Cognitive and clinical predictors of a long-term course in obsessive compulsive disorder: A machine learning approach in a prospective cohort study

BACKGROUND

Obsessive compulsive disorder (OCD) is a disabling illness with a chronic course, yet data on long-term outcomes are scarce. This study aimed to examine the long-term course of OCD in patients treated with different approaches (drugs, psychotherapy, and psychosurgery) and to identify predictors of clinical outcome by machine learning.

METHOD

We included outpatients with OCD treated at our referral unit. Demographic and neuropsychological data were collected at baseline using standardized instruments. Clinical data were collected at baseline, 12 weeks after starting pharmacological treatment prescribed at study inclusion, and after follow-up.

RESULTS

Of the 60 outpatients included, with follow-up data available for 5-17 years (mean = 10.6 years), 40 (67.7 %) were considered non-responders to adequate treatment at the end of the study. The best machine learning model achieved a correlation of 0.63 for predicting the long-term Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score by adding clinical response (to the first pharmacological treatment) to the baseline clinical and neuropsychological characteristics.

LIMITATIONS

Our main limitations were the sample size, modest in the context of traditional ML studies, and the sample composition, more representative of rather severe OCD cases than of patients from the general community.

CONCLUSIONS

Many patients with OCD showed persistent and disabling symptoms at the end of follow-up despite comprehensive treatment that could include medication, psychotherapy, and psychosurgery. Machine learning algorithms can predict the long-term course of OCD using clinical and cognitive information to optimize treatment options.

Pathogenic missense variation in PABPC1L/EPAB causes female infertility due to oocyte maturation arrest at the germinal vesicle stage

Women undergoing controlled ovarian hyperstimulation prior to in vitro fertilization (IVF) are treated using various protocols to induce multiple follicular growths. Complete failure of all oocytes to mature during IVF cycles is rare; however, it is a known cause of primary female infertility. Recently, pathogenic variations in a few genes have been identified in women with oocyte maturation defects; however, the underlying genetic causes remain largely unknown.This study included a Turkish family comprising three sisters with recurring oocyte maturation arrest at the germinal vesicle stage after multiple ovarian stimulations. Exome sequencing revealed a homozygous missense variant (c.1037C>T, p.Ala346Val) in the EPAB gene (also known as PABPC1L) in all three affected sisters, which was either absent or heterozygous in the unaffected family members. Functional experiments confirming the pathogenicity of the variant were performed by transfecting HEK293T cells and demonstrated the instability and increased rate of proteolysis of the mutated PABPC1L/EPAB protein. The identified variant, located in the well-conserved fourth RNA recognition motif (RRM4), in silico 3D modelling suggested changes in the physical properties of the pathogenic variant of PABPC1L/EPAB. Our findings validate PABPC1L/EPAB as an essential genetic contributor to the oocyte maturation process in humans and have direct implications for the genetic counselling of patients and their family members.

The genomics of visuospatial neurocognition in obsessive-compulsive disorder: A preliminary GWAS

BACKGROUND

The study of Obsessive-Compulsive Disorder (OCD) genomics has primarily been tackled by Genome-wide association studies (GWAS), which have encountered troubles in identifying replicable single nucleotide polymorphisms (SNPs). Endophenotypes have emerged as a promising avenue of study in trying to elucidate the genomic bases of complex traits such as OCD.

METHODS

We analyzed the association of SNPs across the whole genome with the construction of visuospatial information and executive performance through four neurocognitive variables assessed by the Rey-Osterrieth Complex Figure Test (ROCFT) in a sample of 133 OCD probands. Analyses were performed at SNP- and gene-level.

RESULTS

No SNP reached genome-wide significance, although there was one SNP almost reaching significant association with copy organization (rs60360940; P = 9.98E-08). Suggestive signals were found for the four variables at both SNP- (P < 1E-05) and gene-levels (P < 1E-04). Most of the suggestive signals pointed to genes and genomic regions previously associated with neurological function and neuropsychological traits.

LIMITATIONS

Our main limitations were the sample size, which was limited to identify associated signals at a genome-wide level, and the composition of the sample, more representative of rather severe OCD cases than a population-based OCD sample with a broad severity spectrum.

CONCLUSIONS

Our results suggest that studying neurocognitive variables in GWAS would be more informative on the genetic basis of OCD than the classical case/control GWAS, facilitating the genetic characterization of OCD and its different clinical profiles, the development of individualized treatment approaches, and the improvement of prognosis and treatment response.

Neuropsychological performance and predictors of pharmacological treatment response in obsessive compulsive disorder

BACKGROUND

Obsessive Compulsive Disorder (OCD) is characterized by the presence of executive dysfunctions. As organizational strategies may play an important role as a possible endophenotype of the disorder, we decided to investigate non-verbal memory and organizational abilities in OCD. We also investigated how organization and non-verbal memory differ between responder and non-responder patients to pharmacological treatment, to test whether cognitive functions can predict the response to pharmacological treatment.

METHODS

In Study 1, executive and clinical functioning measures were applied to 162 OCD and 95 controls. In Study 2, clinical, intelligence and executive functioning measures were applied to 72 OCD responders and 63 OCD non-responder patients.

RESULTS

OCD patients and controls from Study 1 differed in copy organization (p < 0.01) and delayed recall (p = 0.048). In Study 2, the OCD responders displayed better copy organization (p = 0.013) and lower depressive, anxious and OCD symptoms (p < 0.01 in the three cases). Scores in the following instruments were found to predict the response to pharmacological treatment: HDRS, Y-BOCS, Raven progressive matrices, and Direct digit subtest from the Wechsler's scale (p < 0.01 in all four cases).

LIMITATIONS

In Study 1, the imbalance of the sample can be considered a limitation, whilst in Study 2, some of the levels of pharmacological resistance were not represented.

CONCLUSIONS

In this study, non-verbal memory and organization was affected in OCD. Responder patients also displayed better executive functioning and fluid intelligence. Organizational ability is a predictor of pharmacological response to SSRI monotherapy in a predictive model controlling for anxious symptoms.

How is COVID-19 affecting patients with obsessive-compulsive disorder? A longitudinal study on the initial phase of the pandemic in a Spanish cohort

BACKGROUND

Although the consequences of the COVID-19 pandemic on emotional health are evident, little is known about its impact on patients with obsessive-compulsive disorder (OCD).

METHODS

One hundred and twenty-seven patients with OCD who attended a specialist OCD Clinic in Barcelona, Spain, were assessed by phone from April 27 to May 25, 2020, during the early phase of the pandemic, using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and a structured interview that collected clinical and sociodemographic information. Results were compared with those for 237 healthy controls from the same geographic area who completed an online survey.

RESULTS

Although 65.3% of the patients with OCD described a worsening of their symptoms, only 31.4% had Y-BOCS scores that increased >25%. The risk of getting infected by SARS-CoV2 was reported as a new obsession by 44.8%, but this only became the main obsessive concern in approximately 10% of the patients. Suicide-related thoughts were more frequent among the OCD cohort than among healthy controls. The presence of prepandemic depression, higher Y-BOCS scores, contamination/washing symptoms, and lower perceived social support all predicted a significantly increased risk of OCD worsening.

CONCLUSIONS

Most patients with OCD appear to be capable of coping with the emotional stress of the COVID-19 outbreak and its consequences during the initial phase of the pandemic. Nevertheless, the current crisis constitutes a risk factor for a significant worsening of symptoms and suicidal ideation. Action is needed to ensure effective and individualized follow-up care for patients with OCD in the COVID-19 era.

Neurofunctional predictive biomarkers of cognitive-behavioral therapy during fear conditioning in patients with obsessive-compulsive disorder

Introduction

Altered fear learning processes could be mechanistically linked to the development and/or maintenance of obsessive-compulsive disorder (OCD). From a clinical perspective, the first-line psychological treatment for OCD is cognitive-behavioral therapy (CBT), which is based on the principles of fear learning. However, no previous functional magnetic resonance imaging (fMRI) studies have evaluated the predictive capacity of regional brain activations during fear learning on CBT response in patients with OCD.

Objectives

We aimed at exploring whether brain activation during fear learning in patients with OCD are associated with CBT outcome.

Methods

We assessed 18 patients with OCD and 18 healthy participants during a 2-day experimental protocol where brain activation and skin conductance responses (SCR) where assessed during fear conditioning, extinction learning, and extinction recall within the fMRI scanner. Following the protocol, patients with OCD received CBT.

Results

We found non-significant between-group differences in SCR during fear learning. Patients with OCD showed significantly diminished activation of the dorsal anterior cingulate cortex and the right insula during fear conditioning. Importantly, our analyses revealed a significant negative association between clinical improvement after CBT and activity at the right insula during fear conditioning (x = 39, y = 12, z = -11; t = 5.64; p<0.001; k = 928). This finding is displayed in Figure 1 below.

Conclusions

Patients with OCD may require less fear-conditioned brain responses to achieve the same level of psychophysiological fear conditioning as healthy participants. Interestingly, insula activations during fear-conditioned responses may represent a potential predictor biomarker of response to CBT for OCD.

Disclosure

No significant relationships.

Is glutamate associated with fear extinction and cognitive behavior therapy outcome in OCD? A pilot study

Cognitive behavioral therapy (CBT) including exposure and response prevention is a well-established treatment for obsessive-compulsive disorder (OCD) and is based on the principles of fear extinction. Fear extinction is linked to structural and functional variability in the ventromedial prefrontal cortex (vmPFC) and has been consistently associated with glutamate neurotransmission. The relationship between vmPFC glutamate and fear extinction and its effects on CBT outcome have not yet been explored in adults with OCD. We assessed glutamate levels in the vmPFC using 3T magnetic resonance spectroscopy, and fear extinction (learning and recall) using skin conductance responses during a 2-day experimental paradigm in OCD patients (n = 17) and in healthy controls (HC; n = 13). Obsessive-compulsive patients (n = 12) then received manualized CBT. Glutamate in the vmPFC was negatively associated with fear extinction recall and positively associated with CBT outcome (with higher glutamate levels predicting a better outcome) in OCD patients. Glutamate levels in the vmPFC in OCD patients were not significantly different from those in HC, and were not associated with OCD severity. Our results suggest that glutamate in the vmPFC is associated with fear extinction recall and CBT outcome in adult OCD patients.

A Class of Potent Inhibitors of the HIV-1 Nucleocapsid Protein Based on Aminopyrrolic Scaffolds

The HIV-1 nucleocapsid protein 7 (NC) is a potential target for effective antiretroviral therapy due to its central role in virus replication, mainly linked to nucleic acid (NA) chaperone activity, and low susceptibility to drug resistance. By screening a compounds library, we identified the aminopyrrolic compound CN14_17, a known carbohydrate binding agent, that inhibits the NC chaperone activity in the low micromolar range. Different from most of available NC inhibitors, CN14_17 fully prevents the NC-induced annealing of complementary NA sequences. Using fluorescence assays and isothermal titration calorimetry, we found that CN14_17 competes with NC for the binding to NAs, preferentially targeting single-stranded sequences. Molecular dynamics simulations confirmed that binding to cTAR occurs preferably within the guanosine-rich single stranded sequence. Finally, CN14_17 exhibited antiretroviral activity in the low micromolar range, although with a moderate therapeutic index. Overall, CN14_17 might be the progenitor of a new promising class of NC inhibitors.

Altered functional connectivity of the subthalamus and the bed nucleus of the stria terminalis in obsessive-compulsive disorder

BACKGROUND

The assessment of inter-regional functional connectivity (FC) has allowed for the description of the putative mechanism of action of treatments such as deep brain stimulation (DBS) of the nucleus accumbens in patients with obsessive-compulsive disorder (OCD). Nevertheless, the possible FC alterations of other clinically-effective DBS targets have not been explored. Here we evaluated the FC patterns of the subthalamic nucleus (STN) and the bed nucleus of the stria terminalis (BNST) in patients with OCD, as well as their association with symptom severity.

METHODS

Eighty-six patients with OCD and 104 healthy participants were recruited. A resting-state image was acquired for each participant and a seed-based analysis focused on our two regions of interest was performed using statistical parametric mapping software (SPM8). Between-group differences in FC patterns were assessed with two-sample t test models, while the association between symptom severity and FC patterns was assessed with multiple regression analyses.

RESULTS

In comparison with controls, patients with OCD showed: (1) increased FC between the left STN and the right pre-motor cortex, (2) decreased FC between the right STN and the lenticular nuclei, and (3) increased FC between the left BNST and the right frontopolar cortex. Multiple regression analyses revealed a negative association between clinical severity and FC between the right STN and lenticular nucleus.

CONCLUSIONS

This study provides a neurobiological framework to understand the mechanism of action of DBS on the STN and the BNST, which seems to involve brain circuits related with motor response inhibition and anxiety control, respectively.

Brain structural correlates of obsessive-compulsive disorder with and without preceding stressful life events

Objectives There is growing evidence supporting a role for stressful life events (SLEs) at obsessive-compulsive disorder (OCD) onset, but neurobiological correlates of such effect are not known. We evaluated regional grey matter (GM) changes associated with the presence/absence of SLEs at OCD onset. Methods One hundred and twenty-four OCD patients and 112 healthy controls were recruited. Patients were split into two groups according to the presence (n = 56) or absence (n = 68) of SLEs at disorder's onset. A structural magnetic resonance image was acquired for each participant and pre-processed with Statistical Parametric Mapping software (SPM8) to obtain a volume-modulated GM map. Between-group differences in sociodemographic, clinical and whole-brain regional GM volumes were assessed. Results SLEs were associated with female sex, later age at disorder's onset, more contamination/cleaning and less hoarding symptoms. In comparison with controls, patients without SLEs showed GM volume increases in bilateral dorsal putamen and the central tegmental tract of the brainstem. By contrast, patients with SLEs showed specific GM volume increases in the right anterior cerebellum. Conclusions Our findings support the idea that neuroanatomical alterations of OCD patients partially depend on the presence of SLEs at disorder's onset.

Exon-focused genome-wide association study of obsessive-compulsive disorder and shared polygenic risk with schizophrenia

Common single-nucleotide polymorphisms (SNPs) account for a large proportion of the heritability of obsessive-compulsive disorder (OCD). Co-ocurrence of OCD and schizophrenia is commoner than expected based on their respective prevalences, complicating the clinical management of patients. This study addresses two main objectives: to identify particular genes associated with OCD by SNP-based and gene-based tests; and to test the existence of a polygenic risk shared with schizophrenia. The primary analysis was an exon-focused genome-wide association study of 370 OCD cases and 443 controls from Spain. A polygenic risk model based on the Psychiatric Genetics Consortium schizophrenia data set (PGC-SCZ2) was tested in our OCD data. A polygenic risk model based on our OCD data was tested on previous data of schizophrenia from our group. The most significant association at the gene-based test was found at DNM3 (P=7.9 × 10(-5)), a gene involved in synaptic vesicle endocytosis. The polygenic risk model from PGC-SCZ2 data was strongly associated with disease status in our OCD sample, reaching its most significant value after removal of the major histocompatibility complex region (lowest P=2.3 × 10(-6), explaining 3.7% of the variance). The shared polygenic risk was confirmed in our schizophrenia data. In conclusion, DNM3 may be involved in risk to OCD. The shared polygenic risk between schizophrenia and OCD may be partially responsible for the frequent comorbidity of both disorders, explaining epidemiological data on cross-disorder risk. This common etiology may have clinical implications.

Brain regions related to fear extinction in obsessive-compulsive disorder and its relation to exposure therapy outcome: a morphometric study

BACKGROUND

The size of particular sub-regions within the ventromedial prefrontal cortex (vmPFC) has been associated with fear extinction in humans. Exposure therapy is a form of extinction learning widely used in the treatment of obsessive-compulsive disorder (OCD). Here we investigated the relationship between morphometric measurements of different sub-regions of the vmPFC and exposure therapy outcome in OCD.

METHOD

A total of 74 OCD patients and 86 healthy controls underwent magnetic resonance imaging (MRI). Cortical thickness and volumetric measurements were obtained for the rostral anterior cingulate cortex (rACC), the medial orbital frontal cortex and the subcallosal cortex. After MRI acquisition, patients were enrolled in an exposure therapy protocol, and we assessed the relationship between MRI-derived measurements and treatment outcome. Baseline between-group differences for such measurements were also assessed.

RESULTS

Compared with healthy controls, OCD patients showed a thinner left rACC (p = 0.008). Also, left rACC thickness was inversely associated with exposure therapy outcome (r - 0.32, p = 0.008), and this region was significantly thinner in OCD patients who responded to exposure therapy than in those who did not (p = 0.006). Analyses based on regional volumetry did not yield any significant results.

CONCLUSIONS

OCD patients showed cortical thickness reductions in the left rACC, and these alterations were related to exposure therapy outcome. The precise characterization of neuroimaging predictors of treatment response derived from the study of the brain areas involved in fear extinction may optimize exposure therapy planning in OCD and other anxiety disorders.

Interaction of SLC1A1 gene variants and life stress on pharmacological resistance in obsessive-compulsive disorder

Genetic and environmental factors seem to interact and influence both the onset and the course of obsessive-compulsive disorder (OCD), but the role of glutamate transporter variants (SLC1A1) in pharmacological resistance is not known. We aimed to assess whether genetic variants in SLC1A1 and life stress at onset of the disorder interact and modulate pharmacological resistance in OCD. A single-marker association study of several single-nucleotide polymorphisms in the SLC1A1 genomic region was performed in a sample of 238 OCD patients. For the most strongly associated SNP (rs3087879), one copy of the risk allele increased the probability of higher treatment resistance (odds ratio=2.42; 95% confidence interval=1.39-4.21; P=0.0018), but only in OCD patients without life stress at onset of the disorder. These results suggest a gene-by-environment interaction effect on treatment resistance in OCD and strengthen the existing evidence of the role of the glutamatergic system in the phenomenology of OCD.

Variation in the BDNF Val66Met polymorphism and response to cognitive-behavior therapy in obsessive-compulsive disorder

BACKGROUND

Recent research suggests that the brain-derived neurotrophic factor (BDNF) may play a role in extinction learning. The goal of this study was to test whether variation in the BDNF Val66Met polymorphism is related to treatment response to exposure-based cognitive-behavior therapy (CBT), a form of extinction learning, in obsessive-compulsive disorder (OCD).

METHODS

One hundred and six OCD patients from a specialized clinic, who underwent a standardized CBT treatment after partial or non-response to a 12-week pharmacological trial, were genotyped for the BDNF Val66Met and the relationship between genotype and treatment response was analyzed.

RESULTS

Among 98 CBT completers, 36% of those carrying the BDNF Met allele were rated as CBT responders compared to 60% of nonMet allele carriers (P=0.027). When analyzing the different obsessive-compulsive symptom dimensions, in patients with contamination/cleaning symptoms, the Met allele was associated with a significantly worse CBT response (P<0.0001) and a lower obsessions severity decrease from pre- to posttreatment (P=0.046).

CONCLUSION

Genetic variation in BDNF may be associated with treatment response in exposure-based CBT in OCD, especially in those patients exhibiting contamination/cleaning symptoms.

Variants in estrogen receptor alpha gene are associated with phenotypical expression of obsessive-compulsive disorder

Compelling data from animal and clinical studies suggest that sex steroids may play a role in the etiopathology of obsessive-compulsive disorder (OCD). The aim of this study was to investigate whether variants in estrogen receptor genes ESR1 and ESR2 may contribute to the genetic susceptibility to OCD, through a case-control association study using an extensive linkage disequilibrium-mapping approach. Twenty tag single-nucleotide polymorphisms (tagSNPs) covering the ESR2 region and nine tagSNPS from regions of ESR1 reported to be related to transcriptional control were genotyped in 229 OCD patients and 279 controls. SNP association and haplotype analysis were performed. The association of these genes and OCD subphenotypes was tested, considering early-onset OCD, comorbid tic and affective disorders, and OCD symptom dimensions. No significant difference in the distribution of alleles or genotypes was detected between controls and OCD subjects. Nevertheless, on analyzing OCD subphenotypes, SNP rs34535804 in ESR1 and a five SNPs haplotype, located at the 5' end of intron 1 of ESR1, were associated with the presence of contamination obsessions and cleaning compulsions. Specifically, carriers of the ACCCG haplotype, a combination of functional alleles related to higher ER alpha expression, showed a reduced risk of suffering from these symptoms. Our results suggest that the ESR1 gene may contribute to the genetic vulnerability to certain OCD manifestations. The dissection of OCD into more homogeneous subphenotypes may well help to identify susceptibility genes for the disorder.

Memory and strategic processing in first-degree relatives of obsessive compulsive patients

BACKGROUND

The same executive dysfunctions and alterations in neuroimaging tests (both functional and structural) have been found in obsessive-compulsive patients and their first-degree relatives. These neurobiological findings are considered to be intermediate markers of the disease. The aim of our study was to assess verbal and non-verbal memory in unaffected first-degree relatives, in order to determine whether these neuropsychological functions constitute a new cognitive marker for obsessive-compulsive disorder (OCD).

METHOD

Recall and use of organizational strategies in verbal and non-verbal memory tasks were measured in 25 obsessive-compulsive patients, 25 unaffected first-degree relatives and 25 healthy volunteers.

RESULTS

First-degree relatives and healthy volunteers did not show differences on most measures of verbal memory. However, during the recall and processing of non-verbal information, deficits were found in first-degree relatives and patients compared with healthy volunteers.

CONCLUSIONS

The presence of the same deficits in the execution of non-verbal memory tasks in OCD patients and unaffected first-degree relatives suggests the influence of certain genetic and/or familial factors on this cognitive function in OCD and supports the hypothesis that deficits in non-verbal memory tasks could be considered as cognitive markers of the disorder.

Comorbidity in pathological gambling: clinical variables, personality and treatment response

INTRODUCTION

Pathological gambling shows high comorbidity rates, especially with substance use disorders, although affective, anxiety and other impulse control disorders, as well as personality disorders, are also frequently associated.

OBJECTIVES

To explore comorbidity in pathological gambling with other mental disorders in a consecutive sample of patients attending a unit specialized in pathological gambling, and specifically the relationship between substance-related disorders, on the one hand, and personality and clinical variables in pathological gamblers, on the other.

METHOD

A total of 498 patients with a DSM-IV-TR diagnosis of Pathological Gambling (11.8% women) were assessed with a semi-structured clinical interview and several clinical and personality scales.

RESULTS

Higher comorbidity with affective disorders was found in women (30.5%), while higher comorbidity with substance-related disorders was found in men (11.2%). A positive association was also detected between a history of psychiatric disorders and current comorbidity with substance-use disorders, as well as between alcohol abuse and age. Finally, some personality traits such as low reward dependence (OR=0.964) and high impulsivity (OR=1.02) predicted other substance abuse (not alcohol). High selftranscendence scores predicted both alcohol and other substance abuse (OR=1.06).

CONCLUSIONS

Our results suggest a high prevalence of comorbid disorders in pathologic gambling, mainly with affective and substance-related disorders. The results of the present study, conducted in a broad sample of consecutively admitted pathologic gamblers, may contribute to understanding of this complex disorder and treatment improvement.

Genetic susceptibility to obsessive-compulsive hoarding: the contribution of neurotrophic tyrosine kinase receptor type 3 gene

Recent work suggests that neurotrophic factors may contribute to the genetic susceptibility to obsessive-compulsive disorder (OCD). Among other clinical dimensions, the presence of hoarding obsessions and compulsions has been shown to be correlated with a number of clinical and neuroimaging findings, as well as with a different pattern of genetic inheritance. We used a linkage disequilibrium (LD)-mapping approach to investigate whether neurotrophic tyrosine kinase receptor type 3 (NTRK3), the high-affinity receptor of neurotrophin 3 (NT-3), plays a role in increasing susceptibility to hoarding in OCD. We performed an association study of 52 tag single nucleotide polymorphisms (tagSNPs) covering the whole NTRK3 gene in a sample comprising 120 OCD patients and 342 controls. Single nucleotide polymorphism association and haplotype analysis were performed. Thirty-six of our patients (30%) exhibited significant hoarding obsessions and compulsions. A significant association of two SNPs in the 3' downstream region of NTRK3 gene and obsessive-compulsive hoarding was identified: rs1017412 [odds ratio (OR) = 2.16; P = 0.001] and rs7176429 (OR = 2.78; P = 0.0001), although only the latter remained significant after Bonferroni correction. Although the haplotype analysis did not show significant results, a more extended block of LD in the OCD hoarders with respect to the control group was observed, suggesting a lower haplotype diversity in these individuals. Our findings suggest that NTRK3 may contribute to the genetic susceptibility to hoarding in OCD and may constitute an interesting gene to focus on in studies of the genetic basis of obsessive-compulsive hoarding.

Mitochondrial dysfunction in lyssavirus-induced apoptosis

Lyssaviruses are highly neurotropic viruses associated with neuronal apoptosis. Previous observations have indicated that the matrix proteins (M) of some lyssaviruses induce strong neuronal apoptosis. However, the molecular mechanism(s) involved in this phenomenon is still unknown. We show that for Mokola virus (MOK), a lyssavirus of low pathogenicity, the M (M-MOK) targets mitochondria, disrupts the mitochondrial morphology, and induces apoptosis. Our analysis of truncated M-MOK mutants suggests that the information required for efficient mitochondrial targeting and dysfunction, as well as caspase-9 activation and apoptosis, is held between residues 46 and 110 of M-MOK. We used a yeast two-hybrid approach, a coimmunoprecipitation assay, and confocal microscopy to demonstrate that M-MOK physically associates with the subunit I of the cytochrome c (cyt-c) oxidase (CcO) of the mitochondrial respiratory chain; this is in contrast to the M of the highly pathogenic Thailand lyssavirus (M-THA). M-MOK expression induces a significant decrease in CcO activity, which is not the case with M-THA. M-MOK mutations (K77R and N81E) resulting in a similar sequence to M-THA at positions 77 and 81 annul cyt-c release and apoptosis and restore CcO activity. As expected, the reverse mutations, R77K and E81N, introduced in M-THA induce a phenotype similar to that due to M-MOK. These features indicate a novel mechanism for energy depletion during lyssavirus-induced apoptosis.

Rabies virus matrix protein interplay with eIF3, new insights into rabies virus pathogenesis

Viral proteins are frequently multifunctional to accommodate the high density of information encoded in viral genomes. Matrix (M) protein of negative-stranded RNA viruses such as Rhabdoviridae is one such example. Its primary function is virus assembly/budding but it is also involved in the switch from viral transcription to replication and the concomitant down regulation of host gene expression. In this study we undertook a search for potential rabies virus (RV) M protein's cellular partners. In a yeast two-hybrid screen the eIF3h subunit was identified as an M-interacting cellular factor, and the interaction was validated by co-immunoprecipitation and surface plasmon resonance assays. Upon expression in mammalian cell cultures, RV M protein was localized in early small ribosomal subunit fractions. Further, M protein added in trans inhibited in vitro translation on mRNA encompassing classical (Kozak-like) 5′-UTRs. Interestingly, translation of hepatitis C virus IRES-containing mRNA, which recruits eIF3 via a different noncanonical mechanism, was unaffected. Together, the data suggest that, as a complement to its functions in virus assembly/budding and regulation of viral transcription, RV M protein plays a role in inhibiting translation in virus-infected cells through a protein–protein interaction with the cellular translation machinery.

[Ca-dependent modulation of human glycine receptors expressed in cultured cell lines]

Glycine receptors (GlyRs) provide the main inhibitory neurotransmission in spinal cord and brainstem synapses of vertebrates. Fucile et al. (2000) discovered that elevation of intracellular Ca2+ caused rapid potentiation of GlyRs. This modulation develops in less than 100 ms. It is characterized by an increase in GlyR apparent affinity for glycine. It has been suggested that the phenomenon of Ca-induced potentiation involves an unknown Ca2+-binding protein (CaBP). Using the yeast two-hybrid system, screening of human brain cDNA library against the cytoplasmic loop of human alpha 1 subunit (GlyRhl) allowed us to identify five new interactors. One of them belongs to a family of Ca-binding proteins. We analyzed effect of "short" forms of this protein (CaBP-S) on functional properties of GlyRhl expressed in HEK-293 and CHO cells. Using whole-cell recordings and rapid agonist application we constructed concentration dependencies of glycine-induced currents. This analysis revealed statistical differences in EC50s between control cells (expressing only GlyRhl) and those expressing CaBP-S. In HEK-293 cells recorded under conditions of low intracellular Ca concentration (BAPTA 20 mM in the recording pipette), EC50 for glycine in control cells and expressing GlyRhl + CaBP-S were, correspondently, 68+/-49 microM (n = 29) and 409 +/-421 microM (n = 60). In CHO cells EC50 were 54+/-43 microM (n = 25) and 123 +/-104 microM (n = 28). These differences were statistically not significant at recording with intracellular solution containing high Ca concentration (50 microM). In this case EC50 were correspondently 35+/-28 microM (n = 7) and 64 +/-38 microM (n = 7). These results suggest that CaBP-S causes decrease of GlyR sensitivity to agonist through interaction with cytoplasmic domain of GlyR.

Antiviral drug discovery strategy using combinatorial libraries of structurally constrained peptides

We have developed a new strategy for antiviral peptide discovery by using lyssaviruses (rabies virus and rabies-related viruses) as models. Based on the mimicry of natural bioactive peptides, two genetically encoded combinatorial peptide libraries composed of intrinsically constrained peptides (coactamers) were designed. Proteomic knowledge concerning the functional network of interactions in the lyssavirus transcription-replication complex highlights the phosphoprotein (P) as a prime target for inhibitors of viral replication. We present an integrated, sequential drug discovery process for selection of peptides with antiviral activity directed against the P. Our approach combines (i). an exhaustive two-hybrid selection of peptides binding two phylogenetically divergent lyssavirus P's, (ii). a functional analysis of protein interaction inhibition in a viral reverse genetic assay, coupled with a physical analysis of viral nucleoprotein-P complex by protein chip mass spectrometry, and (iii). an assay for inhibition of lyssavirus infection in mammalian cells. The validity of this strategy was demonstrated by the identification of four peptides exhibiting an efficient antiviral activity. Our work highlights the importance of P as a target in anti-rabies virus drug discovery. Furthermore, the screening strategy and the coactamer libraries presented in this report could be considered, respectively, a general target validation strategy and a potential source of biologically active peptides which could also help to design pharmacologically active peptide-mimicking molecules. The strategy described here is easily applicable to other pathogens.

Functional interaction map of lyssavirus phosphoprotein: identification of the minimal transcription domains

Lyssaviruses, the causative agents of rabies encephalitis, are distributed in seven genotypes. The phylogenetically distant rabies virus (PV strain, genotype 1) and Mokola virus (genotype 3) were used to develop a strategy to identify functional homologous interactive domains from two proteins (P and N) which participate in the viral ribonucleoprotein (RNP) transcription-replication complex. This strategy combined two-hybrid and green fluorescent protein-reverse two-hybrid assays in Saccharomyces cerevisiae to analyze protein-protein interactions and a reverse genetic assay in mammalian cells to study the transcriptional activity of the reconstituted RNP complex. Lyssavirus P proteins contain two N-binding domains (N-BDs), a strong one encompassing amino acid (aa) 176 to the C terminus and a weak one in the 189 N-terminal aa. The N-terminal portion of P (aa 52 to 189) also contains a homomultimerization site. Here we demonstrate that N-P interactions, although weaker, are maintained between proteins of the different genotypes. A minimal transcriptional module of the P protein was obtained by fusing the first 60 N-terminal aa containing the L protein binding site to the C-terminal strong N-BD. Random mutation of the strong N-BD on P protein identified three highly conserved K residues crucial for N-P interaction. Their mutagenesis in full-length P induced a transcriptionally defective RNP. The analysis of homologous interactive domains presented here and previously reported dissections of the P protein allowed us to propose a model of the functional interaction network of the lyssavirus P protein. This model underscores the central role of P at the interface between L protein and N-RNA template.

Hyperosmotic stress response and regulation of cell wall integrity in Saccharomyces cerevisiae share common functional aspects

The osmosensitive phenotype of the hog1 strain is suppressed at elevated temperature. Here, we show that the same holds true for the other commonly used HOG pathway mutant strains pbs2 and sho1ssk2ssk22, but not for ste11ssk2ssk22. Instead, the ste11ssk2ssk2 strain displayed a hyperosmosensitive phenotype at 37 degrees C. This phenotype is suppressed by overexpression of LRE1, HLR1 and WSC3, all genes known to influence cell wall composition. The suppression of the temperature-induced hyperosmosensitivity by these genes prompted us to investigate the role of STE11 and other HOG pathway components in cellular integrity and, indeed, we were able show that HOG pathway mutants display sensitivity to cell wall-degrading enzymes. LRE1 and HLR1 were also shown to suppress the cell wall phenotypes associated with the HOG pathway mutants. In addition, the isolated multicopy suppressor genes suppress temperature-induced cell lysis phenotypes of PKC pathway mutants that could be an indication for shared targets of the PKC pathway and high-osmolarity response routes.

Home treatment of deep venous thrombosis with low molecular weight heparin: Long-term incidence of recurrent venous thromboembolism

Outpatient treatment of deep venous thrombosis (DVT) with low molecular weight heparin (LMWH) seems as safe and effective as inpatient treatment with unfractionated heparin (UFH). However, most of the randomized trials comparing a LMWH with UFH described clinical outcomes within 3-6 months. The long-term incidence of recurrent VTE after treatment of DVT with LMWH remains to be established. The primary objective of this retrospective study was to document the long-term incidence of recurrent venous thromboembolism (VTE) in patients with DVT treated with a LMWH, nadroparin in an outpatient basis. The patients were evaluated 46 months after inclusion in two cohorts comparing home treatment with nadroparin (n = 130) with in-hospital treatment with intravenous UFH (n = 149). More than 60% of the patients in the nadroparin group could be treated at home, either entirely or after a short stay in hospital. The age-adjusted thrombosis-free survival was not statistically significant between nadroparin and UFH-treated patients (P = 0.084). There was a nonsignificant trend favoring nadroparin as compared with UFH. The hazard ratio (HR) for recurrent VTE in the nadroparin group with respect to the UFH group was 0.44 (95% confidence interval, 0.17-1.12). No significant differences were observed in overall mortality or major hemorrhage between the two treatment groups. Our study suggests that home treatment of DVT with LMWH is at least as effective and safe as in-hospital UFH after a long-term follow-up period.

Recurrent venous thromboembolism in a Spanish population: incidence, risk factors, and management in a hospital setting

The major concern in the management of venous thromboembolism is the propagation of thrombus and rethrombosis. The incidence of recurrences and the duration of oral anticoagulant therapy in these patients are still controversial. The aim of this study was to determine the incidence, timing, and outcome of further thrombotic events after an initial episode of venous thromboembolism in a hospital setting. In addition, we evaluated potential risk factors for all these outcomes. This was designed as a retrospective analysis of all patients admitted to our Center with an episode of deep vein thrombosis and/or pulmonary embolism between 1986 and 1996. The patients included in the study had to be treated with unfractionated heparin or low molecular weight heparin, followed by at least 3 months of oral anticoagulants. Natural and acquired hemostasis inhibitors were assayed in patients aged less than 50 years. A total of 290 patients with a first episode of venous thromboembolism were included in the study. A total of 33 patients (11.9%, 95% confidence interval. 7.4-14.6) had recurrent episodes. The cumulative incidence of recurrent venous thromboembolism after 2, 5, and 10 years was 7.68, 10, and 12.4%, respectively. The incidence of rethrombosis was significantly higher in patients with idiopathic venous thromboembolism than in patients with secondary thrombosis. Abnormalities of hemostasis were found in 54.5% (95% confidence interval, 37.6-71.4) of the patients with recurrences and under the age of 50 years. Three of seven patients who stopped anticoagulant therapy after the second episode presented a third thrombotic event. In our study population, those patients with idiopathic venous thromboembolism seem to have an increased risk of recurrence. The second thrombotic episode occurs more frequently during the following 2 years after cessation of anticoagulation therapy. Our findings strongly support the use of long-term anticoagulant therapy in patients with recurrent venous thromboembolism.

Population pharmacokinetic approach to compare oral and i.v. administration of etoposide

The antitumor effect of etoposide (ETO) may be related to duration of exposure to a relatively low serum level while myelosuppression may be dependent on peak ETO serum levels. With regard to such therapeutic ranges, duration of exposure to predefined plasma ETO concentration ranges and the related AUC (expressed as percent of total AUC, pAUC) were used to compare pharmacokinetic profiles after oral and short time i.v. (1 h infusion) administration of identical ETO doses (100 mg/m2). Patients included in this study received i.v. (18 patients, short-term infusions) or oral (16 patients) ETO on different treatment schedules. Plasma ETO concentrations were determined by HPLC and population pharmacokinetic parameters were calculated (P-Pharm 1.4). Despite an 'apparent bioavailability' of 59%, oral administration of ETO was associated with the same time of exposure to a predefined 'therapeutic range' of 0.5-3 mg/l and a significantly higher pAUC compared to i.v. administration. By contrast, time of exposure to the probably more myelotoxic concentration range above 3 mg/l was significantly shorter and the related pAUC was highly significantly lower after oral than after i.v. administration. These findings demonstrate that oral ETO therapy is at least equivalent to short time i.v. therapy in terms of achieving specific target concentration ranges and avoiding peak concentrations.

Monitoring oral anticoagulant treatment from plasma stored for up to 48 hours and frozen plasma

BACKGROUND AND OBJECTIVE

The number of patients being referred for lifelong anticoagulant treatment has increased markedly in the last years. The prothrombin time test is sometimes difficult to perform the same day as sample collection. The aim of this study is to determine International Normalized Ratio (INR) and vitamin-K dependent factor levels of frozen plasma and plasma stored for up 48 hours.

DESIGN AND METHODS

The INR of 84 patients receiving acenocoumarol were determined fresh (0 hours), on samples stored between 2 degrees C and 8 degrees C for 24 hours and 48 hours, and on frozen samples (-40 degrees C) using 4 different thromboplastin reagents (Thromboplastin IS; Thromborel; Simplastin; and Thromboplastin D+G). In addition, factors II, VII, IX, X were determined in 34 of these patients in all these situations. We used the interclass correlation coefficient to compare the results obtained at 0 hours and the results obtained in the subsequent measurements. Both measurement and proportional errors were also estimated by linear regression analysis.

RESULTS

The correlation coefficient of the INR between fresh and frozen plasma was 0.98, 0.98, 0.92 and 0.97 for IS, Thromborel, Simplastin and D+G respectively. The correlation between 0 and 24 hours was 0. 98, 0.91, 0.95 and 0.85 for IS, Thromborel, Simplastin and D+G respectively. By 48 hours although IS still had r=0.94, Thromborel, Simplastin, and D+G had r=0.55, r=0.50 and r=0.81, respectively. By 24 hours in stored plasma and in frozen plasma the activity of vitamin-K dependent factors was slightly reduced (r=0.97 at 24h/r=0. 94 with frozen plasma for factor II, r=0.92/0.96 for factor VII, r=0. 83/0.98 for factor IX, and r=0.98/0.95 for factor X). By 48 hours however, significant reductions were noted in the activity of these factors (r=0.94 for factor II, r=0.88 for factor VII, r=0.70 for factor IX, and r=0.98 for factor X).

INTERPRETATION AND CONCLUSIONS

The INR can be reliable determined in frozen plasma and in plasma stored at 2-8 degrees C for up to 24 hours.

Elective splenectomy in relapsing thrombotic thrombocytopenic purpura

Between 20 and 40% of surviving patients with thrombotic thrombocytopenic purpura (TTP) have relapses. Plasma exchange therapy is usually effective in treating relapses, but this treatment does not prevent TTP recurrence. The role of splenectomy in relapsing TTP is still controversial. We describe a patient with multiple relapses of TTP who was successfully treated with elective splenectomy.

Home treatment of deep vein thrombosis: a two-years experience of a single institution

BACKGROUND AND OBJECTIVE

Low molecular weight heparin (LMWH) is known to be safe and effective for the initial treatment of patients with acute deep-vein thrombosis (DVT). Moreover, LMWH allows patients to be treated at home. However, only limited data are available on the feasibility of LMWH treatment at home in daily clinical practice.

DESIGN AND METHODS

We evaluated the feasibility, efficacy and safety of home treatment of DVT in a consecutive series of outpatients using LMWH over a two year period. The two main reasons for exclusion were concomitant pulmonary embolism and a high hemorrhagic risk. Patients were treated with 95 IU/kg bid of nadroparin for a minimum of 7 days. The study design allowed patients to go home immediately after diagnosis or to be discharged after a short hospital stay. Anticoagulation with acenocoumarol was started 2 days before discontinuing nadroparin.

RESULTS

From 1995 to 1997, 71 consecutive outpatients with DVT were treated with nadroparin. Ambulatory treatment was feasible in 39 patients (24 patients did not require admission and 15 patients were discharged in less than 48 hours). The remaining 32 patients were treated in hospital. The main causes for admission were the presence of serious comorbid conditions, the severity of symptoms in the involved leg and the inability to obtain a diagnosis. None of the patients had clinical recurrent venous thromboembolism during the initial treatment with nadroparin. One patient receiving nadroparin at home had a non-fatal major bleeding. None of the patients to whom the possibility of home therapy was offered wished to remain at hospital. However, only 26% of the home-treated patients injected the drug by themselves.

INTERPRETATION AND CONCLUSIONS

Home therapy of DVT with LMWH bid at doses adjusted to patient's body weight is feasible, efficient and safe. Over 50% of outpatients with DVT can be treated at home, either entirely or after a short stay in hospital. Nevertheless, before using this therapeutic alternative as a standard of practice, an adequate assessment of embolic and hemorrhagic risks, and comorbid conditions, should be made.

[Cutaneous B-cell lymphoma with aggressive clinical presentation: apropos of a case]

A patient with an atypical clinical presentation of cutaneous B-cell lymphoma is reported. He showed a rapidly growing tumour with areas of skin necrosis, haemorrhage, ulceration and suppuration in his upper back. There were involvement of contiguous anatomic site and extracutaneous spread. The histology showed diffuse lymphoid infiltration of the dermis. The cell morphology was that of a monotonous population of centroblasts. Treatment with CHOP and radiotherapy provided long-term complete remission. This case illustrates that primary cutaneous B-cell lymphoma may behave as a high-grade malignancy. Vigorous treatment with chemotherapy and radiotherapy is recommended in such cases.

[Skin lesions in epidemic Kaposi's sarcoma (AIDS): local control assessment and esthetic results of a schedule of superficial radiotherapy]

This prospective study was undertaken to evaluate the clinical response of 51 cutaneous lesions of epidemic Kaposi sarcoma in patients with AIDS (EKS/AIDS), obtained with the use of a scheme of superficial radiotherapy (3 Gy/fraction, three fractions weekly up to a total dose of 30 Gy). The mean follow-up time was 9.3 months and the mean time to progression of EKS/AIDS disease was 7-8 months. The initial clinical parameters (pain, size, edema, and esthetics) of each cutaneous lesion were compared with those obtained after one week, one month and three months of therapy. An objective pain improvement was observed in 72% of early lesions and with statistic significance (after one week p = 0.003). After one month of therapy a decrease in lesion size, edema, and esthetic improvement was observed in 78%, 71% and 77%, respectively. Although the evolution and prognosis of EKS/AIDS remains unchanged, it indeed provided palliation, with improvement of local control and esthetics, which together with the simplicity of its application and absence of untoward effects render this radiotherapy technique a very useful indication.

[Pharmacokinetics of etoposide short-term infusions within the scope of the GPOH therapy protocol]

Important interpatient variability of etoposide pharmacokinetics during continuous infusion has been reported and drug level targeting, therefore, been suggested. The current German therapeutic protocols are mainly based on short-term infusion. We determined pharmacokinetic parameters during short-term infusion in 18 children aged between 10/12 and 17 years on different therapeutic schedules in order to investigate interpatient variability. The dosages ranged from 66 to 200 mg/m2. In the subgroup of patients who received 150 mg/m2 (n = 10) the AUC was 106 +/- 15 micrograms.h/ml (range 82-139), clearance 24 +/- 3 ml/min/m2 (18-31), t1/2 3.5 +/- 0.4. To compare kinetic data of all 21 courses in 18 children, standard AUC was calculated (AUC/100 mg/m2). The AUC then was (68 +/- 17 micrograms.h/ml)/(100 mg/m2). Half-life was 3.3 +/- 0.7 h and total clearance 26 +/- 6 ml/min/m2, respectively. In 5 courses in children < 2 years (< 10 kg), pharmacokinetic parameters were within the normal range. In this group dosage was calculated per kg. Dose reduction of 31% (mean) resulted in 22% (mean) lower AUC's. In conclusion, interpatient variability of etoposide pharmacokinetics during short-term infusion is limited. Dose reduction in children < 2 years is not substantiated by our pharmacokinetic data.

Investigation of the variability of etoposide pharmacokinetics in children

PROBLEM

The interindividual variation of etoposide pharmacokinetics under different therapeutic schedules and the rationale of dose reduction in young children and newborns were investigated in the present study.

PATIENTS AND METHODS

We evaluated pharmacokinetic parameters during short-term infusion in 21 therapy cycles (18 children) on different therapeutic schedules (66-200 mg/m2). In 33 patients state levels (Css) during continuous infusion of 125 mg/m2/96 h were analyzed by an HPLC-method.

RESULTS

During short-term infusion half-life (3.3 +/- 0.7 h) and total body clearance (26 +/- 6 ml/min/m2) showed a relatively narrow range. Calculation of the area under the curve was standardized to a dosage of 100 mg/m2 (AUC/[100 mg/m2]). The AUC then was 68 +/- 17 (micrograms.h/ml)/(100 mg/m2) with a coefficient of variation of 25%. In the subgroup of 10 patients who received 150 mg/m2 the AUC was 106 +/- 15 micrograms.h/ml with only 14% coefficient of variation. In children < 2 years, pharmacokinetic parameters were within the normal range. Calculation of the doses the short-term infusion per kg resulted in a dose reduction or 31% (mean, n = 5) and in 22% (mean) lower AUC's. With continuous infusion of 125 mg/m2 etoposide the interpatient variability was greater with a 33% coefficient of variation of the Css (4.4 +/- 1.4 micrograms/ml; n = 24). Calculation of the doses per kg (age < 1 year) or 2/3.kg resulted in reduced Css. Standardization of these levels showed Css (125 mg/m2) of 4.6 +/- 1.4 micrograms/ml and a coefficient of variation of 31%.

CONCLUSIONS

Interpatient variability of etoposide pharmacokinetics at least during short-term infusion is limited. Dose reduction is not substantiated in children < 2 years by our pharmacokinetic data.