can be isolated from the same PNET specimen. PNET-MSLCs occupied a niche in the vicinity of the vasculature and could be a source of stroma for PNETs.     

Transventricular endoscopic biopsy of suprasellar tumors: a pediatric case series

Background and purpose

The purpose of this study was to investigate the efficacy and safety of transventricular neuroendoscopic biopsies in pediatric patients with suprasellar tumors.

Methods

Twenty-three pediatric patients (12 males and 11 females) with suprasellar tumors underwent transventricular neuroendoscopic biopsy at our institute by a single surgeon from 2000 to 2011. Neuronavigation has been combined with endoscopic procedures since 2008. Neuroendoscopic biopsies were performed to verify the histopathological diagnosis of neoplasms and to plan appropriate treatment strategies.

Results

Neuroendoscopic biopsy specimens were appropriate for diagnosis in 22 of the 23 patients (95.7 %) and revealed 14 germ cell tumors (12 germinomas, one choriocarcinoma, and one immature teratoma), seven astrocytomas, and one craniopharyngioma. Subsequent treatment modalities including chemotherapy, radiation therapy, or microscopic surgery were determined according to the pathological findings. Seventeen of the 23 patients (73.9 %) showed ventriculomegaly. Among them, ventriculomegaly in 14 patients was resolved after an endoscopic procedure and/or adjuvant chemotherapy, but the remaining three patients (17.6 %) required a ventriculoperitoneal shunt to relieve the ventriculomegaly. The pathologic diagnosis of these three patients was uniformly a large astrocytoma. Navigational tracking was helpful to enter small ventricles and the narrow foramen of Monro in patients without hydrocephalus. No mortalities were related to the procedures, but three transient diabetes insipidus (13.0 %) cases occurred but fully recovered before the patients received adjuvant therapy.

Conclusion

Endoscopic biopsy is feasible and shows acceptable operation-related complications to obtain tissue from suprasellar tumors in pediatric patients. Navigation-assisted neuroendoscopic procedure improves the accuracy of the endoscopic approach. An associated endoscopic procedure can resolve hydrocephalus, but it has limitations with large ventricle-occupying tumors.     

Spatial Characteristics of White Matter Abnormalities in Schizophrenia

There is considerable evidence implicating brain white matter (WM) abnormalities in the pathophysiology of schizophrenia; however, the spatial localization of WM abnormalities reported in the existing studies is heterogeneous. Thus, the goal of this study was to quantify the spatial characteristics of WM abnormalities in schizophrenia. One hundred and fourteen patients with schizophrenia and 138 matched controls participated in this multisite study involving the Universities of Iowa, Minnesota, and New Mexico, and the Massachusetts General Hospital. We measured fractional anisotropy (FA) in brain WM regions extracted using 3 different image-processing algorithms: regions of interest, tract-based spatial statistics, and the pothole approach. We found that FA was significantly lower in patients using each of the 3 image-processing algorithms. The region-of-interest approach showed multiple regions with lower FA in patients with schizophrenia, with overlap at all 4 sites in the corpus callosum and posterior thalamic radiation. The tract-based spatial statistic approach showed (1) global differences in 3 of the 4 cohorts and (2) lower frontal FA at the Iowa site. Finally, the pothole approach showed a significantly greater number of WM potholes in patients compared to controls at each of the 4 sites. In conclusion, the spatial characteristics of WM abnormalities in schizophrenia reflect a combination of a global low-level decrease in FA, suggesting a diffuse process, coupled with widely dispersed focal reductions in FA that vary spatially among individuals (ie, potholes).Key words: diffusion tensor imaging, fractional anisotropy, pothole, tract-based spatial statistics     

A randomized open-label observational study to compare the efficacy and tolerability between topiramate and valproate in juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is managed with valproate in most patients; however, valproate is an antiepileptic drug that has relatively severe adverse effects, especially in women. We performed a prospective, open-label, randomized observational study for comparison of efficacy and tolerability between topiramate and valproate in patients with JME. The inclusion criteria were patients with newly diagnosed JME or previously diagnosed JME with a history of a poor response or adverse effects to other antiepileptic drugs. The primary endpoint of this study was percentage of patients who were free of myoclonic seizures for 24 weeks in the two groups. The frequency and severity of adverse effects were also assessed. Sixteen patients were randomized to topiramate and 17 to valproate. In the topiramate arm, 11 of 16 patients (68.9%) completed 24-week maintenance therapy and seven of the 11 (64%) were seizure-free. In the valproate arm, 16 of 17 patients (94.1%) completed 24-week follow-up and nine of 16 (56%) were seizure-free. The difference (64% topiramate versus 56% valproate) did not reach statistical significance in this study group (p = 0.08, Fisher’s exact test). However, the severity of adverse effects was significantly different. Only 1 of 10 adverse effects from topiramate was ranked moderate-to-severe (10%), in comparison with severe rankings for 10 of 17 adverse effects from valproate (59%) (p = 0.018, Fisher’s exact test). In summary, the efficacy of topiramate and valproate was not different, but the severity of adverse effects was favourable for topiramate. Our findings suggest that valproate may be replaced with topiramate, especially for the patients with JME who do not tolerate valproate.     

Association between gout and vertigo in a Taiwanese population

There are reports of an association between benign paroxysmal positional vertigo and hyperuricemia. We sought to determine the risk of vertigo among patients with gout compared with the general population, using a nationwide Taiwanese population-based claims database. Our study cohort consisted of patients with a diagnosis of gout disorders in 2004 (N = 18 773). Four age- and gender-matched controls for every patient in the study cohort were selected using random sampling as the comparison cohort (N = 75 092). All subjects were followed from the date of cohort entry until they developed vertigo or to the end of 2006. Cox proportional hazard regressions were performed to evaluate the 3-year vertigo-free survival rates. Of the total sample, 2563 (incidence, 10.09 per 1000 person-years) had vertigo during the 3-year follow-up period: 570 (incidence, 11.78 per 1000 person-years) from the study cohort and 1993 (incidence, 9.69 per 1000 person-years) from the comparison cohort. The adjusted hazard ratios (HR) of peripheral and central vertigo in patients with gout compared with controls during the 2–3-year follow-up were 1.17 (95% confidence interval [CI] = 1.05–1.29, p = 0.003) and 1.08 (95% CI = 0.86–1.36, p = 0.53), respectively. This is the first population-based study performed to suggest that patients with gout may have an increased risk of peripheral vertigo but not central vertigo. Benign paroxysmal positional vertigo may be the reason for the observed association; however, future studies are required to further ascertain the relationship between gout and the various causes of peripheral vertigo.     

Electrophysiological and behavioral effects of group III metabotropic glutamate receptors on pallidal neurons in normal and parkinsonian rats

The globus pallidus plays a critical role in movement regulation. Glutamate being an important excitatory neurotransmitter modulates the activity of pallidal neurons through both ionotropic and metabotropic glutamate receptors (mGluRs). Morphological studies have shown that group III mGluRs are generally located presynaptically in the globus pallidus. Up to now, little is known about the in vivo electrophysiological effects of group III mGluRs on the pallidal neurons. This study investigated the electrophysiological and behavioral effects of group III mGluRs on pallidal neurons in both normal and 6‐hydroxydopamine (6‐OHDA) lesioned parkinsonian rats. Micropressure ejection of group III mGluR agonist, l ‐2‐amino‐4‐phosphonobutyrate (l ‐AP4), increased or decreased the firing rate of pallidal neurons in both normal and parkinsonian rats. The l ‐AP4‐induced excitatory effects on the lesioned side of parkinsonian rats (117.4 ± 17.2%) were stronger than that in normal rats (64.3 ± 10.1%). While the proportion of neurons that were unresponsive to l ‐AP4 on the lesioned side of parkinsonian rats (50%) was more than that of normal rats (13%). Unilateral microinjection of l ‐AP4 into the globus pallidus induced a contralateral dystonic posturing in the presence of systemic haloperidol administration. The selective group III mGluRs antagonist, (RS)‐α‐cyclopropyl‐4‐phosphonophenylglycine, had no effect on pallidal neurons when used alone and could block both l ‐AP4‐induced electrophysiological and behavioral effects. Combining electrophysiological and behavioral findings, we concluded that activation of group III mGluRs modulate the activity of pallidal neurons under both normal and parkinsonian state. Synapse 67:831–838, 2013 . © 2013 Wiley Periodicals, Inc.     

Recent developments in conducting polymers: applications for electrochemistry

Scientists have categorized conductive polymers as materials having strongly reversible redox behavior and uncommon combined features of plastics and metal. Because of their multifunctional characteristics, e.g., simplistic synthesis, acceptable environmental stability, beneficial optical, electronic, and mechanical features, researchers have largely considered them for diverse applications. Therefore, their capability of catalyzing several electrode reactions has been introduced as one of their significant features. A thin layer of the conducting polymer deposited on the substrate electrode surface can augment the electrode process kinetics of several solution species. Such electrocatalytic procedures with modified conducting polymer electrodes can create beneficial utilization in diverse fields of applied electrochemistry. This review article explores typical recent applications of conductive polymers (2016–2020) as active electrode materials for energy storage applications, electrochemical sensing, and conversion fields such as electrochemical supercapacitors, lithium-ion batteries, fuel cells, and solar cells.

Scientists have categorized conductive polymers as materials having strongly reversible redox behavior and uncommon combined features of plastics and metal.