Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus

OBJECTIVE

Cannabis consumption during adolescence has been reported as a risk factor for psychotic-like experiences (PLEs) and schizophrenia. However, brain developmental processes associated with cannabis-related PLEs are still poorly described.

METHOD

A total of 706 adolescents from the general population who were recruited by the IMAGEN consortium had structural magnetic resonance imaging scans at both 14 and 19 years of age. We used deformation-based morphometry to map voxelwise brain changes between the two time points, using the pairwise algorithm in SPM12b. We used an a priori region-of-interest approach focusing on the hippocampus/parahippocampus to perform voxelwise linear regressions. Lifetime cannabis consumption was assessed using the European School Survey Project on Alcohol and other Drugs (ESPAD), and PLEs were assessed with the Comprehensive Assessment Psychotic-like experiences (CAPE) tool. We first tested whether hippocampus/parahippocampus development was associated with PLEs. Then we formulated and tested an a priori simple mediation model in which uncus development mediates the association between lifetime cannabis consumption and PLEs.

RESULTS

We found that PLEs were associated with reduced expansion within a specific region of the right hippocampus/parahippocampus formation, the uncus (p = .002 at the cluster level, p = .018 at the peak level). The partial simple mediation model revealed a significant total effect from lifetime cannabis consumption to PLEs (b = 0.069, 95% CI = 0.04-0.1, p =2 × 10^-16), as well as a small yet significant, indirect effect of right uncus development (0.004; 95% CI = 0.0004-0.01, p = .026).

CONCLUSION

We show here that the uncus development is involved in the cerebral basis of PLEs in a population-based sample of healthy adolescents.

Neural Correlates of Failed Inhibitory Control as an Early Marker of Disordered Eating in Adolescents

BACKGROUND

Binge eating and other forms of disordered eating behavior (DEB) are associated with failed inhibitory control. This study investigated the neural correlates of failed inhibitory control as a potential biomarker for DEB.

METHODS

The study used prospective longitudinal data from the European IMAGEN study adolescent cohort. Participants completed baseline assessments (questionnaires and a brain scan [functional magnetic resonance imaging]) at 14 years of age and a follow-up assessment (questionnaires) at 16 years of age. Self-reported binge eating and/or purging were used to indicate presence of DEB. Neural correlates of failed inhibition were assessed using the stop signal task. Participants were categorized as healthy control subjects (reported no DEB at both time points), maintainers (reported DEB at both time points), recoverers (reported DEB at baseline only), and developers (reported DEB at follow-up only). Forty-three individuals per group with complete scanning data were matched on gender, age, puberty, and intelligence (N = 172).

RESULTS

At baseline, despite similar task performance, incorrectly responding to stop signals (failed inhibitory control) was associated with greater recruitment of the medial prefrontal cortex and anterior cingulate cortex in the developers compared with healthy control subjects and recoverers.

CONCLUSIONS

Greater recruitment of the medial prefrontal and anterior cingulate regions during failed inhibition accords with abnormal evaluation of errors contributing to DEB development. As this precedes symptom onset and is evident despite normal task performance, neural responses during failed inhibition may be a useful biomarker of vulnerability for DEB. This study highlights the potential value of prospective neuroimaging studies for identifying markers of illness before the emergence of behavior changes.

From mother to child: orbitofrontal cortex gyrification and changes of drinking behaviour during adolescence

Adolescence is a common time for initiation of alcohol use and alcohol use disorders. Importantly, the neuro-anatomical foundation for later alcohol-related problems may already manifest pre-natally, particularly due to smoking and alcohol consumption during pregnancy. In this context, cortical gyrification is an interesting marker of neuronal development but has not been investigated as a risk factor for adolescent alcohol use. On magnetic resonance imaging scans of 595 14-year-old adolescents from the IMAGEN sample, we computed whole-brain mean curvature indices to predict change in alcohol-related problems over the following 2 years. Change of alcohol use-related problems was significantly predicted from mean curvature in left orbitofrontal cortex (OFC). Less gyrification of OFC was associated with an increase in alcohol use-related problems over the next 2 years. Moreover, lower gyrification in left OFC was related to pre-natal alcohol exposure, whereas maternal smoking during pregnancy had no effect. Current alcohol use-related problems of the biological mother had no effect on offsprings' OFC gyrification or drinking behaviour. The data support the idea that alcohol consumption during pregnancy mediates the development of neuro-anatomical phenotypes, which in turn constitute a risk factor for increasing problems due to alcohol consumption in a vulnerable stage of life. Maternal smoking during pregnancy or current maternal alcohol/nicotine consumption had no significant effect. The OFC mediates behaviours known to be disturbed in addiction, namely impulse control and reward processing. The results stress the importance of pre-natal alcohol exposure for later increases in alcohol use-related problems, mediated by structural brain characteristics.

Resilience and corpus callosum microstructure in adolescence

BACKGROUND

Resilience is the capacity of individuals to resist mental disorders despite exposure to stress. Little is known about its neural underpinnings. The putative variation of white-matter microstructure with resilience in adolescence, a critical period for brain maturation and onset of high-prevalence mental disorders, has not been assessed by diffusion tensor imaging (DTI). Lower fractional anisotropy (FA) though, has been reported in the corpus callosum (CC), the brain's largest white-matter structure, in psychiatric and stress-related conditions. We hypothesized that higher FA in the CC would characterize stress-resilient adolescents.

METHOD

Three groups of adolescents recruited from the community were compared: resilient with low risk of mental disorder despite high exposure to lifetime stress (n = 55), at-risk of mental disorder exposed to the same level of stress (n = 68), and controls (n = 123). Personality was assessed by the NEO-Five Factor Inventory (NEO-FFI). Voxelwise statistics of DTI values in CC were obtained using tract-based spatial statistics. Regional projections were identified by probabilistic tractography.

RESULTS

Higher FA values were detected in the anterior CC of resilient compared to both non-resilient and control adolescents. FA values varied according to resilience capacity. Seed regional changes in anterior CC projected onto anterior cingulate and frontal cortex. Neuroticism and three other NEO-FFI factor scores differentiated non-resilient participants from the other two groups.

CONCLUSION

High FA was detected in resilient adolescents in an anterior CC region projecting to frontal areas subserving cognitive resources. Psychiatric risk was associated with personality characteristics. Resilience in adolescence may be related to white-matter microstructure.

Orthognathic surgery for the complete rehabilitation of Moebius patients: principles, timing and our experience

Moebius syndrome is a rare disorder found in approximately 1/100,000 neonates and the treatment of facial palsy is now well established worldwide and consists of free-muscle transplants reinnervated with motor nerves. Dentofacial deformities are often detected in Moebius patients, and different degrees of micrognathia are often present, particularly in patients with complete expressions of Moebius syndrome. However only two published reports have described the surgical treatment of such anomalies in these patients; in both cases, the suggested approach consisted of orthognathic surgery followed by soft-tissue management. In this paper we discuss the indications and correct timing of orthognathic surgery and suggest to perform facial animation at an early age and then to wait for the completion of maxillofacial skeletal growth before performing orthognathic surgery. Finally, facial animation should precede orthognathic surgery in adult patients to prevent lower lip deformities and to ensure more predictable and satisfactory results.

PyXNAT: XNAT in Python

As neuroimaging databases grow in size and complexity, the time researchers spend investigating and managing the data increases to the expense of data analysis. As a result, investigators rely more and more heavily on scripting using high-level languages to automate data management and processing tasks. For this, a structured and programmatic access to the data store is necessary. Web services are a first step toward this goal. They however lack in functionality and ease of use because they provide only low-level interfaces to databases. We introduce here PyXNAT, a Python module that interacts with The Extensible Neuroimaging Archive Toolkit (XNAT) through native Python calls across multiple operating systems. The choice of Python enables PyXNAT to expose the XNAT Web Services and unify their features with a higher level and more expressive language. PyXNAT provides XNAT users direct access to all the scientific packages in Python. Finally PyXNAT aims to be efficient and easy to use, both as a back-end library to build XNAT clients and as an alternative front-end from the command line.

Common structural correlates of trait impulsiveness and perceptual reasoning in adolescence

BACKGROUND

Trait impulsiveness is a potential factor that predicts both substance use and certain psychiatric disorders. This study investigates whether there are common structural cerebral correlates of trait impulsiveness and cognitive functioning in a large sample of healthy adolescents from the IMAGEN project.

METHODS

Clusters of gray matter (GM) volume associated with trait impulsiveness, Cloningers' revised temperament, and character inventory impulsiveness (TCI-R-I) were identified in a whole brain analysis using optimized voxel-based morphometry in 115 healthy 14-year-olds. The clusters were tested for correlations with performance on the nonverbal tests (Block Design, BD; Matrix Reasoning, MT) of the Wechsler Scale of Intelligence for Children IV reflecting perceptual reasoning.

RESULTS

Cloningers' impulsiveness (TCI-R-I) score was significantly inversely associated with GM volume in left orbitofrontal cortex (OFC). Frontal clusters found were positively correlated with performance in perceptual reasoning tasks (Bonferroni corrected). No significant correlations between TCI-R-I and perceptual reasoning were observed.

CONCLUSIONS

The neural correlate of trait impulsiveness in the OFC matches an area where brain function has previously been related to inhibitory control. Additionally, orbitofrontal GM volume was associated with scores for perceptual reasoning. The data show for the first time structural correlates of both cognitive functioning and impulsiveness in healthy adolescent subjects.

Boys do it the right way: sex-dependent amygdala lateralization during face processing in adolescents

Previous studies have observed a sex-dependent lateralization of amygdala activation related to emotional memory. Specifically, it was shown that the activity of the right amygdala correlates significantly stronger with memory for images judged as arousing in men than in women, and that there is a significantly stronger relationship in women than in men between activity of the left amygdala and memory for arousing images. Using a large sample of 235 male adolescents and 235 females matched for age and handedness, we investigated the sex-specific lateralization of amygdala activation during an emotional face perception fMRI task. Performing a formal sex by hemisphere analysis, we observed in males a significantly stronger right amygdala activation as compared to females. Our results indicate that adolescents display a sex-dependent lateralization of amygdala activation that is also present in basic processes of emotional perception. This finding suggests a sex-dependent development of human emotion processing and may further implicate possible etiological pathways for mental disorders most frequent in adolescent males (i.e., conduct disorder).

The IMAGEN study: reinforcement-related behaviour in normal brain function and psychopathology

A fundamental function of the brain is to evaluate the emotional and motivational significance of stimuli and to adapt behaviour accordingly. The IMAGEN study is the first multicentre genetic-neuroimaging study aimed at identifying the genetic and neurobiological basis of individual variability in impulsivity, reinforcer sensitivity and emotional reactivity, and determining their predictive value for the development of frequent psychiatric disorders. Comprehensive behavioural and neuropsychological characterization, functional and structural neuroimaging and genome-wide association analyses of 2000 14-year-old adolescents are combined with functional genetics in animal and human models. Results will be validated in 1000 adolescents from the Canadian Saguenay Youth Study. The sample will be followed up longitudinally at the age of 16 years to investigate the predictive value of genetics and intermediate phenotypes for the development of frequent psychiatric disorders. This review describes the strategies the IMAGEN consortium used to meet the challenges posed by large-scale multicentre imaging-genomics investigations. We provide detailed methods and Standard Operating Procedures that we hope will be helpful for the design of future studies. These include standardization of the clinical, psychometric and neuroimaging-acquisition protocols, development of a central database for efficient analyses of large multimodal data sets and new analytic approaches to large-scale genetic neuroimaging analyses.

Pharmacokinetics and pharmacodynamics of sequential intravenous and subcutaneous teicoplanin in critically ill patients without vasopressors

OBJECTIVE

To compare the pharmacokinetic parameters of sequential intravenous and subcutaneous teicoplanin in the plasma of surgical intensive care unit patients.

DESIGN AND SETTING

Prospective, randomized, crossover study in the surgical ICU of a university hospital.

PATIENTS

Twelve patients with a suspected nosocomial infection, a serum albumin level higher than 10 g/l, body mass index less than 28 kg/m(2), and estimated creatinine clearance higher than 70 ml/min.

INTERVENTIONS

Teicoplanin was first administered intravenously as a loading dose of 6 mg/kg per 12 h for 48 h and then continued at a daily dose of 6 mg/kg. On the fourth day patients were randomized in two groups according to the order of the pharmacokinetic studies.

MEASUREMENTS AND RESULTS

Serial plasma samples were obtained to measure teicoplanin levels. Compared with a 30-min intravenous infusion the peak concentration of teicoplanin after a 30-min subcutaneous administration occurred later (median 7 h, range 5-18) and was lower (16 micro g/ml, 9-31; vs. 73, 53-106). Despite large and unpredictable interindividual differences no significant differences between subcutaneous and intravenous administration were observed in: trough antibiotic concentrations (10 micro g/ml, 6-24; vs. 9, 5-30), the area under the teicoplanin plasma concentration vs. time curves from 0 to 24 h (AUC(0-24h); 309 micro g/ml per minute, 180-640; vs. 369, 171-955), the proportion of the dosing interval during which the plasma teicoplanin concentration exceeded 10 micro g/ml (96%, 0-100%; vs. 79%, 13-100%), and the ratio of AUC(0-24h) to 10 (77, 45-160; vs. 92, 43-239).

CONCLUSIONS

In critically ill patients without vasopressors a switch to the subcutaneous teicoplanin after an initial intravenous therapy seems to give comparable pharmacodynamic indexes of therapeutic success.

Speech recognition in elderly cochlear implant recipients

The benefits of cochlear implantation in the adult and paediatric populations are well established. Cochlear implantation in the geriatric population still remains controversial because of the misconception that elderly patients might perform poorly. The purpose of this study was to report the speech performance of 16 patients over 65 years of age implanted with a Nucleus multichannel cochlear implant and to compare it with that of a control group of 14 adults aged between 41 and 59 years. At the 12 months postoperative evaluation, no significant differences were detected on speech performances between the elderly patients and the control group. The mean word recognition scores were 72.5% for the elderly group and 82% for the control group. The mean everyday sentence recognition scores were 72.5% for the elderly group and 85.7% for the control group. Overall, the results are encouraging and demonstrate that the elderly population with profound hearing loss obtain significant benefits from cochlear implantation despite the age-related auditory processing problems.

[Multi-channel cochlear implant in cochlear ossification]

Cochlear ossification, considered until only a few years ago as a contraindication for cochlear implants (C.I.), may now be managed by means of a wide variety of surgical techniques. In cases with massive ossification, the drill-out circummodiolar technique described by Gantz et al. in 1988 and successively modified by Balkany et al. in 1997 may be adopted. The technique of electrode insertion in the scala vestibuli, perfected by Steenerson et al. in 1990, may be used when cochlear ossification has spread no further than the scala tympani. Other methods call for a groove to be drilled along the proximal tip of the basal turn of the cochlea (Cohen and Waltzman, 1993), the insertion of electrodes through the middle cranial fossa (Colletti et al., 2000), or the utilization of a double electrode array (Bredberg et al., 1997, Lenarz et al., 2001). This study reports the experience conducted at the Cochlear Implants Centre of the Otorhinolaryngoiatrics, Otological and Otoneurological Microsurgery Section of the University of Parma in a group of 15 patients who underwent C.I. in the presence of varying degrees of ossification. In 3 cases the ossification was limited to the region of the round window and a few millimetres of the scala tympani; cochleostomy was performed anteriorly and inferiorly to the anterior niche of the round window. In 11 cases (of which 3 of pediatric age), the ossification had spread to the horizontal portion of the scala tympani; in these cases, the electrodes were inserted in the scala vestibuli. The scala vestibuli was opened by drilling anteriorly to the round window and superiorly to the spiral ligament. In the only case of massively ossified cochlea, it was possible to partially insert the electrodes in a circum-modiolar tunnel. In the 12-month follow-up hearing test, the 3 patients with ossification of the round window region and the first millimetres of the scala tympani respectively averaged 61.6% in recognizing 2-syllable words and 59% in recognizing words embedded in phrases. The averages on the 12-month follow-up hearing test in the 8 adult patients who received the implant in the scala vestibuli were 80.6% in recognizing 2-syllable words and 89.1% in recognizing words in phrases. The 3 pediatric patients were classified on the Geers and Moog scale, which situated 2 of them in the 6th category of perception and 1 of them in the 4th category of perception. As regards the only case of massive cochlear ossification, the patient underwent surgery recently, and the sole follow-up available is the one conducted after only 3 months; the vowel identification average was 55%; the average on the VCV test was 31%; and the 2-syllable word recognition average was 20%.

Stabilization of recombinant adenovirus: site-directed mutagenesis of key asparagine residues in the hexon protein

The quality and stability of recombinant adenovirus preparations for gene therapy trials are currently analyzed by anion-exchange HPLC. It was shown that the retention time of the adenovirus peak increased over the course of time upon storage in current liquid formulations. The number of isoaspartate residues at the outer surface of the particles also increased in parallel in these preparations. A recombinant adenovirus AV3760 was constructed with a modified hexon protein in which all four accessible Asn residues engaged in Asn-Gly pairs were changed into Leu (Asn244, Asn255, Asn437) or Ala (Asn276). The retention time of AV3760, as measured by HPLC, was unchanged after 2 months at +20 degrees C as opposed to the control adenovirus. This demonstrates that the shift in retention time is caused by an increase in carboxyl groups on the outer surface of the virion due to deamidation of the above Asn residues. The modifications introduced in the hexon protein reduced the rate of Asn deamidation, without adverse effects on the infectivity of the virions. By reducing microheterogeneity in recombinant adenovirus, this work represents a significant advance in the development of a stable pharmaceutical vector for gene therapy.

Polypeptide composition of an adenovirus type 5 used in cancer gene therapy

For cancer gene therapy, a recombinant adenovirus serotype 5 named RPR/INGN201 has been constructed by susbtitution of the E1 region with human tumor suppressor gene p53. The protein components of RPR/INGN201 virions were separated by reversed-phase HPLC and were individually identified by electrospray time-of-flight mass spectrometry and N-terminal sequencing, both on intact proteins and on their proteolytic fragments after trypsin digestion. Twenty-five peptide components of the proteome (including fiber) with greater than 0.25-0.5% contribution to the protein content of the virus were identified and characterized. Fiber was confirmed to be partially glycosylated (both the non-glycosylated and the monoglycosylated states were identified), and two proteins were isolated and identified as phosphorylation derivatives, namely protein V (non-phosphorylated and monophosphorylated) and protein IIIa (mono- and diphosphorylated). This new analytical tool proved to be very useful not only for refining our current knowledge of the polypeptide repertoire of purified infectious virions but also for monitoring and very rapidly identifying structural modifications resulting from changes in the manufacturing process. It was also used successfully for the characterization of various adenoviral constructs.

An improved anion-exchange HPLC method for the detection and purification of adenoviral particles

We have developed an anion-exchange high-performance liquid chromatography (HPLC) method using Q Sepharose XL (Amersham Pharmacia Biotech) as adsorbent to analyze samples containing adenovirus. This method has several major advantages over the HPLC method previously described for quantitating particles, namely (1) a >10-fold improvement in the detection limit of adenovirus in crude preparations; (2) absence of interferences originating from nucleic acids and proteins which usually contaminate crude samples; (3) unprecedented sharpness and symmetry of adenovirus peak, rendering the identification of the viral peak unambiguous, even in extremely crude and dilute preparations; and (4) no enzymatic treatment required even for crude samples. This assay was used to quantitate particles in samples taken at the transfection and amplification stages of production of various recombinant adenovirus, and in cultures of wild-type adenovirus of different serotypes. A modification of this analytical method was also developed for the purification of infectious adenovirus particles, including fiber-modified and third-generation recombinant viruses, giving highly purified preparations from low-titer crude lysates with an excellent overall recovery (50-74%).

Prognostic value of response after three MOPP cycles in Hodgkin's disease--stage III and IV

Sixty-eight patients with Hodgkin's disease stage III and IV were evaluated after three out of six MOPP cycles. At that time, 46 (68%) were classified as early responders and 22 as slow responders. The criteria of response were: disappearance of B symptoms, decrease in the size of the largest lymph nodes (by more than 50%) and significant reduction (more than 20%) of mediastinal enlargement. Out of 43 early responders, 38 were in complete remission after six MOPP cycles and only five out of 22 slow responders. Such an early response is only related to the absence of B symptoms at the time of diagnosis (p less than 0.05). The survival curves of early responders and slow responders were significantly different (p less than 0.02). A rapid erythrocyte sedimentation rate (ESR) (greater than 50 mm) was the most frequently abnormal sign found in the group not responding after three MOPP cycles (p less than 0.0001). Such a significant prognostic value of early response is observed for stage III but not for stage IV patients. We conclude that early clinical response after three MOPP cycles is a good prognostic factor which must be kept in mind in the formulation of the therapeutic regimen for Hodgkin's disease stage III and IV.