AAV-mediated gene transfer of a checkpoint inhibitor in combination with HER2-targeted CAR-NK cells as experimental therapy for glioblastoma.

Glioblastoma (GB) is the most common primary brain tumor, which is characterized by low immunogenicity of tumor cells and prevalent immunosuppression in the tumor microenvironment (TME). Targeted local combination immunotherapy is a promising strategy to overcome these obstacles. Here, we evaluated tumor-cell specific delivery of an anti-PD-1 immunoadhesin (aPD-1) via a targeted adeno-associated viral vector (AAV) as well as HER2-specific NK-92/5.28.z (anti-HER2.CAR/NK-92) cells as components for a combination immunotherapy. In co-culture experiments, target-activated anti-HER2.CAR/NK-92 cells modified surrounding tumor cells and bystander immune cells by triggering the release of inflammatory cytokines and upregulation of PD-L1. Tumor cell-specific delivery of aPD-1 was achieved by displaying a HER2-specific designed ankyrin repeat protein (DARPin) on the AAV surface. HER2-AAV mediated gene transfer into GB cells correlated with HER2 expression levels, without inducing anti-viral responses in transduced cells. Furthermore, AAV-transduction did not interfere with anti-HER2.CAR/NK-92 cell-mediated tumor cell lysis. After selective transduction of HER2+ cells, aPD-1 expression was detected at the mRNA and protein level. The aPD-1 immunoadhesin was secreted in a time-dependent manner, bound its target on PD-1-expressing cells and was able to re-activate T cells by efficiently disrupting the PD-1/PD-L1 axis. Moreover, high intratumoral and low systemic aPD-1 concentrations were achieved following local injection of HER2-AAV into orthotopic tumor grafts in vivo. aPD-1 was selectively produced in tumor tissue and could be detected up to 10 days after a single HER2-AAV injection. In subcutaneous GL261-HER2 and Tu2449-HER2 immunocompetent mouse models, administration of the combination therapy significantly prolonged survival, including complete tumor control in several animals in the GL261-HER2 model. In summary, local therapy with aPD-1 encoding HER2-AAVs in combination with anti-HER2.CAR/NK-92 cells may be a promising novel strategy for GB immunotherapy with the potential to enhance efficacy and reduce systemic side effects of immune-checkpoint inhibitors.

[Complication management following resection and reconstruction of the upper limbs and shoulder girdle]. / Komplikationsmanagement nach Tumorresektion und Defektrekonstruktion an der oberen Extremität und am Schultergürtel.

BACKGROUND: Sarcomas of the upper limbs commonly affect the proximal humerus or scapula. Complications after tumor resection and reconstruction are rare but cannot be neglected, particularly after tumor endoprosthetic reconstructions. MATERIALS AND METHODS: The most common complications after resection of sarcomas of the upper limbs and shoulder girdle are described, and current knowledge regarding complication management is presented. Additionally, a selective literature search was performed, incorporating personal experiences. RESULTS: Wound healing disorders and infections after tumor resection without specific reconstruction (clavicle resection, scapulectomy) usually respond well to conservative or surgical treatment. However, periprosthetic infections after reconstruction using a megaendoprosthesis constitute a severe and frequent complication, with an incidence of 5-10%. Two-stage implant replacement still represents the gold standard, although in selected cases, one-stage revision with retention of the prosthetic stem appears warranted. Secondary amputation as a result of periprosthetic infection is rare compared to the situation with infections of the lower limb. Mechanical complications necessitating surgical revision are mostly limited to joint dislocation after inverse total shoulder replacement (TSR). (Sub)luxation in anatomic TSR can be tolerated provided there is no tendency toward perforation of the skin in a asymptomatic patient. Biological reconstructions are most often indicated for reconstruction of intercalary defects of the humerus, and revision is necessitated most frequently by mechanical complications. Despite multiple surgical revisions, stable reconstructions and limb salvage can usually be achieved in the upper limb.

What is the Likelihood That Tumor Endoprostheses Will Experience a Second Complication After First Revision in Patients With Primary Malignant Bone Tumors And What Are Potential Risk Factors?

BACKGROUND: Endoprosthetic reconstruction of massive bone defects has become the reconstruction method of choice after limb-sparing resection of primary malignant tumors of the long bones. Given the improved survival rates of patients with extremity bone sarcomas, an increasing number of patients survive but have prosthetic complications over time. Several studies have reported on the outcome of first endoprosthetic complications. However, no comprehensive data, to our knowledge, are available on the likelihood of an additional complication and the associated risk factors, despite the impact of this issue on the affected patients. QUESTIONS/PURPOSES: (1) What are the types and timing of complications and the implant survivorship free from revision after the first complication? (2) Does survivorship free from repeat revision for a second complication differ by anatomic sites? (3) Is the type of first complication associated with the risk or the type of a second complication? (4) Are patient-, tumor-, and treatment-related factors associated with a higher likelihood of repeat revision? METHODS: Between 1993 and 2015, 817 patients underwent megaprosthetic reconstruction after resection of a tumor in the long bones with a single design of a megaprosthetic system. No other prosthetic system was used during the study period. Of those, 75% (616 of 817) had a bone sarcoma. Seventeen patients (3%) had a follow-up of less than 6 months, 4.5% (27 of 599) died with the implant intact before 6 months and 43% (260 of 599 patients) underwent revision. Forty-three percent of patients (260 of 599) experienced a first prosthetic complication during the follow-up period. Ten percent of patients (26 of 260) underwent amputation after the first complication and were excluded from further analysis. Second complications were classified using the classification of Henderson et al. to categorize surgical results. Briefly, this system categorizes complications as wound dehiscence (Type 1); aseptic loosening (Type 2); implant fractures or breakage and periprosthetic fracture (Type 3); infection (Type 4); and tumor progression (Type 5). Implant survival curves were calculated with the Kaplan-Meier method and compared using the log-rank test. Hazard ratios (HR) were estimated with their respective 95% CIs in multivariate Cox regression models. RESULTS: A second complication occurred in 49% of patients (115 of 234) after a median of 17 months (interquartile range [IQR] 5 to 48) after the surgery for the first complication. The time to complication did not differ between the first (median 16 months; IQR 5 to 57) and second complication (median 17 months; IQR 5 to 48; p = 0.976). The implant survivorship free from revision surgery for a second complication was 69% (95% CI 63 to 76) at 2 years and 46% (95% CI 38 to 53) at 5 years. The most common mode of second complication was infection 39% (45 of 115), followed by structural complications with 35% (40 of 115). Total bone and total knee reconstructions had a reduced survivorship free from revision surgery for a second complication at 5 years (HR 2.072 [95% CI 1.066 to 3.856]; p = 0.031) compared with single joint replacements. With the numbers we had, we could not show a difference between the survivorship free of revision for a second complication based on the type of the first complication (HR 0.74 [95% CI 0.215 to 2.546]; p = 0.535). We did not detect an association between total reconstruction length, patient BMI, and patient age and survivorship free from revision for a second complication. Patients had a higher risk of second complications after postoperative radiotherapy (HR 1.849 [95% CI 1.092 to 3.132]; p = 0.022) but not after preoperative radiotherapy (HR 1.174 [95% CI 0.505 to 2.728]; p = 0.709). Patients with diabetes at the time of initial surgery had a reduced survivorship free from revision for a second complication (HR 4.868 [95% CI 1.497 to 15.823]; p = 0.009). CONCLUSIONS: Patients who undergo revision to treat a first megaprosthetic complication must be counseled regarding the high risk of future complications. With second complications occurring relatively soon after the first revision, regular orthopaedic follow-up visits are advised. Preoperative rather than postoperative radiotherapy should be performed when possible. Future studies should evaluate the effectiveness of different approaches in treating complications considering implant survivorship free of revision for a second complication. LEVEL OF EVIDENCE: Level III, therapeutic study.

Charge states and lattice sites of dilute implanted Sn in ZnO.

The common charge states of Sn are 2+ and 4+. While charge neutrality considerations favour 2+ to be the natural charge state of Sn in ZnO, there are several reports suggesting the 4+ state instead. In order to investigate the charge states, lattice sites, and the effect of the ion implantation process of dilute Sn atoms in ZnO, we have performed 119Sn emission Mössbauer spectroscopy on ZnO single crystal samples following ion implantation of radioactive 119In (T ½ = 2.4 min) at temperatures between 96 K and 762 K. Complementary perturbed angular correlation measurements on 111mCd implanted ZnO were also conducted. Our results show that the 2+ state is the natural charge state for Sn in defect free ZnO and that the 4+ charge state is stabilized by acceptor defects created in the implantation process.

Serum proteomic test in advanced non-squamous non-small cell lung cancer treated in first line with standard chemotherapy.

BACKGROUND: VeriStrat is a blood-based proteomic test with predictive and prognostic significance in second-line treatments for non-small cell lung cancer (NSCLC). This trial was designed to investigate the role of VeriStrat in first-line treatment of advanced NSCLC with standard chemotherapy. Here we present the results for 76 non-squamous patients treated with a combination of carboplatin or cisplatin with pemetrexed. METHODS: The test-assigned classifications of VeriStrat Good or VeriStrat Poor to samples collected at baseline. The primary end point was progression-free survival (PFS); secondary end points included overall survival (OS) and objective response. Exploratory analyses of end points separately in carboplatin/pemetrexed and cisplatin/pemetrexed subgroups were also conducted. RESULTS: Patients classified as VeriStrat Good had longer PFS and OS than VeriStrat Poor: 6.5 vs 1.6 months and 10.8 vs 3.4 months, respectively; the corresponding hazard ratios (HRs) were 0.36 (P<0.0001) and 0.26 (P<0.0001); they were also more likely to achieve objective response. Prognostic significance of VeriStrat was confirmed in multivariate analysis. Significant differences in OS and PFS between Veristrat classifications were also found when treatment subgroups were analysed separately. CONCLUSIONS: The trial demonstrated clinical utility of VeriStrat as a prognostic test for standard first-line chemotherapy of non-squamous advanced NSCLC.

[Morbidity, mortality and analysis of prognostic factors for colorectal cancer]. / Morbidität, Mortalität und Analyse prognostischer Faktoren beim kolorektalen Karzinom.

BACKGROUND: This study analyzed morbidity, mortality and prognostic factors for patient survival in a single center collective of patients with colorectal cancer and a high follow-up rate. MATERIAL AND METHODS: A total of 698 consecutive patients were included in this study. Data were collected prospectively. Descriptive and survival analyses as well as Cox regression analyses were performed to identify factors for morbidity, mortality and prognostic factors for survival. RESULTS: At presentation 78.8 % of the colon cancer patients and 83.5 % of rectal cancer patients showed symptomatic disease and 6.5 % of patients underwent an emergency procedure. Mortality was 3.6 %, morbidity was 42.7 % and 4.3 % of patients developed an anastomotic leakage with the need of reoperation. In spite of the regular application of a fast-track program, 10 % of patients had a prolonged duration of bowel paralysis. In patients with colon cancer there were no differences between overall survival (OAS) and disease-free survival, whereas there was a significant difference in patients with rectal cancer. The mean survival of all patients was 65.39 ± 1.722 months. The ASA score, cardiovascular disease, number of metastatic lymph nodes, lymph node ratio, residual tumor and general or surgery-associated complications were strongly independent influencing factors on OAS. A Cox analysis revealed age at diagnosis and microscopic residual tumor (TNM R1) as highly significant influencing factors on OAS. Other significant factors of influence on OAS were development of general or surgery-associated complications and the presence of cardiovascular diseases. CONCLUSION: Cardiovascular disease leads to a higher morbidity rate whereas age, International Union Against Cancer (UICC) stage, R-status, lymphatic spread and occurrence of complications are important prognostic factors for survival.

The mechanically induced structural disorder in barium hexaferrite, BaFe12O19, and its impact on magnetism.

The response of the structure of the M-type barium hexaferrite (BaFe12O19) to mechanical action through high-energy milling and its impact on the magnetic behaviour of the ferrite are investigated. Due to the ability of the (57)Fe Mössbauer spectroscopic technique to probe the environment of the Fe nuclei, a valuable insight on a local atomic scale into the mechanically induced changes in the hexagonal structure of the material is obtained. It is revealed that the milling of BaFe12O19 results in the deformation of its constituent polyhedra (FeO6 octahedra, FeO4 tetrahedra and FeO5 triangular bi-pyramids) as well as in the mechanically triggered transition of the Fe(3+) cations from the regular 12k octahedral sites into the interstitial positions provided by the magnetoplumbite structure. The response of the hexaferrite to the mechanical treatment is found to be accompanied by the formation of a non-uniform nanostructure consisting of an ordered crystallite surrounded/separated by a structurally disordered surface shell/interface region. The distorted polyhedra and the non-equilibrium cation distribution are found to be confined to the amorphous near-surface layers of the ferrite nanoparticles with the thickness extending up to about 2 nm. The information on the mechanically induced short-range structural disorder in BaFe12O19 is complemented by an investigation of its magnetic behaviour on a macroscopic scale. It is demonstrated that the milled ferrite nanoparticles exhibit a pure superparamagnetism at room temperature. As a consequence of the far-from-equilibrium structural disorder in the surface shell of the nanoparticles, the mechanically treated BaFe12O19 exhibits a reduced magnetization and an enhanced coercivity.

Attenuation of mania-like behavior in Na(+),K(+)-ATPase α3 mutant mice by prospective therapies for bipolar disorder: melatonin and exercise.

Bipolar disorder is a neuropsychiatric disease characterized by states of mania with or without depression. Pharmacological treatments can be inadequate at regulating mood for many individuals. Melatonin therapy and aerobic exercise are independent prospective therapies for bipolar disorder that have shown potential as mood stabilizers in humans. Myshkin mice (Myk/+) carry a heterozygous missense mutation in the neuronal Na(+),K(+)-ATPase α3 and model mania-related symptoms of bipolar disorder including increased activity, risk-taking behavior and reductions in sleep. One cohort of Myk/+ and wild-type littermates (+/+) was treated with melatonin and a separate cohort was treated with voluntary exercise. Mania-related behavior was assessed in both cohorts. The effect of melatonin on sleep and the effect of exercise on brain-derived neurotrophic factor (BDNF) expression in the hippocampus were assayed. Melatonin and voluntary wheel running were both effective at reducing mania-related behavior in Myk/+ but did not affect behavior in +/+. Melatonin increased sleep in Myk/+ and did not change sleep in +/+. Myk/+ showed higher baseline levels of BDNF protein in the hippocampus than +/+. Exercise increased BDNF protein in +/+ hippocampus, while it did not significantly affect BDNF levels in Myk/+ hippocampus. These findings support initial studies in humans indicating that melatonin and exercise are useful independent adjunct therapies for bipolar disorder. Their effects on mood regulation should be further examined in randomized clinical trials. Our results also suggest that hippocampal BDNF may not mediate the effects of exercise on mania-related behavior in the Myk/+ model of mania.

VeriStrat(®) has prognostic value in advanced stage NSCLC patients treated with erlotinib and sorafenib.

BACKGROUND: The serum proteomic test VeriStrat has been shown to be able to classify advanced non-small cell lung cancer (NSCLC) patients for overall survival (OS) after treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). In this study, VeriStrat was evaluated as a pre-treatment stratification tool in patients with advanced stage NSCLC for treatment with the combination of erlotinib and sorafenib, considering both OS and progression-free survival (PFS) as end points. METHODS: Serum samples from 50 patients treated within the context of a phase II trial of first-line erlotinib and sorafenib were analysed with VeriStrat, a fully locked mass spectrometry-based test that identifies patients likely to have good or poor outcome on EGFR therapy based on eight distinct features in mass spectra. Analysis was performed fully blinded to all clinical data, and then the outcome data were analysed with respect to the obtained serum classifications. RESULTS: VeriStrat classified pre-treatment samples into two groups, VeriStrat Good and VeriStrat Poor, which were significantly different in OS (hazard ratio (HR) 0.30, log-rank P=0.009) and in PFS (HR 0.40, log-rank P=0.035). CONCLUSION: VeriStrat has shown its potential for stratification of unselected, advanced stage NSCLC patients treated in first line with a combination of erlotinib and sorafenib.

[Surgery of gastric cancer in a medium volume center]. / Chirurgie des Magenkarzinoms in einer Schwerpunktklinik.

BACKGROUND: The aim of the study was to evaluate prognostic factors for the surgical treatment of gastric cancer in a medium volume center. The investigation focused in particular on morbidity and mortality. PATIENTS AND METHODS: From January 2005 to August 2011 a total of 74 patients with gastric cancer were surgically treated in our medium volume center. The study of these patients included morbidity, mortality, UICC (International Union Against Cancer) stage, Laurén classification, surgical therapy procedure, American Society of Anesthesiologists (ASA) classification and duration of surgery. RESULTS: After surgery 11 patients suffered from complications with a morbidity of 14.9% and a mortality of 1.4% (n=1). No significant differences could be detected during the study period. CONCLUSION: In comparison to other studies the morbidity and mortality rates signify similar to better data than complications of high volume centers which might be due to the small group of surgeons who are specialized in gastric surgery.

Genetic suppression of agrin reduces mania-like behavior in Na+ , K+ -ATPase α3 mutant mice.

Myshkin mice heterozygous for an inactivating mutation in the neuron-specific Na(+) ,K(+) -ATPase α3 isoform show behavior analogous to mania, including an abnormal endogenous circadian period. Agrin is a proteoglycan implicated as a regulator of synapses that has been proposed to inhibit activity of Na(+) ,K(+) -ATPase α3. We examined whether the mania-related behavior of Myshkin mice could be rescued by a reduction in the expression of agrin through genetic knockout. The suppression of agrin reduced hyperambulation and holeboard exploration, restored anxiety-like behavior (or reduced risk-taking behavior), improved prepulse inhibition and shortened the circadian period. Hence, agrin is important for regulating mania-like behavior and circadian rhythms. In Myshkin mice, the suppression of agrin increased brain Na(+) ,K(+) -ATPase activity by 11 ± 4%, whereas no effect on Na(+) ,K(+) -ATPase activity was detected when agrin was suppressed in mice without the Myshkin mutation. These results introduce agrin as a potential therapeutic target for the treatment of mania and other neurological disorders associated with reduced Na(+) ,K(+) -ATPase activity and neuronal hyperexcitability.

Impaired social memories in 129P2 inbred mice are rescued by reduced Csk expression.

The C-terminal Src kinase (Csk) is an essential signaling factor guiding central nervous system (CNS) development. In the adult brain, Csk-mediated control of Src may also modulate glutamatergic synaptic transmission and N-methyl-d-aspartate receptor (NMDAR)-dependent synaptic plasticity. The regulation of N-methyl-d-aspartate (NMDA)-dependent plasticity by a myriad of kinase cascades has been investigated intensively during spatial and fear learning, while little is known about the regulatory kinases and role of NMDA-dependent plasticity during equally critical forms of social learning. We assessed social memory in Csk(+/+) and Csk(+/-) mice backcrossed onto 129P2, an inbred strain with wild-type impairments in social memory. Reduced Csk expression in Csk(+/-) mice was associated with increased NMDAR subunit 2B (NR2B) phosphorylation in the amygdala (AM) and olfactory bulb (OB), and with markedly improved social recognition memory and social transmission of food preference (STFP). In contrast, phosphorylation of NR2B was only slightly increased in the hippocampus of 129P2/Csk(+/-) mice, and the poor spatial object recognition memory of wild-type 129P2/Csk(+/+) mice was not rescued by reduced Csk expression. The Csk pathway appears to be a critical signaling cascade regulating social learning and memory, and presents a possible therapeutic target in diseases such as autism that are characterized by aberrant social behaviors.

[Pediatric appendicitis : Open or laparoscopic appendicectomy in a specialized visceral surgical clinic?]. / Kindliche Appendizitis : Offene oder laparoskopische Appendektomie in einer viszeralchirurgischen Schwerpunktklinik?

Following the first description of open appendicectomy using a lateral incision in the right lower abdomen by McBurney in 1894, this intervention was considered to be the standard method for treatment of appendicitis for nearly 100 years. In 1983 the gynecologist Semm presented a new option for the surgical therapy of appendicitis with the implementation of laparoscopic appendicectomy. Since then the indications for laparoscopic therapy have developed from young adults through elderly patients to children, pregnant women and finally to infants and newborns.

Decreased neuronal Na+, K+ -ATPase activity in Atp1a3 heterozygous mice increases susceptibility to depression-like endophenotypes by chronic variable stress.

Unipolar depression and bipolar depression are prevalent and debilitating diseases in need of effective novel treatments. It is becoming increasingly evident that depressive disorders manifest from a combination of inherited susceptibility genes and environmental stress. Genetic mutations resulting in decreased neuronal Na(+) ,K(+) -ATPase (sodium-potassium adenosine triphosphatase) activity may put individuals at risk for depression given that decreased Na(+) ,K(+) -ATPase activity is observed in depressive disorders and animal models of depression. Here, we show that Na(+) ,K(+) -ATPase α3 heterozygous mice (Atp1a3(+/-) ), with 15% reduced neuronal Na(+) ,K(+) -ATPase activity, are vulnerable to develop increased depression-like endophenotypes in a chronic variable stress (CVS) paradigm compared to wild-type littermates (Atp1a3(+/+) ). In Atp1a3(+/+) mice CVS did not decrease Na(+) ,K(+) -ATPase activity, however led to despair-like behavior in the tail suspension test (TST), anhedonia in a sucrose preference test and a minimal decrease in sociability, whereas in Atp1a3(+/-) mice CVS decreased neuronal Na(+) ,K(+) -ATPase activity to 33% of wild-type levels, induced despair-like behavior in the TST, anhedonia in a sucrose preference test, anxiety in the elevated plus maze, a memory deficit in a novel object recognition task and sociability deficits in a social interaction test. We found that a mutation that decreases neuronal Na(+) ,K(+) -ATPase activity interacts with stress to exacerbate depression. Furthermore, we observed an interesting correlation between Na(+) ,K(+) -ATPase activity and mood that may relate to both unipolar depression and bipolar disorder. Pharmaceuticals that increase Na(+) ,K(+) -ATPase activity or block endogenous Na(+) , K(+) -ATPase inhibition may provide effective treatment for depressive disorders and preclude depression in susceptible individuals.

[Rectal impalement with rupture of the small intestine]. / Transrektale Pfählungsverletzung mit Dünndarmruptur.

We report the case of a 44-year-old farmer who fell from a ladder onto the handle of a wheelbarrow and sustained a rectal impalement with rupture of the small intestine. After the clinical diagnostics an emergency laparotomy was carried out with primary suturing of the rectal perforation. Furthermore there were two perforations of the small intestine which were treated with an ileostomy. The replacement of the ileostomy was carried out after 7 weeks.

Enhanced dopamine function in DISC1-L100P mutant mice: implications for schizophrenia.

Significant advances have been made in understanding the role of disrupted-in-schizophrenia-1 (DISC1) in the brain and accumulating findings suggest the possible implication of DISC1 in the regulation of dopamine (DA) function. A mutation in the second exon of DISC1 at L100P leads to the development of schizophrenia-related behavior in mutant mice (DISC1-L100P). We investigated here the role of DA in the expression of schizophrenia-related endophenotypes in the DISC1-L100P genetic mouse model. The mutated DISC1 resulted in facilitation of the psychostimulant effect of amphetamine in DISC1-L100P mutant mice assessed in the open field and prepulse inhibition (PPI) tests. Biochemical studies detected a 2.1-fold increase in the proportion of striatal D receptors without significant changes in DA release in vivo in the striatum of DISC1-L100P mutants in response to the low dose of amphetamine. The D(2) receptor antagonist haloperidol reversed the hyperactivity, PPI and latent inhibition (LI) deficits and blocked the psychostimulant effect of amphetamine in DISC1-L100P mutants. Taken together, our findings show the role of DISC1 in D(2) -related pathophysiological mechanism of schizophrenia, linking DISC1 with well-established DA hypothesis of schizophrenia.

Genetic loss of D-amino acid oxidase activity reverses schizophrenia-like phenotypes in mice.

Reduced function of the N-methyl-d-aspartate receptor (NMDAR) has been implicated in the pathophysiology of schizophrenia. The NMDAR contains a glycine binding site in its NR1 subunit that may be a useful target for the treatment of schizophrenia. In this study, we assessed the therapeutic potential of long-term increases in the brain levels of the endogenous NMDAR glycine site agonist D-serine, through the genetic inactivation of its catabolic enzyme D-amino acid oxidase (DAO) in mice. The effects of eliminating DAO function were investigated in mice that display schizophrenia-related behavioral deficits due to a mutation (Grin 1(D481N)) in the NR1 subunit that results in a reduction in NMDAR glycine affinity. Grin 1(D481N) mice show deficits in sociability, prolonged latent inhibition, enhanced startle reactivity and impaired spatial memory. The hypofunctional Dao 1(G181R) mutation elevated brain levels of D-serine, but alone it did not affect performance in the behavioral measures. Compared to animals with only the Grin 1(D481N) mutation, mice with both the Dao1(G181R) and Grin 1(D481N) mutations displayed an improvement in social approach and spatial memory retention, as well as a reversal of abnormally persistent latent inhibition and a partial normalization of startle responses. Thus, an increased level of D-serine resulting from decreased catalysis corrected the performance of mice with deficient NMDAR glycine site activation in behavioral tasks relevant to the negative and cognitive symptoms of schizophrenia. Diminished DAO activity and elevations in D-serine may serve as an effective therapeutic intervention for the treatment of psychiatric symptoms.