Neurocircuit models of obsessive-compulsive disorder: limitations and future directions for research.

Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several neurocircuit models of OCD have been proposed with the aim of providing a better understanding of the neural and cognitive mechanisms involved in the disorder. These models use advances in neuroscience and findings from neuropsychological and neuroimaging studies to suggest links between clinical profiles that reflect the symptoms and experiences of patients and dysfunctions in specific neurocircuits. Several models propose that treatments for OCD could be improved if directed to specific neurocircuit dysfunctions, thereby restoring efficient neurocognitive function and ameliorating the symptomatology of each associated clinical profile. Yet, there are several important limitations to neurocircuit models of OCD. The purpose of the current review is to highlight some of these limitations, including issues related to the complexity of brain and cognitive function, the clinical presentation and course of OCD, etiological factors, and treatment methods proposed by the models. We also provide suggestions for future research to advance neurocircuit models of OCD and facilitate translation to clinical application.

Neurocircuit models of obsessive-compulsive disorder: limitations and future directions for research

Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several neurocircuit models of OCD have been proposed with the aim of providing a better understanding of the neural and cognitive mechanisms involved in the disorder. These models use advances in neuroscience and findings from neuropsychological and neuroimaging studies to suggest links between clinical profiles that reflect the symptoms and experiences of patients and dysfunctions in specific neurocircuits. Several models propose that treatments for OCD could be improved if directed to specific neurocircuit dysfunctions, thereby restoring efficient neurocognitive function and ameliorating the symptomatology of each associated clinical profile. Yet, there are several important limitations to neurocircuit models of OCD. The purpose of the current review is to highlight some of these limitations, including issues related to the complexity of brain and cognitive function, the clinical presentation and course of OCD, etiological factors, and treatment methods proposed by the models. We also provide suggestions for future research to advance neurocircuit models of OCD and facilitate translation to clinical application.

Lower Ventromedial Prefrontal Cortex Glutamate Levels in Patients With Obsessive-Compulsive Disorder.

Background: Recent studies using magnetic resonance spectroscopy (1H-MRS) indicate that patients with obsessive-compulsive disorder (OCD) present abnormal levels of glutamate (Glu) and gamma aminobutyric acid (GABA) in the frontal and striatal regions of the brain. These abnormalities could be related to the hyperactivation observed in cortico-striatal circuits of patients with OCD. However, most of the previous 1H-MRS studies were not capable of differentiating the signal from metabolites that overlap in the spectrum, such as Glu and glutamine (Gln), and referred to the detected signal as the composite measure-Glx (sum of Glu and Gln). In this study, we used a two-dimensional JPRESS 1H-MRS sequence that allows the discrimination of overlapping metabolites by observing the differences in J-coupling, leading to higher accuracy in the quantification of all metabolites. Our objective was to identify possible alterations in the neurometabolism of OCD, focusing on Glu and GABA, which are key neurotransmitters in the brain that could provide insights into the underlying neurochemistry of a putative excitatory/inhibitory imbalance. Secondary analysis was performed including metabolites such as Gln, creatine (Cr), N-acetylaspartate, glutathione, choline, lactate, and myo-inositol. Methods: Fifty-nine patients with OCD and 42 healthy controls (HCs) underwent 3T 1H-MRS in the ventromedial prefrontal cortex (vmPFC, 30 × 25 × 25 mm3). Metabolites were quantified using ProFit (version 2.0) and Cr as a reference. Furthermore, Glu/GABA and Glu/Gln ratios were calculated. Generalized linear models (GLMs) were conducted using each metabolite as a dependent variable and age, sex, and gray matter fraction (fGM) as confounding factors. GLM analysis was also used to test for associations between clinical symptoms and neurometabolites. Results: The GLM analysis indicated lower levels of Glu/Cr in patients with OCD (z = 2.540; p = 0.011). No other comparisons reached significant differences between groups for all the metabolites studied. No associations between metabolites and clinical symptoms were detected. Conclusions: The decreased Glu/Cr concentrations in the vmPFC of patients with OCD indicate a neurochemical imbalance in the excitatory neurotransmission that could be associated with the neurobiology of the disease and may be relevant for the pathophysiology of OCD.

Skin picking treatment with the Rothbaum cognitive behavioral therapy protocol: a randomized clinical trial

Introduction: Although behavioral therapies can effectively treat skin picking disorder (SPD), there is no standardized treatment for improving SPD and its comorbidities and there is no group intervention option. This trial aimed to adapt the Rothbaum trichotillomania protocol to SPD (Study 1) and test its efficacy for treating SPD and comorbidities in individual and group formats (Study 2). Methods: The adapted protocol was applied to 16 SPD patients, who were allocated to group or individual treatment (Study 1). Afterwards, 54 patients were randomly allocated to treatment in an individual (n=27) or group format (n=27) (Study 2). In both studies, assessments of SPD severity, anxiety, depression, clinical status and skin lesion severity were performed at baseline and the endpoint. Results: The adapted protocol was feasible in both treatment modalities (Study 1) and led to high SPD remission rates (individual 63%; group 52%), with no significant difference between intervention types (p = 0.4) (Study 2). SPD, anxiety, and depression symptoms and objective patient lesion measures improved after treatment. There was large effect size for SPD symptom improvement in both treatment types (Cohen's d: group = 0.88; individual = 1.15) (Study 2). Conclusion: The adapted Rothbaum protocol was effective for SPD remission, comorbidities, and skin lesions, both in individual and group formats. Clinical trial registration: NCT03182478

Skin picking treatment with the Rothbaum cognitive behavioral therapy protocol: a randomized clinical trial.

INTRODUCTION: Although behavioral therapies can effectively treat skin picking disorder (SPD), there is no standardized treatment for improving SPD and its comorbidities and there is no group intervention option. This trial aimed to adapt the Rothbaum trichotillomania protocol to SPD (Study 1) and test its efficacy for treating SPD and comorbidities in individual and group formats (Study 2). METHODS: The adapted protocol was applied to 16 SPD patients, who were allocated to group or individual treatment (Study 1). Afterwards, 54 patients were randomly allocated to treatment in an individual (n=27) or group format (n=27) (Study 2). In both studies, assessments of SPD severity, anxiety, depression, clinical status and skin lesion severity were performed at baseline and the endpoint. RESULTS: The adapted protocol was feasible in both treatment modalities (Study 1) and led to high SPD remission rates (individual 63%; group 52%), with no significant difference between intervention types (p = 0.4) (Study 2). SPD, anxiety, and depression symptoms and objective patient lesion measures improved after treatment. There was large effect size for SPD symptom improvement in both treatment types (Cohen's d: group = 0.88; individual = 1.15) (Study 2). CONCLUSION: The adapted Rothbaum protocol was effective for SPD remission, comorbidities, and skin lesions, both in individual and group formats. CLINICAL TRIAL REGISTRATION: NCT03182478.

New hybrid trifluoromethylquinolines as antiplasmodium agents.

Malaria remains a major public health problem worldwide, and it is responsible for high rates of morbidity and mortality. Resistance to current antimalarial drugs has been identified, and new drugs are urgently needed. In this study, we designed and synthesized seventeen novel quinolines based on the structures of mefloquine ((2,8-bis(trifluoromethyl)quinolin-4-yl)(piperidin-2-yl)methanol) and amodiaquine (4-((7-chloroquinolin-4-yl)amino)-2-((diethylamino)methyl)phenol) using ring bioisosteric replacement and molecular hybridization of the functional groups. The compounds were evaluated in vitro against Plasmodium falciparum and in vivo in mice infected with P. berghei. All derivatives presented anti-P. falciparum activity with IC50 values ranging from 0.083 to 33.0 µM. The compound with the best anti-P. falciparum activity was N-(5-methyl-4H-1,2,4-triazol-3-yl)-2,8-bis(trifluoromethyl)quinolin-4-amine (12) which showed an IC50 of 0.083 µM. The three most active compounds were selected for antimalarial activity tests against P. berghei-infected mice. Compound 12 was the most active on the 5th day after infection, reducing parasitemia by 66%, which is consistent with its in vitro activity. This is an important result as 12, a simpler molecule than mefloquine, does not contain the stereogenic center, and consequently, its synthesis in the laboratory is easier and less expensive. This system proved promising for the design of potential antimalarial compounds.

Characterization of ciliate diversity in bromeliad tank waters from the Brazilian Atlantic Forest.

Bromeliads are a diverse group of plants that includes many species whose individuals are capable of retaining water, forming habitats called phytotelmata. These habitats harbor a diversity of organisms including prokaryotes, unicellular eukaryotes, metazoans, and fungi. Among single-celled eukaryotic organisms, ciliates are generally the most abundant. In the present study, we used Illumina DNA sequencing to survey the eukaryotic communities, especially ciliates, inhabiting the tanks of the bromeliads Aechmea gamosepala and Vriesea platynema in the Atlantic Forest of southern Brazil. Filtered sequences were clustered into distinct OTUs using a 99% identity threshold, and then assigned to phylum and genus using a BLAST-based approach (implemented in QIIME) and the SILVA reference database. Both bromeliad species harbored very diverse eukaryotic communities, with Arthropoda and Ciliophora showing the highest abundance (as estimated by the number of sequence reads). The ciliate genus Tetrahymena was the most abundant among single-celled organisms, followed by apicomplexan gregarines and the ciliate genus Glaucoma. Another interesting finding was the presence and high abundance of Trypanosoma in these bromeliad tanks, demonstrating their occurrence in this type of environment. The results presented here demonstrate a hidden diversity of eukaryotes in bromeliad tank waters, opening up new avenues for their in-depth characterization.

Ophthalmic diagnostic tests in captive red-footed tortoises (Chelonoidis carbonaria) in Salvador, northeast Brazil.

PURPOSE: The aim of this study was to establish normal ophthalmic parameters for select diagnostic tests in red-footed tortoises (Chelonoides carbonaria). A total of 52 animals, approximately 20-30 years old, were studied. METHOD: Ophthalmic diagnostic tests included culturing of the normal conjunctival bacterial flora in summer and winter, evaluation of tear production using Schirmer tear test (STT) and endodontic absorbent paper point tear test in two different environmental temperatures (EAPPTT-1 at 32 °C and EAPPTT-2 at 18 °C), cytology of conjunctival cells, B-mode ultrasonography, measurement of palpebral fissure length (PFL), and applanation tonometry (in two different positions). RESULTS: In both seasons, Gram-positive bacteria were predominant. Median (± IQR/2) STT was 12.0 ± 3.5 mm/min, EAPPTT-1 was 15.9 ± 0.7 mm/15 s, and EAPPTT-2 was 15.4 ± 0.4 mm/min (OD) and 17.8 ± 1.0 mm/min (OS). Anterior chamber depth was 1.0 ± 0.1 mm, lens axial length was 2.3 ± 0.1 mm, vitreous chamber depth was 4.3 ± 0.2 mm, and axial globe length was 7.7 ± 0.3 mm. PFL was 11.7 ± 1.7 mm. Intraocular pressure was 11.5 ± 2.8 mmHg for males and 14.0 ± 3.5 mmHg for females (dorsoventral position) and 18.0 ± 3.2 mmHg for males and 24.1 ± 3.0 mmHg for females (ventrodorsal position with inclination of 45°). The ophthalmic parameters reported here can aid in the diagnosis of eye diseases in red-footed tortoises (Chelonoides carbonaria).