Restoration of Vision in the pde6β-deficient Dog,a Large Animal Model of Rod-cone Dystrophy

Defects in the β subunit of rod cGMP phosphodiesterase 6 (PDE6β) are associated with autosomal recessive retinitis pigmentosa (RP), a childhood blinding disease with early retinal degeneration and vision loss. To date, there is no treatment for this pathology. The aim of this preclinical study was to test recombinant adeno-associated virus (AAV)-mediated gene addition therapy in the rod-cone dysplasia type 1 (rcd1) dog, a large animal model of naturally occurring PDE6β deficiency that strongly resembles the human pathology. A total of eight rcd1 dogs were injected subretinally with AAV2/5RK.cpde6β (n = 4) or AAV2/8RK.cpde6β (n = 4). In vivo and post-mortem morphological analysis showed a significant preservation of the retinal structure in transduced areas of both AAV2/5RK.cpde6β- and AAV2/8RK.cpde6β-treated retinas. Moreover, substantial rod-derived electroretinography (ERG) signals were recorded as soon as 1 month postinjection (35% of normal eyes) and remained stable for at least 18 months (the duration of the study) in treated eyes. Rod-responses were undetectable in untreated contralateral eyes. Most importantly, dim-light vision was restored in all treated rcd1 dogs. These results demonstrate for the first time that gene therapy effectively restores long-term retinal function and vision in a large animal model of autosomal recessive rod-cone dystrophy, and provide great promise for human treatment.     

Successful Gene Therapy in the RPGRIP1-deficient Dog: a Large Model of Cone–Rod Dystrophy

For the development of new therapies, proof-of-concept studies in large animal models that share clinical features with their human counterparts represent a pivotal step. For inherited retinal dystrophies primarily involving photoreceptor cells, the efficacy of gene therapy has been demonstrated in canine models of stationary cone dystrophies and progressive rod–cone dystrophies but not in large models of progressive cone–rod dystrophies, another important cause of blindness. To address the last issue, we evaluated gene therapy in the retinitis pigmentosa GTPase regulator interacting protein 1 (RPGRIP1)-deficient dog, a model exhibiting a severe cone–rod dystrophy similar to that seen in humans. Subretinal injection of AAV5 (n = 5) or AAV8 (n = 2) encoding the canine Rpgrip1 improved photoreceptor survival in transduced areas of treated retinas. Cone function was significantly and stably rescued in all treated eyes (18–72% of those recorded in normal eyes) up to 24 months postinjection. Rod function was also preserved (22–29% of baseline function) in four of the five treated dogs up to 24 months postinjection. No detectable rod function remained in untreated contralateral eyes. More importantly, treatment preserved bright- and dim-light vision. Efficacy of gene therapy in this large animal model of cone–rod dystrophy provides great promise for human treatment.     

Effect of Endostar Combined with Gemcitabine on the Mouse Model of Human Pancreatic Cancer

Objective To investigate the effects of recombinant human endostatin, that is, endostar combined with gemcitabine on the mouse model of human pancreatic cancer. Methods We use the cell line PANC-1 and the severe combined immune deficient mice to set up the mouse model of human pancreatic cancer, then devide them into three groups, treat them with gemcitabine, gemcitabine combined with endostar, and 0.9 % saline water respectively. We observe the change of the tumor volumn, use ELISA method to detect the serum VEGF level, stain the micro vessel in the tumor tissue with immunohistochemistry method, and compare the data among the different groups respectively. Results On the twenty-eighth day, the tumor volume of the control group, the monotherapy group and the combination group, averaged 1 700 mm^3, 19. 2 mm^3, 10.4 mm^3, serum VEGF level 88.6 L, 35.5, 26.3 pg/mL and MVD 43.9, 30.3, 19. 2 respectively, which had significant difference. Conclusion Endostar can strengthen the lethal effect of gemcitabine on the mouse model of human pancreatic cancer.     

Effect of Endostar Combined with Gemcitabine on the Mouse Model of Human Pancreatic Cancer

IntroductionPancreatic canceris an unsolved health problem.The 5-year survival rateis only 3%and median over-all survival is<6 months,a situationthat has remained unchangedfor the past three decades.Surgical re-sectionis the only potentially curative ther…     

Utility of Homeostasis Model Assessment of ��-Cell Function in Predicting Diabetes in 12,924 Healthy Koreans

OBJECTIVE

It is unclear how well homeostasis model assessment of β-cell function (HOMA-β) predicts diabetes development beyond its components, especially glucose.

RESEARCH DESIGN AND METHODS

We identified 12,924 nondiabetic Koreans who had fasting plasma glucose and insulin concentrations measured in 2003 and again in 2008. To minimize the impact of differences in baseline glucose concentration, individuals were divided into three glucose categories: normal fasting glucose (NFG, glucose <5.6 mmol/l), impaired fasting glucose (IFG-100) (5.6–6.0 mmol/l), and IFG-110 (6.1–6.9 mmol/l).

RESULTS

Diabetes developed in 29% of individuals in the IFG-110 group, compared with 5% in IFG-100 and 0.3% in NFG groups. Within each glucose category, those who progressed to diabetes had higher baseline glucose concentrations (P ≤ 0.04). Baseline HOMA-β, however, was not lower but higher in individuals who developed diabetes in the NFG group (P = 0.009) and similar in the IFG-100 and IFG-110 groups.

CONCLUSIONS

These data question the utility of using HOMA-β to predict the development of diabetes.The homeostasis model assessment of β-cell function (HOMA-β) is an index of insulin secretory function derived from fasting plasma glucose and insulin concentrations (1). It has been used to predict diabetes development in nondiabetic individuals in four studies (2–5), and the conclusion in each instance was that a decrease in insulin secretory function, as estimated by HOMA-β, predicted the development of diabetes and/or impaired glucose tolerance. However, because it was also shown in these studies that baseline glucose concentration was higher in individuals who developed diabetes, it could be argued that the lower values for HOMA-β may only be reflecting the difference in glucose concentration. The current analysis was initiated to see if HOMA-β provided a more sensitive assessment of the likelihood of developing type 2 diabetes than did knowledge of individual fasting plasma glucose and insulin concentrations.     

Positron Emission Tomography of Copper Metabolism in the Atp7b ?/? Knock-out Mouse Model of Wilson’s Disease

Purpose  

This study aims to determine feasibility and utility of copper-64(II) chloride (⁶⁴CuCl₂) as a tracer for positron emission tomography (PET) of copper metabolism imbalance in human Wilson’s disease (WD).     

Astroglial Responses to Amyloid-Beta Progression in a Mouse Model of Alzheimer’s Disease

Purpose

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by amyloid-beta (Aβ) deposition, hyperphosphorylation of tau, and neuroinflammation. Astrocytes, the most abundant glial cell type in the nervous system, respond to neurodegenerative disorders through astrogliosis, i.e., converting to a reactive inflammatory state. The aim of this study was to investigate how in vivo quantification of astrogliosis using positron emission tomography (PET) radioligand deuterium-l-[¹¹C]deprenyl ([¹¹C]DED), binding to enzyme monoamine oxidase-B (MAO-B) which is overexpressed in reactive astrocytes during AD, corresponds to expression of glial fibrillary acidic protein (GFAP) and vimentin, i.e., two well-established markers of astrogliosis, during Aβ pathology progression.

Procedures

APP_ArcSwe mice (n = 37) and wild-type (WT) control mice (n = 23), 2–16-month old, were used to investigate biomarkers of astrogliosis. The radioligand, [¹¹C]DED, was used as an in vivo marker while GFAP, vimentin, and MAO-B were used to investigate astrogliosis and macrophage-associated lectin (Mac-2) to investigate microglia/macrophage activation by immunohistochemistry of the mouse brain. Aβ and GFAP levels were also measured with ELISA in brain homogenates.

Results

The intrabrain levels of aggregated Aβ and reactive astrocytes were found to be elevated in APP_ArcSwe compared with WT mice. GFAP and vimentin expression increased with age, i.e., with Aβ pathology, in the APP_ArcSwe mice. This was not the case for in vivo marker [¹¹C]DED that showed elevated binding of the same magnitude in APP_ArcSwe mice compared with WT mice at both 8 and 16 months. Further, immunohistochemistry indicated that there was limited co-expression of MAO-B and GFAP.

Conclusions

MAO-B levels are increased early in Aβ pathology progression, while GFAP and vimentin appear to increase later, most likely as a consequence of abundant Aβ plaque formation. Thus, [¹¹C]DED is a useful PET radioligand for the detection of changes in MAO-B at an early stage of AD progression but does not measure the total extent of astrogliosis at advanced stages of Aβ pathology.

     

Combinations of β-Lactam Antibiotics Currently in Clinical Trials Are Efficacious in a DHP-I-Deficient Mouse Model of Tuberculosis Infection

We report here a dehydropeptidase-deficient murine model of tuberculosis (TB) infection that is able to partially uncover the efficacy of marketed broad-spectrum β-lactam antibiotics alone and in combination. Reductions of up to 2 log CFU in the lungs of TB-infected mice after 8 days of treatment compared to untreated controls were obtained at blood drug concentrations and time above the MIC (T_>MIC) below clinically achievable levels in humans. These findings provide evidence supporting the potential of β-lactams as safe and mycobactericidal components of new combination regimens against TB with or without resistance to currently used drugs.     

Acat1 Knockdown Gene Therapy Decreases Amyloid-β in a Mouse Model of Alzheimer's Disease

Both genetic inactivation and pharmacological inhibition of the cholesteryl ester synthetic enzyme acyl-CoA:cholesterol acyltransferase 1 (ACAT1) have shown benefit in mouse models of Alzheimer''s disease (AD). In this study, we aimed to test the potential therapeutic applications of adeno-associated virus (AAV)-mediated Acat1 gene knockdown in AD mice. We constructed recombinant AAVs expressing artificial microRNA (miRNA) sequences, which targeted Acat1 for knockdown. We demonstrated that our AAVs could infect cultured mouse neurons and glia and effectively knockdown ACAT activity in vitro. We next delivered the AAVs to mouse brains neurosurgically, and demonstrated that Acat1-targeting AAVs could express viral proteins and effectively diminish ACAT activity in vivo, without inducing appreciable inflammation. We delivered the AAVs to the brains of 10-month-old AD mice and analyzed the effects on the AD phenotype at 12 months of age. Acat1-targeting AAV delivered to the brains of AD mice decreased the levels of brain amyloid-β and full-length human amyloid precursor protein (hAPP), to levels similar to complete genetic ablation of Acat1. This study provides support for the potential therapeutic use of Acat1 knockdown gene therapy in AD.     

A Nonazole CYP51 Inhibitor Cures Chagas’ Disease in a Mouse Model of Acute Infection

Chagas’ disease, the leading cause of heart failure in Latin America, is caused by the kinetoplastid protozoan Trypanosoma cruzi. The sterols of T. cruzi resemble those of fungi, both in composition and in biosynthesis. Azole inhibitors of sterol 14α-demethylase (CYP51) successfully treat fungal infections in humans, and efforts to adapt the success of antifungal azoles posaconazole and ravuconazole as second-use agents for Chagas’ disease are under way. However, to address concerns about the use of azoles for Chagas’ disease, including drug resistance and cost, the rational design of nonazole CYP51 inhibitors can provide promising alternative drug chemotypes. We report the curative effect of the nonazole CYP51 inhibitor LP10 in an acute mouse model of T. cruzi infection. Mice treated with an oral dose of 40 mg LP10/kg of body weight twice a day (BID) for 30 days, initiated 24 h postinfection, showed no signs of acute disease and had histologically normal tissues after 6 months. A very stringent test of cure showed that 4/5 mice had negative PCR results for T. cruzi, and parasites were amplified by hemoculture in only two treated mice. These results compare favorably with those reported for posaconazole. Electron microscopy and gas chromatography-mass spectrometry (GC-MS) analysis of sterol composition confirmed that treatment with LP10 blocked the 14α-demethylation step and induced breakdown of parasite cell membranes, culminating in severe ultrastructural and morphological alterations and death of the clinically relevant amastigote stage of the parasite.Chagas’ disease, caused by the kinetoplastid protozoan Trypanosoma cruzi, is the leading cause of heart failure in Latin America. The disease is transmitted naturally by hematophagous reduviid insects (6), but human infection may also occur via other routes, including blood transfusion, congenital infection, breast-feeding, organ transplant from chagasic donors, laboratory accidents, and ingestion of contaminated foods and beverages. The acute phase of infection usually occurs in children, and 5 to 10% of symptomatic patients may die. Following a subclinical “indeterminate” phase, a chronic phase involving heart failure and gastrointestinal tract lesions often ensues (37, 42). The only clinically available drugs for Chagas’ disease are nifurtimox and benznidazole, both of which have been in use for 4 decades. While they have significant efficacy in the acute phase, both drugs suffer from the twin liabilities of serious side effects and low efficacy in the chronic phase. New drugs with improved efficacy and less toxicity are needed (14, 29).The biosynthesis of membrane sterols is one of the metabolic pathways successfully targeted in the treatment of diseases caused by pathogenic fungi (48). Clinically employed antifungal azoles target sterol 14α-demethylase (CYP51), a cytochrome P450 enzyme that catalyzes oxidative removal of the 14α-methyl group of a sterol precursor to result in Δ^14,15-desaturated intermediates in ergosterol biosynthesis (19, 20). Close similarities to fungi in sterol composition and biosynthesis, plus an absolute requirement for specific 24-methyl sterols for cell viability and proliferation, provide a basis for development of chemotherapy targeting the sterol biosynthetic pathway in T. cruzi. The successful application of antifungal drugs to anti-chagasic therapy exploits these similarities (38). In addition to compounds optimized for antifungal therapy, other CYP51 inhibitors with strong anti-T. cruzi activity have been reported (3, 8, 24, 44, 45).Inhibitors of CYP51 are in the pipeline for preclinical and clinical development for treatment of Chagas’ disease (11). Although earlier commercially available inhibitors, like ketoconazole and itraconazole, were not powerful enough to eradicate T. cruzi from infected animals or human patients (28), the recently approved inhibitor posaconazole (Noxafil; Schering-Plough) is capable of inducing parasitological cure in murine models of both acute and chronic Chagas’ disease (18). Posaconazole cured 50 to 100% of animals in the acute phase and 50 to 60% of chronically infected animals (2). Very recently, posaconazole cured an immunosuppressed patient with concomitant Chagas’ disease and systemic lupus erythematosus (34). However, the use of posaconazole as an anti-chagasic agent may be limited by the requirement for simultaneous intake of a fatty meal or a nutritional supplement to enhance absorption, the drug''s high cost, and the need for clinical monitoring during treatment (31). Another complication is the rapid appearance of laboratory-induced resistance to azoles in T. cruzi, which may predict the occurrence of drug resistance in chagasic patients (4). Although no data on the development of posaconazole resistance in patients with Chagas’ disease are available, studies of fungal infections indicate that posaconazole resistance occurs mainly by a mechanism involving mutation of the cyp51 gene (23, 33, 35). Posaconazole appears to be less susceptible to the efflux pumps that confer resistance to some other azoles (7, 25, 35). Mapping mutations in cyp51 genes in clinical posaconazole-resistant isolates on the CYP51-posaconazole structure (9) points to the mouth of the posaconazole binding tunnel as a mutation hot spot. Mutations of G54, P216, and M220 in clinical isolates of Aspergillus fumigatus (10, 12, 13, 23, 27, 32) (corresponding to G49, P210, and F214, respectively, in T. cruzi CYP51 [CYP51_Tc]) and of A61 (46) and P230 (25) in clinical isolates of Candida albicans (I45 and P210, respectively, in CYP51_Tc) map directly to the tunnel mouth, where amino acids interact with the dangling long substituent tail of posaconazole extending into the tunnel (9). Mutations of G54 in A. fumigatus to arginine or tryptophan associate with moderate and high levels of resistance, respectively, and confer cross-resistance between itraconazole and posaconazole (27). Mutations of M220 confer cross-resistance to all azole drugs tested, including itraconazole, voriconazole, ravuconazole, and posaconazole (30, 39), and therefore may interfere with the entry of the drugs. In accordance with this assumption, posaconazole is reported to induce resistance to all azole drugs in Candida parapsilosis in vitro (35). The alarming perspective emerging from antifungal therapy efforts must be taken into consideration when designing antichagasic drugs targeting CYP51_Tc. While antifungal azoles do show promise, the less than 30% sequence identity between fungal and protozoan CYP51 targets suggests that a more direct approach may be a better route toward developing novel potent therapeutic CYP51 inhibitors.Using clues from our previous work on CYP51 from Mycobacterium tuberculosis (CYP51_Mt), we focused on rationally designed nonazole inhibitors of CYP51_Tc. These inhibitors were based on an experimental hit obtained from screening a small-molecule-compound library against CYP51_Mt (36). Analysis of the X-ray structure revealed that the N-[4-pyridyl]-formamide scaffold group (Fig. ​(Fig.1A,1A, highlighted in gray) binds in the CYP51 active site via conserved residues and the heme prosthetic group. Structural characterization confirmed that these interactions in the complexes were preserved between CYP51_Mt and five different compounds (8, 36), suggesting that this scaffold could be used efficiently instead of the azole or triazole groups to target a variety of chemotypes to the CYP51 active site. Based on the similarity of the chemical structures, the expanded-spectrum compound LP10 (Fig. ​(Fig.1B)1B) was selected for its nanomolar binding affinity to CYP51_Tc and its potent efficacy against T. cruzi in mammalian cells (8). As the pyridyl group of LP10 presumably coordinates to the heme iron, the indole substituent may fill the space occupied by the 2,4-difluorophenyl ring of fluconazole or posaconazole in their structurally characterized complexes with CYP51 (9).Open in a separate windowFIG. 1.Screen hit (A) and the expanded-spectrum compound LP10 (B) containing the N-[4-pyridyl]-formamide scaffold (highlighted in gray), which unvaryingly binds in the CYP51 active site. The chiral center is labeled with an asterisk.In the present work, we evaluated the efficacy of LP10 in an animal model of acute Chagas’ disease. The curative effect of LP10 in vivo was comparable to that of the protease inhibitor K777, an antichagasic drug in preclinical development, used as a positive control (15, 16). Electron microscopy and gas chromatography-mass spectrometry (GC-MS) analysis demonstrated that treatment with LP10 disrupted cell membranes in T. cruzi amastigotes and altered sterol composition via accumulation of the C-14-methylated precursors lanosterol and 24-methylene-dihydrolanosterol (eburicol). There was concomitant reduction of 14-desmethylated fecosterol and episterol. LP10-induced alterations are consistent with the inhibition of T. cruzi CYP51.     

Lack of significant treatment effect of plasma exchange in the treatment of drug-induced toxic epidermal necrolysis?

Objective: Comparison of outcome in patients with toxic epidermal necrolysis (TEN) in patients who received plasma exchange (PE) compared with the results in two other centres that used almost identical treatment protocols but without PE.¶Design: Retrospective comparative case series with two recently published case series serving as controls.¶Setting: National burns intensive care unit (ICU) and Department of Transfusion Medicine at Linköping University Hospital, Sweden.¶Patients: 8 consecutive patients admitted with TEN who received PE during 1987–1997.¶Interventions: Neither prophylactic antibiotics nor cortisone were used. The patients were given a median of 5.5 PE treatments (range 1–8).¶Results: Eight patients with a median (range) age of 45 years (5–89) and with a median skin involvement total body surface area (TBSA) of 38 % (12–100) were treated. The length of stay in the burns ICU was 15 (13–25) days and the time from onset of the cutaneous signs until complete re-epithelialisation was 24 days (13–55) for the seven survivors. Five patients fulfilled the diagnostic criteria of sepsis. One patient with extensive ischaemic cardiac disease developed septic shock and died (mortality 12.5 %). Two patients developed side effects from PE.¶Conclusions: To our knowledge, this is the largest series yet presented using PE in the treatment of TEN. Our results, in patients with less cutaneous involvement, similar causative agents, and similar demographic data as in the other two studies (controls), were no different as far as mortality, length of stay, or time to re-epithelialisation were concerned. This finding does not support the use of PE in the treatment of TEN.     

Evaluation of the Relationship Between Cognitive Impairment,Glycometabolism, and Nicotinic Acetylcholine Receptor Deficits in a Mouse Model of Alzheimer’s Disease

Molecular Imaging and Biology - In patients with Alzheimer’s disease (AD), the loss of cerebral nicotinic acetylcholine receptors (nAChRs) that are implicated in higher brain functions has...     

Differential Effects of Oral Doxercalciferol (Hectorol®) or Paricalcitol (Zemplar®) in the Cyp27b1-Null Mouse Model of Uremia

Background/Aims: Kidney disease patients experience declining calcitriol levels and develop secondary hyperparathyroidism (SHPT). Animal models of uremia based on 5/6 nephrectomy (NTX) do not consistently reproduce this calcitriol deficiency. We developed an animal model, the NTX Cyp27b1-null mouse, which completely lacks endogenous calcitriol, and examined the suitability of this model for evaluation of treatment with vitamin D analogs in uremia. Methods: NTX was performed at 2 months of age. One week post-NTX, animals were treated for 4 weeks with vehicle; doxercalciferol at 30, 100 or 300 pg/g body weight (b.w.); or paricalcitol at 100, 300 or 1,000 pg/g b.w. by gavage 3 times per week. Results: Serum blood urea nitrogen and creatinine were elevated. Vehicle-treated NTX null mice had hypocalcemia and SHPT. Doxercalciferol at 100 or 300 pg/g b.w. normalized serum calcium and parathyroid hormone (PTH) levels. Paricalcitol at 300 or 1,000 pg/g normalized serum calcium, but PTH levels remained elevated. Osteomalacia was corrected by 100 pg/g b.w. of doxercalciferol or 1,000 pg/g b.w. of paricalcitol. The highest dose of doxercalciferol, but not of paricalcitol, significantly reduced osteitis fibrosa. Conclusion: Our results reveal the differential efficacy of doxercalciferol and paricalcitol in this novel animal model incorporating both calcitriol deficiency and renal insufficiency.     

Preclinical PK and PD Studies on 2��-O-Methyl-phosphorothioate RNA Antisense Oligonucleotides in the mdx Mouse Model

Antisense oligonucleotides (AONs) are being developed as RNA therapeutic molecules for Duchenne muscular dystrophy. For oligonucleotides with the 2′-O-methyl-phosphorothioate (2OMePS) RNA chemistry, proof of concept has been obtained in patient-specific muscle cell cultures, the mouse and dog disease models, and recently by local administration in Duchenne patients. To further explore the pharmacokinetic (PK)/pharmacodynamic (PD) properties of this chemical class of oligonucleotides, we performed a series of preclinical studies in mice. The results demonstrate that the levels of oligonucleotides in dystrophin-deficient muscle fibers are much higher than in healthy fibers, leading to higher exon-skipping levels. Oligonucleotide levels and half-life differed for specific muscle groups, with heart muscle showing the lowest levels but longest half-life (~46 days). Intravenous (i.v.), subcutaneous (s.c.), and intraperitoneal (i.p.) delivery methods were directly compared. For each method, exon-skipping and novel dystrophin expression were observed in all muscles, including arrector pili smooth muscle in skin biopsies. After i.v. administration, the oligonucleotide peak levels in plasma, liver, and kidney were higher than after s.c. or i.p. injections. However, as the bioavailability was similar, and the levels of oligonucleotide, exon-skipping, and dystrophin steadily accumulated overtime after s.c. administration, we selected this patient-convenient delivery method for future clinical study protocols.     

Lack of age-dependent development of the contingent negative variation (CNV) in migraine children?

Increased negativity of contingent negative variation (CNV) in adult migraineurs is thought to reflect cortical hyperexcitability. CNV amplitude changes with age in healthy adults. Recently, evidence emerged that this might not be the case for migraineurs. Our study investigates age-dependency of CNV during childhood age. Seventy-six healthy controls and 61 children with migraine without aura (IHS code 1.1) between 6 and 18 years were examined using an acoustic S1-S2-CNV-paradigm with a 3-s inter-stimulus interval. The amplitude of the late component of CNV, as well as total CNV at the vertex (Cz according to the international 10-20 system), were significantly higher in migraineurs without aura than in controls. Healthy controls showed increasing amplitudes of CNV with age, whereas in migraine children without aura amplitudes did not change. Thus group differences were reduced during adolescence. Increased CNV negativity might reflect a biological vulnerability to migraine, rather than being a result of chronification. Migraineurs seem to lack age-dependent development of CNV also during early age, which supports the hypothesis of migraine as a maturation disorder.     

Are Patients' Views on Seclusion Associated With Lack of Privacy in the Ward?

The lack of single-bed rooms in psychiatric wards may reduce the possibility of patients getting sufficient rest and privacy and may increase their risk of being overstimulated. This study explored whether residing in single- versus multiple-bed rooms in a psychiatric ward was associated with psychiatric patients' opinions about seclusion. More specifically, it was studied whether patients who had shared a room with other patients prior to seclusion rated seclusion more favorably. It was thought that they would rate seclusion more favorably due to the lack of rest they previously experienced in their regular room. For this, the Patient View-of-Seclusion Questionnaire of Hammill, McEvoy, Koral, and Schneider [Hammill, K., McEvoy, J., Koral, H., & Schneider, N. (1989). Hospitalized schizophrenic patient views about seclusion. Journal of Clinical Psychiatry, 50, 174-177] was completed by 54 secluded adult patients hospitalized in a locked ward of a Dutch psychiatric hospital. A significant association was found between residing in multiple-bed rooms prior to seclusion and a less negative view on seclusion. This finding suggests that the ward environment may have a rather large impact on how seclusion is perceived. The results underline the need for single-bed rooms in the treatment of psychiatric inpatients.