The prevalence rates of motor symptoms in schizophrenia are surpr

The prevalence rates of motor symptoms in schizophrenia are surprisingly high, and recent studies indicate a possible pathobiology. In particular, the development and maturation of the human motor system appears to be closely linked to the emergence of motor symptoms observed in schizophrenia. Post-mortem and neuroimaging results demonstrated aberrant structure and function of premotor and motor cortices, basal ganglia, thalamus, and the connecting white matter tracts. Animal models have focused

on aberrant neurotransmission and genetic contributions. Findings of localized abnormal oligodendrocyte function and myelination point to the special role of the white matter in schizophrenia, and recent Verubecestat ic50 studies specifically found an association between motor abnormalities and white matter structure in schizophrenia. This review of the literature supports the idea that motor symptoms are closely related to the neurodevelopmental disturbances of schizophrenia and a distinct syndromal dimension with its own pathophysiology. Copyright (c) 2012 S. Karger AG, Basel”
“Introduction: Previous studies have evaluated the effect of modafinil on residual NU7441 supplier excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea syndrome (OSAS)

under effective CPAP treatment. Even though those trials also used placebo groups, we suppose that the placebo effect might influence the patients’ response to modafinil.

Methods: Twenty sleepy patients with OSAS under CPAP treatment were selected. All of them had Epworth Sleepiness Scale (ESS) > 10. Following baseline evaluation (T1), all subjects were instructed to take placebo for 7 days. After this single-blind placebo phase and second evaluation (T2), patients were randomly allocated to placebo or modafinil treatment for 21 days in a double-blind protocol. Patients underwent a final evaluation (T3) on the last day of drug intake. The evaluations

at T1, T2 and T3 consisted of. medical and laboratory examinations, nocturnal polysomnography, ESS, maintenance of wakefulness test (MWT) and complex reaction time (CRT-NY). buy PS-341 In addition, in T2 and T3 the change of illness severity scale (CGI-C) and the evaluation of quality of life. (SF-36) were applied.

Results: The comparison between the two groups during the three periods studied, showed the following results: in the modafinil group, ESS score did not change during the initial placebo period, but there was a significant reduction during the modafinil treatment period (p=0.0006); in the placebo group a significant reduction occurred during the initial placebo period (p=0.05), and no further change was observed in the treatment (placebo) period. A significant difference was found between the two groups after the placebo period (T2) (p=0.02). Three patients (33%) of the modafinil group and 9 patients (81%) of the placebo group were classified as placebo-responsive (X-2 : p=0.


“Development of a vaccine for the common cold has been thw


“Development of a vaccine for the common cold has been thwarted by the fact that there are more than 100 serotypes of human rhinovirus (HRV). We

GDC-0994 clinical trial previously demonstrated that the HRV14 capsid is dynamic and transiently displays the buried N termini of viral protein 1 (VP1) and VP4. Here, further evidence for this “”breathing”" phenomenon is presented, using antibodies to several peptides representing the N terminus of VP4. The antibodies form stable complexes with intact HRV14 virions and neutralize infectivity. Since this region of VP4 is highly conserved among all of the rhinoviruses, antiviral activity by these anti-VP4 antibodies is cross-serotypic. The antibodies inhibit HRV16 infectivity in a temperature- and time-dependent manner consistent with the breathing behavior. Monoclonal and polyclonal antibodies raised against the 30-residue peptide do not react with peptides shorter than 24 residues, suggesting that these peptides are adopting three-dimensional conformations that are highly dependent upon the length of the peptide. Furthermore, there is evidence www.selleckchem.com/products/apo866-fk866.html that the N termini of VP4 are interacting with each other upon extrusion from the capsid. A Ser5Cys mutation in VP4 yields an infectious virus that forms cysteine cross-links in VP4 when the virus is incubated at room temperature but not at 4 degrees C. The fact that all of the VP4s are involved in this cross-linking

process strongly suggests that VP4 forms specific oligomers upon extrusion. Together these results suggest that it may be possible to develop a pan-serotypic

peptide vaccine to HRV, but its design will likely require details about see more the oligomeric structure of the exposed termini.”
“Corballis [Corballis, M. C. (2009). Comparing a single case with a control sample: Refinements and extensions. Neuropsychologia] offers an interesting position paper on statistical inference in single-case studies. The following points arise: (1) Testing whether we can reject the null hypothesis that a patient’s score is an observation from the population of control scores can be a legitimate aim for single-case researchers, not just clinicians. (2) Counter to the claim made by Corballis [Corballis, M. C. (2009). Comparing a single case with a control sample: Refinements and extensions. Neuropsychologia], Crawford and Howell’s [Crawford, J. R., & Howell, D. C. (1998). Comparing an individual's test score against norms derived from small samples. The Clinical Neuropsychologist, 12, 482-486] method does test whether we can reject the above null hypothesis. (3) In all but the most unusual of circumstances Crawford and Howell’s method can also safely be used to test whether the mean of a notional patient population is lower than that of a control population, should neuropsychologists wish to construe the test in this way.

Moreover, we also revealed that this activation of ERK1/2 occurre

Moreover, we also revealed that this activation of ERK1/2 occurred through transient receptor potential (TRP) A1, a member of the TRP family of ion channels. In contrast, it is known that the activation of p38 MAPK (p38) contributes to the development and maintenance of inflammatory and neuropathic pain. On the basis of these results, the aim of this study was to investigate the involvement of p38 and TRPA1 in acute visceral pain. Male Sprague-Dawley rats were used.

Electromyographic responses to gastric distension (GD) were recorded from the acromiotrapezius muscle. We then examined the phosphorylated-p38 (p-p38) labeling in the dorsal root ganglion (DRG) after GD using immunohistochemistry. Selleck LY2835219 Noxious GD induced p-p38 in DRG neurons with a peak at 2 min after GD. We also found a stimulus intensity-dependent increase in the number of p-p38-immunoreactive neurons in the DRG. Intrathecal administration of the p38 inhibitor, SB203580, attenuated the electromyographic response to noxious GD. Furthermore, intrathecal administration of TRPA1 antisense oligodeoxynucleotide decreased the p38 activation in DRG neurons. The activation of p38 pathways in DRG neurons by noxious GD may be correlated with the activation state of the primary afferent neurons through TRPA1, and further, involved in the development of visceral

pain. NeuroReport 24:68-72 (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins. NeuroReport 2013, 24:68-72″
“Improved survival of patients with acute SRT1720 mw lymphoblastic leukemia (ALL) has emerged from identifying new prognostic markers; however, 20% of children still suffer recurrence. Previously, the altered expression of Fat1 cadherin has been implicated in a number of solid tumors. In this report, in vitro analysis shows

that Fat1 protein is expressed by a range of leukemia cell lines, but not by normal peripheral blood (PB) and bone marrow (BM) cells from healthy donors. In silico analysis of expression of array data from clinical leukemias found significant levels of Fat1 transcript in 11% of acute myeloid AZD5582 solubility dmso leukemia, 29% and 63% of ALL of B and T lineages, respectively, and little or no transcript present in normal PB or BM. Furthermore, in two independent studies of matched diagnosis – relapse of precursor B-cell (preB) ALL pediatric samples (n = 32 and n = 27), the level of Fat1 mRNA expression was prognostic at the time of diagnosis. High Fat1 mRNA expression was predictive of shorter relapse-free and overall survival, independent of other traditional prognostic markers, including white blood cell count, sex and age. The data presented demonstrate that Fat1 expression in preB-ALL has a role in the emergence of relapse and could provide a suitable therapeutic target in high-risk preB-ALL.

(J Thorac Cardiovasc Surg 2012; 144:1307-14)”
“Reflux venous

(J Thorac Cardiovasc Surg 2012; 144:1307-14)”
“Reflux venous signal on the brain and neck time-of-flight magnetic resonance angiography (TOF MRA) is thought to be related AZD7762 supplier to a compressed left brachiocephalic vein. This study is aimed to assess the prevalence of venous reflux flow in internal jugular vein (IJV),

sigmoid sinus/transverse sinus (SS/TS), and inferior petrosal sinus (IPS) on the brain and neck TOF MRA and its pattern.

From the radiology database, 3,475 patients (1,526 men, 1,949 women, age range 19-94, median age 62 years) with brain and neck standard 3D TOF MRA at 3 T and 1.5 T were identified. Rotational maximal intensity projection images of 3D TOF MRA were assessed for the presence of reflux flow in IJV, IPS, and SS/TS.

Fifty-five patients (1.6 %) had reflux flow, all in the left side. It was more prevalent in females (n = 43/1,949, 2.2 %) than in males (n = 12/1,526, 0.8 %) (p = 0.001). The mean age of patients with reflux flow (66 years old) was older than those (60 years old) without reflux flow

(p = 0.001). Three patients Rigosertib in vivo had arteriovenous shunt in the left arm for hemodialysis. Of the remaining 52 patients, reflux was seen on IJV in 35 patients (67.3 %). There were more patients with reflux flow seen on SS/TS (n = 34) than on IPS (n = 25).

Venous reflux flow on TOF MRA is infrequently observed, and reflux pattern is variable. Because it is exclusively located in the left side, the reflux signal on TOF MRA could be an alarm for an undesirable candidate for a contrast injection on the

left side for contrast-enhanced imaging study.”
“The level of F-2-isoprostanes (F-2-IsoP) in blood or urine is widely regarded as the reference marker for the assessment of oxidative stress. As a result, nowadays, F-2-IsoP is the most frequently measured oxidative stress marker. Nevertheless, determining F-2-IsoP is a challenging task and the measurement is neither free of mishaps nor straightforward. This review presents for the first time the effect of acute and chronic exercise on F-2-IsoP levels in plasma, urine and skeletal muscle, placing emphasis on the origin, the methodological caveats and the interpretation either of F-2-IsoP alterations. From data analysis, the following effects of exercise have emerged: (i) acute exercise dearly increases F-2-IsoP levels in plasma and this effect is generally short-lived. (ii) acute exercise and increased contractile activity markedly increase F-2-IsoP levels in skeletal muscle, (iii) chronic exercise exhibits trend for decreased F-2-IsoP levels in urine but further research is needed. Theoretically, it seems that significant amounts of F-2-IsoP can be produced not only from phospholipids but from neutral lipids as well.

The absence of lamin A (i) caused clustering of pU(L)34 in the nu

The absence of lamin A (i) caused clustering of pU(L)34 in the nuclear rim of cells infected with wild-type virus,

(ii) produced extensions of the INM bearing pUL34 protein in cells infected with a U(s)3 kinase-dead mutant, (iii) precluded accumulation of virions in the Cl-amidine chemical structure perinuclear space of cells infected with this mutant, and (iv) partially restored replication of this virus. The latter observation suggests that lamin A normally impedes viral infectivity and that U(s)3 kinase activity partially alleviates this impediment. On the other hand, lamin B1 is necessary for optimal viral replication, probably through its well-documented effects on many cellular pathways. Finally, neither lamin A nor B1 was absolutely required for targeting pU(L)34 to the INM, suggesting that this targeting is mediated by redundant functions or can be mediated by other proteins.”
“OBJECTIVE: Intracranial subdural grid monitoring is a useful diagnostic technique for surgical localization in patients with intractable partial epilepsy. The rationale click here for the present study was to assess the morbidity of intracranial recordings and the surgical outcomes.

METHODS: We retrospectively reviewed the clinical data for 189 unique

patients undergoing 198 intracranial subdural grid monitoring sessions between 1996 and 2004 at a tertiary epilepsy center.

RESULTS: The mean age of patients undergoing monitoring was 28 +/- 14 years. An average of 63 +/- 23 electrodes were inserted. C188-9 The mean duration of monitoring was 8 +/- 4 days. Localization of an epileptogenic zone occurred in 156 sessions (79%) resulting in 136 resections (69%). There were 13 major complications (6.6%), including five infections and six hematomas. Three patients (1.5%) developed permanent deficits related to implantation. Sixty-two (47%) of 136 patients undergoing resection were seizure-free after resection. An additional 38 patients

(28%) had a significant reduction in seizures. The mean follow-up was 51 +/- 30 months. The duration of monitoring, bone flap replacement, number of electrodes, and perioperative corticosteroids were not associated with infection or complication.

CONCLUSION: Subdural grid monitoring for identification an epileptogenic focus is high yield, revealing a focus in 79% of monitoring sessions. Complications rarely result in permanent morbidity (1.5%). Surgical outcome indicated that 74% of patients experienced a favorable reduction in seizure tendency.”
“Triggering uncontrolled cellular proliferation, chronic inflammation, and/or disruption of p53 activity is critical for tumorigenesis initiated by latent viral oncogenes. The adenovirus type 5 (Ad5) early genes E1A and E1B can maintain lifelong latency in the lungs of patients with chronic pulmonary diseases.

The study period

was between January 1, 2000, and Decembe

The study period

was between January 1, 2000, and December 31, 2004. We assessed associations between measures of use of health care services and body-mass index (BMI, defined as the selleck screening library weight in kilograms divided by the square of the height in meters) before pregnancy or in early pregnancy. The women were categorized as underweight (BMI <18.5), normal (BMI 18.5 to 24.9), overweight (BMI 25.0 to 29.9), obese (BMI 30.0 to 34.9), very obese (BMI 35.0 to 39.9), or extremely obese (BMI greater/equal 40.0). The primary outcome was the mean length of hospital stay for delivery.

Results: After adjustment for age, race or ethnic group, level of education, and parity, the mean (+/-SE) length of hospital stay for PERK inhibitor delivery was significantly (P<0.05) greater among women who were overweight (3.7+/-0.1 days), obese (4.0+/-0.1 days), very obese (4.1+/-0.1 days), and extremely obese (4.4+/-0.1 days) than among women with normal BMI (3.6+/-0.1 days). A higher-than-normal BMI was associated with significantly more prenatal fetal tests, obstetrical ultrasonographic examinations, medications dispensed from the outpatient pharmacy, telephone calls to the department of obstetrics and gynecology, and prenatal visits with physicians. A higher-than-normal BMI was also associated with significantly fewer prenatal visits with nurse practitioners and physician assistants.

Most of the increase in length of stay associated with higher BMI was related to increased rates of cesarean delivery and obesity-related high-risk conditions.

Conclusions: Obesity during pregnancy is associated with increased use of health care services.”
“Purpose: Treatment in patients with seminoma who have residual or recurrent masses

following chemotherapy is still a matter of debate. Surgical resection is currently the most common recommendation for masses greater than 3 cm, resulting in overtreatment in up to 70% of those affected. We analyzed the accuracy of preoperative positron emission tomography for predicting viable tumor residuals in patients with seminoma.

Materials and Methods: In a prospective, multicenter trial computerized tomography and FDG (2-(F-18)-fluoro-2-deoxy-D-glucose) positron emission tomography were performed before surgical resection for residual or recurrent masses in 20 patients who had undergone Ispinesib chemotherapy for stage IIb, IIc or III seminoma. Histopathological findings were directly correlated with positron emission tomography results.

Results: Of the patients 18 presented with residual masses and 2 had recurrent masses following chemotherapy. Histopathological assessment revealed viable tumor in 3 patients and benign lesions in 17. All patients with viable tumor were identified correctly by positron emission tomography. No false-negative results were observed but 9 patients had false-positive positron emission tomography results.

Results: At 30 days, patients undergoing off-pump coronary artery

Results: At 30 days, patients undergoing off-pump coronary artery bypass grafting Crenolanib nmr had fewer events of bleeding (43.7% vs 56.3%, P = .0005) and myocardial infarction (7.3% vs 12.1%, P = .055) but higher rates of reintervention (3.7% vs 1.2%, P = .02). At 1 year, there was no difference between groups in death, total myocardial infarctions, reinterventions, strokes, or major adverse cardiac events, but there was a lower rate of non-Q-wave myocardial infarctions in the off-pump coronary artery bypass

grafting group (4.6% vs 9.2%, P = .03).

Conclusions: In this large-scale study evaluating the outcomes of patients with acute coronary syndromes, off-pump coronary artery bypass grafting was associated with lower rates of bleeding and non-Q-wave myocardial infarction but more reinterventions early after the procedure. At 1 year, there was no major outcome difference between the

2 surgical strategies. (J Thorac Cardiovasc Surg 2011;142:e33-9)”
“Rationale LCZ696 research buy Female rats display higher sensitivity to cocaine relative to males under a variety of conditions. Time-dependent increases in cocaine-seeking behavior (as measured by nonreinforced operant responses) during cocaine withdrawal have been reported in male, but not female, rats.

Objectives The present study determines sex and estrous cycle influences on time-dependent changes in cocaine-seeking check details behavior.

Materials and methods Male and female Sprague-Dawley rats were reinforced for “”active lever”" responses by a cocaine infusion (0.50 mg/kg/infusion, i.v., fixed ratio schedule of reinforcement, FR1) followed

by a 20-s time-out when reinforcement was not delivered. Infusions were paired with a light + tone conditioned stimulus. Next, rats underwent cocaine withdrawal for 1, 14, 60, or 180 days before testing cocaine-seeking behavior. Each rat was tested for extinction of operant responding, conditioned-cued reinstatement, and cocaine-primed (10 mg/kg, i.p.) reinstatement.

Results Both males and females displayed a time-dependent increase in cocaine-seeking behavior (active lever presses) under extinction of operant responding and conditioned-cued reinstatement conditions after 60 days of cocaine withdrawal. Moreover, cocaine-seeking behavior during extinction of operant responding in females, but not males, remained elevated at 180 days of cocaine withdrawal. Furthermore, females tested during estrus exhibited higher cocaine-seeking behavior under both extinction of operant responding and cocaine-primed reinstatement conditions relative to other rats independent of the duration of cocaine withdrawal.

Conclusions The effects of reproductive cycle and withdrawal duration on cocaine-seeking behavior are additive and time-dependent increases in cocaine-seeking behavior are more enduring in females than in male rats.


“A finite-population dynamic evolutionary model is present


“A finite-population dynamic evolutionary model is presented, which shows that increasing the individual capacity of sending pre-play signals (without any pre-defined

meaning), opens a route for cooperation. The population dynamics leads individuals to discriminate between different signals and react accordingly to the signals received. The proportion of time that the population spends in different states can be calculated analytically. We show that increasing the number of different signals benefits cooperative strategies, illustrating how cooperators may take profit from a diverse signaling portfolio to forecast future behaviors and avoid being cheated by defectors. (C) 2011 Elsevier JPH203 solubility dmso Ltd. All rights reserved.”
“The rubber hand illusion (RHI) occurs when a person misattributes a fake hand as his or her own hand. Previously, the RHI has been

examined with both the rubber hand and the participant’s real hand uncrossed with regards to the participant’s midline. The present study examined the strength of the illusion when the real hand, the fake hand or both hands are placed across the body midline. The illusion was induced by stroking the rubber hand and the real hand simultaneously. Asynchronous brushing served as a comparable condition since the RHI is not seen under these circumstances. Participants indicated where they felt their real hand was located by marking a sheet of paper under the table on which their unseen hand was placed. A significant RHI was observed with both the hands uncrossed. In contrast, no RHI was present when either hand was crossed over the midline. EPZ5676 mouse Additionally, a shift in hand judgment towards the midline was observed when participants crossed their real hand. These results indicate the importance of the midline in understanding representations OSI-027 in vivo of the body. (C) 2011 Elsevier Ireland Ltd. All rights reserved.”
“Shear stress, hormones like parathyroid and mineral elements like calcium mediate the amplitude of stimulus signal, which affects the rate of bone remodeling. The current study investigates the

theoretical effects of different metabolic doses in stimulus signal level on bone. The model was built considering the osteocyte as the sensing center mediated by coupled mechanical shear stress and some biological factors. The proposed enhanced model was developed based on previously published works dealing with different aspects of bone transduction. It describes the effects of physiological doses variations of calcium, parathyroid hormone, nitric oxide and prostaglandin E2 on the stimulus level sensed by osteocytes in response to applied shear stress generated by interstitial fluid flow. We retained the metabolic factors (parathyroid hormone, nitric oxide and prostaglandin E2) as parameters of bone cell mechanosensitivity because stimulation/inhibition of induced pathways stimulates osteogenic response in vivo.

However, there is not enough information about the kinetic mechan

However, there is not enough information about the kinetic mechanism of chlorophenols toxicity on the methanogenesis, which is a key aspect

for the control of the anaerobic digesters because of the sensitivity and the potential for energy recovery derived from methane release. The International Water Association-Anaerobic Digestion Model No. 1 (IWA-ADM1) can be adapted to a wide range of situations by updating or changing the equations BMS-754807 clinical trial in the model. The present study proposes a general kinetic model for methanogenesis. This model has been applied to predict the inhibition of methanogenesis by chlorophenols, and it can be used for updating the IWA-ADM1 when treating inhibitory compounds. The model was calibrated and validated using a wide broad of experimental sets of data of methane production by granular sludge in the presence of 2,4-dichlorophenol (24DCP), 2,4,6-trichlorophenol Selleck Etomoxir (246TCP) and pentachlorophenol (PCP) in batch assays. A lag-phase of the effect of chlorophenols on the methanogenesis by non-adapted sludge was detected and modeled by the kinetic model proposed. In addition, the inhibitory effect of PCP was more pronounced on the acetoclastic methanogenesis than on the hydrogenotrophic one. Non-competitive and uncompetitive inhibition types were detected using 24DCP and 246TCP, whereas a suicide or irreversible inhibition type was observed in the case of PCP. Values of inhibition constants considerably varied

depending on the chlorophenol used,

between 45 mg 24DCP L-1, 41-51 mg 246TCP L-1 and 0.9-7.8 mg PCP L-1. The higher toxicity of PCP is related with its hydrophobicity, which was determined by adsorption tests and using partition coefficients n-octanol/water. Modeling was accompanied by high statistical support in all cases, which confirmed the validation of the model proposed.”
“In acute ICG-001 solubility dmso depression a high prevalence of deficits in learning and memory performance has been reported. Still. it is unclear whether these cognitive deficits are present after remission of clinical symptoms of depression. The present study compared 20 inpatients recently remitted from severe major depressive disorder (MDD) with 20 healthy matched control participants on two sequence learning tasks: a modified serial reaction-time task (SRT) for implicit learning, which is sensitive to subcortical and frontal impairments, and a serial generation task (SGT) for explicit learning. As compared with performance in healthy controls, implicit and explicit learning were not impaired in recently remitted inpatients with depression. Intentional acquisition of new information was related to the severity of depressive symptoms as patients with higher scores on Beck’s Depression Inventory (BDI) showed poorer explicit learning. In contrast to findings in acute depression, our results suggest a normal degree of learning in remitted depression; these findings are consistent with unimpaired fronto-striatal functioning.


“The central role of adipose tissue in the development of


“The central role of adipose tissue in the development of cardiovascular and metabolic pathology

has been highlighted by the discovery of mediators (adipokines) secreted by adipose tissue and their involvement in the regulation of various biological processes. In light of recent experimental data, cross-talk between adipose tissue and the adrenal gland, particularly via the mineralocorticoid aldosterone, has been proposed. Aldosterone can induce adipogenesis, and human white adipose tissue is reported to release as-yet-uncharacterized Veliparib chemical structure factors that stimulate adrenocortical steroidogenesis and alclosterone production. These data could provide new insights into the pathophysiology of obesity-related disorders, including hypertension and alclosterone excess, with further studies necessary for confirming and better defining such adipose-adrenal interactions.”
“This paper is concerned with the theoretical study of two-dimensional peristaltic flow of power-law fluids in three layers with different viscosities. The analysis is carried out under low Reynolds number and long wavelength approximations. The shapes of the interfaces are described by a system of nonlinear algebraic equations which are solved numerically as streamlines. It

is found that the non-uniformity in the intermediate and peripheral SC75741 order layers diminishes when the viscosity of the intermediate layer is increased and that of the outermost layer is kept unaltered for both the pseudo-plastic and dilatant fluids. Similar are the observations when the viscosity of the outermost layer is increased and that of the intermediate layer is kept this website fixed. The flow rate increases with the viscosities of the peripheral and the intermediate layers but the viscosity of the outermost layer is more effective. However, the knowledge of the effect of the viscosity of the intermediate layer facilitates us to achieve the required flow rate without disturbing the outermost layer. An increase in the flow behaviour

index too favours larger flow rates. The trapping limits increase with the viscosity of the intermediate layer but decrease with the viscosity of the outermost layer and the flow behaviour index. Thus, a medicinal intervention that creates a more viscous intermediate layer and reduces pseudo plasticity may reduce constipation. (C) 2011 Elsevier Ltd. All rights reserved.”
“Ketamine, a noncompetitive N-methyl-D-aspartic acid (NMDA) receptor antagonist, is capable of triggering excessive glutamate release and subsequent cortical excitation which may induce psychosis-like behavior and cognitive anomalies. Growing evidence suggests that acute ketamine administration can provoke dose-dependent positive and negative schizophrenia-like symptoms.